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Адсорбция и адгезия полимеров. Композитные пленки (иностранные источники 2010-2014 гг.)

Журнальные статьи

Awaja, Firas; Zhang, Shengnan; McKenzie, David R. Sticky nano-thin films for the adhesion of polymers //APPLIED SURFACE SCIENCE Volume: 285 Pages: 893-899 Part: B Published: NOV 15 2013

Nanometre thick size films (about 2 nm thick) that were plasma deposited using a mixture of polymerizing and non-polymerizing gases on a PEEK polymer surface resulted in a remarkable autohesive strength (up to 10 fold when compared with the untreated control). Experimental results on autohesion of semicrystalline PEEK surfaces treated with plasma immersion ion implantation and deposition (PIIID) showed exceptionally strong autohesive bonds in lap-shear testing. Electron spin resonance (ESR) showed that the radical concentration increased linearly with plasma bias voltage. X-ray photoelectron spectroscopy (XPS) measurements showed no correlation between autohesive bonding strength and the concentration of oxygen and nitrogen elements and or the concentration of C-O functional groups on the surface. Contact angle measurements showed that surface energy also showed no correlation. Bond strength values are linked with the percentage of the sp3 components of the C Is region fitting in XPS spectra. There was strong relationship between the plasma treatment bias voltage and the plasma generated free radical density in the deposited thin film. Bond strength values are also correlated with the percentage of the sp3 components of the C Is region fitting in XPS spectra. Free radicals induced covalent bonding might be suggested as the major contributor that leads to that the remarkable increase of the adhesion strength. (C) 2013 Elsevier B.V. All rights reserved.

Berkovich, Anna K.; Lukashev, Eugeny P.; Melik-Nubarov, Nickolay S. Dipole potential as a driving force for the membrane insertion of polyacrylic acid in slightly acidic milieu //BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES Volume: 1818 Issue: 3 Pages: 375-383 Published: MAR 2012

In this work, we report on the interaction of polyacrylic acid with phosphatidylcholine bilayers and monolayers in slightly acidic medium. We found that adsorption of polyacrylic acid on liposomes composed of egg lecithin at pH 4.2 results in the formation of small pores permeable for low molecular weight solutes. However, the pores were impermeable for trypsin indicating that no solubilization of liposomes occurred. The pores were permeable for both positively charged trypsin substrate N-benzoyl-L-arginine ethyl ester and negatively charged pH-indicator pyranine. Two lines of evidence were obtained confirming the involvement of the membrane dipole potential in the insertion of polyacrylic acid into lipid bilayer. (i) Addition of phloretin, a molecule which is known to decrease dipole potential of lipid bilayer, reduced the rate of a polyacrylic acid induced leakage of pyranine from liposomes. (ii) Direct measurements of air/lipid monolayer/water interface surface potential using Kelvin probe showed that adsorption of polyacrylic acid at pH 4.2 induced a decrease in both boundary and dipole potential by 37 and 62 mV for ester lipid dioleoylphosphatidylcholine (DOPC). Replacement of DOPC by ether lipid 1,2-di-O-oleyl-sn-glycero-3-phosphocholine (DiOOPC) which is known to form monolayers and bilayers with only minor dipole component of membrane potential showed that addition of PAA produced similar response in the boundary potential (by 50 mV) but negligible response in dipole potential of monolayer. These observations agree with our assumption that dipole potential is an important driving force for the insertion of polyacids into biological membranes. (C) 2011 Elsevier B.V. All rights reserved.

Brzozowska, A. M.; Spruijt, E.; de Keizer, A.; et al. On the stability of the polymer brushes formed by adsorption of Ionomer Complexes on hydrophilic and hydrophobic surfaces //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 353 Issue: 2 Pages: 380-391 Published: JAN 15 2011

We have studied the effect of normal forces and shear forces on the stability and functionality of a polymer brush layer formed upon adsorption of polymeric micelles on hydrophilic and hydrophobic surfaces. The micelles consist of oppositely charged polyelectrolyte blocks (poly(acrylic acid) and poly(N-methyl 2-vinyl pyridinium iodide), and a neutral block (poly(vinyl alcohol)) or neutral grafts (poly(ethylene oxide)). The strength of the attachment of the micellar layers to various substrates was evaluated with Atomic Force Microscopy. Flow cell experiments allowed for the evaluation of long-term stability of coatings in lateral flow. Fixed angle optical reflectometry was used to quantify protein (BSA) adsorption on the micellar layers after their exposure to flow. The results show that adsorbed micellar layers are relatively weakly attached to hydrophobic surfaces and much stronger to hydrophilic surfaces, which has a significant impact on their stability. Adsorbed layers maintain their ability to suppress protein adsorption on hydrophilic surfaces but not on hydrophobic surfaces. Due to the relatively weak attachment to hydrophobic surfaces the structure of adsorbed layers may easily be disrupted by lateral forces, such that the complex coacervate-brush structure no longer exists. (C) 2010 Elsevier Inc. All rights reserved.

Fukushima, Tomohiro; Horike, Satoshi; Inubushi, Yasutaka; et al. Solid Solutions of Soft Porous Coordination Polymers: Fine-Tuning of Gas Adsorption Properties

Joshy, K. S.; Paul, Willi; Sharma, Chandra P. Copper complexed polymer carriers for IgG adsorption //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 352 Issue: 1 Pages: 178-185 Published: DEC 1 2010

Cost effective adsorption matrix is recently, a much sought after alternative to the normal and expensive forms of matrices that are being used for the separation and purification of therapeutic molecules like immunoglobulins. A study therefore, has been focussed on developing copper complexed poly (vinyl alcohol) [PVA] and poly (styrene allyl alcohol) [PSA] gel beads for the separation of immunoglobulin G (IgG) from aqueous solutions. The copper-immobilized PVA and PSA gel beads were prepared, characterized and the copper content was estimated using EDX analysis. Further compatibility tests such as erythrocyte aggregation, lyses and cell counting were also investigated. An increase in the IgG adsorption capacities was achieved with the copper immobilized micro particles, when compared with the unmodified particles. (C) 2010 Elsevier Inc. All rights reserved.

Kalidhasan, S.; KrishnaKumar, A. Santhana; Rajesh, Vidya; et al. Ultrasound-assisted preparation and characterization of crystalline cellulose-ionic liquid blend polymeric material: A prelude to the study of its application toward the effective adsorption of chromium //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 367 Pages: 398-408 Published: FEB 1 2012

The molecular interaction of biopolymers with an array of substrates offers interesting insight into the adsorption phenomenon. The present work proposes the preparation and characterization of cellulose-methyltrioctylammonium chloride (MeTOACl)-a room temperature ionic liquid (IL) blend polymeric sorbent and its application for the adsorption of carcinogenic chromium(VI). The blend adsorbent material was synthesized in a relatively green solvent (methylisobutylketone) medium by ultrasonication. The mechanism of interaction of biopolymer with the ionic liquid could be conceptualized as electrostatic attraction, hydrogen bonding, and Van der Waals force of attraction with the hydroxyl groups of cellulose as a bilayer assembly. The composition, crystallinity, and the surface area of the prepared material were comprehensively characterized using FT-IR, solid-state C-13 NMR, TGA, XRD, SEM, EDX, XPS, and BET isotherm study. The adsorption capacity of chromium(VI) calculated from Langmuir isotherm model was found to be 38.94 mg g(-1), with adherence to the second-order kinetics. The study of thermodynamic parameters that affect the sorption process indicated the spontaneity and exothermic nature of adsorption. The green aspect in the methodology is brought out in the regeneration of the adsorbent, where Cr(VI) could be effectively reduced to the less toxic Cr(III) using ascorbic acid. (C) 2011 Elsevier Inc. All rights reserved.

Kyzas, George Z.; Lazaridis, Nikolaos K.; Bikiaris, Dimitrios N. Optimization of chitosan and beta-cyclodextrin molecularly imprinted polymer synthesis for dye adsorption // CARBOHYDRATE POLYMERS Volume: 91 Issue: 1 Pages: 198-208 Published: JAN 2 2013

In this study, two types of novel molecularly imprinted polymers (MIPs) were prepared, for toxic and carcinogenic dyes adsorption. Substrates of the polymeric matrix of the two MIPs were beta-cyclodextrin and chitosan. The conditions in the polymerization/imprinting stage and in the rebinding/adsorption step were optimized. The effect of a range of parameters (polymer, cross-linker, and initiator concentrations, reaction time and pH) on the selectivity and adsorption capacity of the dye-MIPs were investigated. Their dye rebinding properties were demonstrated by equilibrium batch experiments (fitting with Freundlich model) and their kinetic rates were exported by the pseudo-first order model. Additionally, a thermodynamic evaluation was carried out through the determination of enthalpy, entropy, and free energy. The selectivity of MIPs was elucidated by their different rebinding capabilities in a trichromatic mixture (composed of related structurally dyes). Regeneration/reuse of the dye-loaded polymers was evaluated via sequential adsorption-desorption cycles. (C) 2012 Elsevier Ltd. All rights reserved.

Lee, Yihui; Chen, Sihzih; Tu, Hsinling; et al. In Situ STM Revelation of the Adsorption and Polymerization of Aniline on Au(111) Electrode in Perchloric Acid and Benzenesulfonic Acid // LANGMUIR Volume: 26 Issue: 8 Pages: 5576-5582 Published: APR 20 2010

In situ scanning tunneling microscopy (STM) was used to study the adsorption and polymerization of aniline on Au(111) single-crystal electrode in 0.1 M perchloric acid and 0.1 M benzenesulfonic acids (BSA) containing 30 mM aniline, respectively. At the onset potential of aniline's oxidation. similar to 0.8 V [vs reversible hydrogen electrode], aniline molecules were adsorbed in highly ordered arrays, designated as (3 x 2 root 3) and (4 x 2 root 3) in perchloric acid and BSA, respectively. These structures consisted of intermingled aniline molecules and perchlorate or BSA(-) anions zigzagging in the < 110 > directions in HClO(4) and in the < 121 > directions in BSA. The coverage of aniline admolecule on Au(111) was lower in BSA than in HClO(4). Raising the potential to 0.9 V or more positive values triggered the oxidation and polymerization of aniline. With aniline molecules;arranging in a way similar to the backbone of PAN in HClO(4), they readily coupled with each other to produce linear polymeric chains aligned predominantly in the < 110 > directions of the Au(111). Compared with the results observed in H(2)SO(4) (Lee et al. et al. J. Am. Chem. Soc. 2009, 131, 6468), the rate of polymerization was slower in HClO(4) and the produced PAN molecules tended to aggregate on the Au(111) electrode. PAN molecules generated in HClO(4) were anomalously shorter than those formed in H(2)SO(4). In 0.1 M BSA, PAN molecules produced by small overpotential (eta < 100 mV) could assume linear chains or 3D aggregates, depending on [aniline]. These results revealed molecular level details in electropolymerization of aniline, highlighting the important role of anion in controlling the conformation of PAN molecules and the texture of PAN film. 33) Ghanem, Bader S.; Hashem, Mohammed; Harris, Kenneth D. M.; et al. Triptycene-Based Polymers of Intrinsic Microporosity: Organic Materials That Can Be Tailored for Gas Adsorption //MACROMOLECULES Volume: 43 Issue: 12 Pages: 5287-5294 Published: JUN 22 2010

Leitsmann, R.; Boehm, O.; Plaenitz, Ph.; et al. Adsorption mechanisms of fluorocarbon polymers at ultra low-k surfaces //SURFACE SCIENCE Volume: 604 Issue: 19-20 Pages: 1808-1812 Published: SEP 2010

We report ab initio investigations for the adsorption mechanisms of fluorocarbon polymers at ultra low-k (ULK) surfaces. As prototypical example we study a C2F4-molecule adsorbed at a passivated SiO2:CH3(001) surface. The calculated adsorption energies between 1.37 and 1.95 eV imply a chemisorption bonding mechanism. The detailed analysis of all investigated structures provides a simple rule to make a rough estimate of the stability of adsorbed fluorocarbon polymers. In addition, an adsorption pathway is proposed and used to suggest a possible adsorption mechanism, triggered by an electron transfer between the ULK surface and the C2F4 molecule. (C) 2010 Elsevier B.V. All rights reserved.

Li, Yunbo; Li, Haixia; Sun, Yantao; et al. A Study of Complex Formation Between Polyacrylic Acid and Poly(Ethylene Oxide) by Near Resonance Rayleigh Scattering //APPLIED SPECTROSCOPY Volume: 64 Issue: 6 Pages: 682-686 Published: JUN 2010

A series of near resonance Rayleigh scattering (NRRS) experiments has been performed on the phase behavior of complex formation between polyacrylic acid (PAA) and poly(ethylene oxide) (POE). On the basis of the theory of resonance scattering, as one new method compared to resonance Rayleigh scattering (RRS), NRRS was demonstrated to investigate polymer solutions. The results indicated that the complex formation induces an increase of the intensity of resonance scattering and the phase segregation leads to distortion of the resonance scattering spectrum with decreasing pH value. The collapse of macromolecular chains is attributed to the contraction of PAA chains and association between PAA and POE. Moreover, NRRS can show more information than RRS on the basis of their scattering spectra.

Lian, Fei; Xing, Baoshan; Zhu, Lingyan Comparative study on composition, structure, and adsorption behavior of activated carbons derived from different synthetic waste polymers //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 360 Issue: 2 Pages: 725-730 Published: AUG 15 2011

The composition, structure, and adsorption behavior of activated carbons (ACs) derived from three different types of waste polymers, i.e., tire rubber (TR), polyvinyl chloride (PVC), and polyethyleneterephtalate (PET), by KOH activation were compared. The AC derived from PET exhibited the largest surface area (2831 m(2)/g) and pore volume (1.68 cm(3)/g) due to the homogenous aromatic composition of PET. The AC derived from PVC exhibited relatively lower surface area (2666 m2/g) but more narrowed pore size distribution (2-3 nm). The complex composition and high ash content of tire particles resulted in AC product with significantly lower surface area (398.5 m(2)/g) and heterogeneous pore width. Adsorption data of methylene blue (MB) were fitted well by Langmuir equation, indicating monolayer coverage on the ACs. The high oxygen content of PET-derived AC heavily affected its adsorption to MB and iodine. Due to the remarkable surface area and highly mesoporous structures, ACs based on both PET and PVC exhibited much higher adsorption capacities than that of TR and commercial coal-based AC (F400). This study demonstrates that the properties of ACs are highly dependent on their starting polymers and the potential of converting synthetic polymer waste into effective adsorbents for environmental remediation and cleanup. (C) 2011 Elsevier Inc. All rights reserved.

Mikutta, Robert; Zang, Ulrich; Chorover, Jon; et al. Stabilization of extracellular polymeric substances (Bacillus subtilis) by adsorption to and coprecipitation with Al forms //GEOCHIMICA ET COSMOCHIMICA ACTA Volume: 75 Issue: 11 Pages: 3135-3154 Published: JUN 1 2011

Extracellular polymeric substances (EPS) are continuously produced by bacteria during their growth and metabolism. In soils, EPS are bound to cell surfaces, associated with biofilms, or released into solution where they can react with other solutes and soil particle surfaces. If such reaction results in a decrease in EPS bioaccessibility, it may contribute to stabilization of microbial-derived organic carbon (OC) in soil. Here we examined: (i) the chemical fractionation of EPS produced by a common Gram positive soil bacterial strain (Bacillus subtilis) during reaction with dissolved and colloidal Al species and (ii) the resulting stabilization against desorption and microbial decay by the respective coprecipitation (with dissolved Al) and adsorption (with Al(OH)(3(am))) processes. Coprecipitates and adsorption complexes obtained following EPS-Al reaction as a function of pH and ionic strength were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The stability of adsorbed and coprecipitated EPS against biodegradation was assessed by mineralization experiments for 1100 h. Up to 60% of the initial 100 mg/L EPS-C was adsorbed at the highest initial molar Al:C ratio (1.86), but this still resulted only in a moderate OC mass fraction in the solid phase (17 mg/g Al(OH)(3(am))). In contrast, while coprecipitation by Al was less efficient in removing EPS from solution (maximum values of 33% at molar Al: C ratios of 0.1-0.2), the OC mass fraction in the solid product was substantially larger than that in adsorption complexes. Organic P compounds were preferentially bound during both adsorption and coprecipitation. Data are consistent with strong ligand exchange of EPS phosphoryl groups during adsorption to Al(OH)(3(am)), whereas for coprecipitation weaker sorption mechanisms are also involved. X-ray photoelectron analyses indicate an intimate mixing of EPS with Al in the coprecipitates, which is not observed in the case of EPS adsorption complexes. The incubation experiments showed that both processes result in overall stabilization of EPS against microbial decay. Stabilization of adsorbed or coprecipitated EPS increased with increasing molar Al: C ratio and biodegradation was correlated with EPS desorption, implying that detachment of EPS from surface sites is a prerequisite for microbial utilization. Results indicate that the mechanisms transferring EPS into Al-organic associations may significantly affect the composition and stability of biomolecular C, N and P in soils. The observed efficient stabilization of EPS might explain the strong microbial character of organic matter in subsoils. (C) 2011 Elsevier Ltd. All rights reserved.

Ridgway, Cathy J.; Gane, Patrick A. C. Size-selective absorption and adsorption in anionic pigmented porous coating structures: case study cationic starch polymer versus nanofibrillated cellulose //CELLULOSE Volume: 20 Issue: 2 Pages: 933-951 Published: APR 2013

The use of nano- or microfibrillar cellulose (NFC or MFC) in papermaking is generally hampered by high cost and potentially wasteful use in typical wet end applications. The solubility and fines nature of the material makes it inefficient to retain, and when retained it is generally inefficiently applied within the spatial distribution of the paper fibre matrix. The benefits of capturing the important NFC in a layer structure, to enhance surface and stiffness properties of paper, board and laminates whereby NFC is entrapped at the surface of a fibrous web by forming an in situ composite, were previously shown for the exemplified case of modified porous calcium carbonate, as might be used in an inkjet coating application (Ridgway and Gane in Cellulose 19(2):547-560, 2011). The NFC is seen to integrate itself within the larger interparticle porous structure providing excellent holdout and thin layer continuity, essential in developing an efficient concentration of the NFC at the surface of the substrate. The effect is likened to the well-known I-beam construction. The concept need not be confined to porous pigments, as any pigment coating structure that absorbs and holds the NFC, thus creating an in situ composite, could be used. The aim of this study is to look at a range of different pigments and investigate how these could be used as coating structures by measuring the effect on the pore structure before and after absorbing NFC. This is achieved by using model porous tablet blocks made from the respective anionic coating formulations. The penetration of cationic starch solution, as might be applied for surface sizing on paper, is studied for comparison. The use of cationic starch is considered in the industry to provide reasonably effective surface concentrations due to the electrostatically driven adsorption to the anionic pore surfaces. The effect of water alone on the coating structure has also been measured to allow for structural relaxation, considered to be mainly related to the swelling properties of the anionic polyacrylic coating pigment dispersant. The results illustrate the size-exclusion properties of the pore structure in relation to the material being absorbed and partial resistance to bulk penetration by pore wall adsorption in the case of oppositely charged species. The distribution of the absorbate throughout the pore network can be derived using mercury intrusion porosimetry and electron microscopy, and is deemed critical in respect to controlling the end performance properties, be they, for example, barrier, strength-enhancing applications, or both.

Abdel-Halim, E. S.; Al-Deyab, Salem S. Removal of heavy metals from their aqueous solutions through adsorption onto natural polymers // CARBOHYDRATE POLYMERS Volume: 84 Issue: 1 Pages: 454-458 Published: FEB 11 2011

Commercial sodium alginate was converted into water insoluble material through a very simple acidification treatment with alcoholic HCl solution. The so-obtained acidified sodium alginate (ASA) was found to exhibit complete water insolubility and to have a carboxyl content of 465 mequi./100 g sample. The ASA was used to remove Zn (II) ions from their aqueous solutions and different factors affecting the adsorption of Zn (II) ions onto ASA, like, pH, adsorbent dose, agitation time, and adsorbate concentration were extensively studied. Adsorption of Zn (II) ions onto ASA was found to be pH-dependent and maximum adsorption was obtained at pH 6. (C) 2010 Elsevier Ltd. All rights reserved.

Agirre, Amaia; Nase, Julia; Degrandi, Elise; et al. Miniemulsion Polymerization of 2-Ethylhexyl Acrylate. Polymer Architecture Control and Adhesion Properties //MACROMOLECULES Volume: 43 Issue: 21 Pages: 8924-8932 Published: NOV 9 2010

The feasibility of independent control of the gel fraction and sol molecular weight distribution in the miniemulsion polymerization of 2-ethylhexyl acrylate using symmetrical and nonsymmetrical cross-linkers and a chain transfer agent was investigated. It was found that the very reactive symmetrical crosslinker had only a limited effect on polymer architecture, whereas the nonsymmetrical cross-linker and the chain transfer agent had a profound effect allowing decoupling gel and sol molecular weight. Adhesive properties were mainly controlled by the gel content of the polymer.

Bandyopadhyay, Prasun; Ghosh, Amit K. Reversible Fluorescence Quenching by Micelle Selective Benzophenone-Induced Interactions between Brij Micelles and Polyacrylic Acids: Implications for Chemical Sensors // JOURNAL OF PHYSICAL CHEMISTRY B Volume: 114 Issue: 35 Pages: 11462-11467 Published: SEP 9 2010

The fluorescence response of pyrene has been studied in the presence of nonionic brij micelles and poly(acrylic acid) (PAA) with benzophenone (BP) as a neutral hydrophobic quencher. Pyrene emission is quenched ("off" state) in the presence of BP in brij 35 (polyoxyethylene-23-lauryl ether) and brij 56 (polyoxyethylene-10-cetyl ether) micelles. Quenched pyrene emission is selectively recovered ("on" state) for brij 35 micelles with the addition of PAA (starting conc 2.0 x 10(-5) M). Due to the interaction of PAA and brij 35 micelles and the relatively easier accessibility of PAA polymer chains near the bulky polyoxyethylene chain of brij 35 micelles, the chances of BP partition inside the hydrophobic polymer coil are more compared to brij 56 micelles. The PAA sensing ability of the "brij 35:pyrene:BP" system is dependent on the molecular weight (M) of the polymer. Fluorescence recovery has been observed with PAA (M similar to 150000) and complete recovery has been recorded with high M of PAA (M similar to 450000); however, no fluorescence change is observed in the presence of low M of PAA (M similar to 2000). In solution, such selective reversible fluorescence quenching has the potential for a new class of highly sensitive chemical sensor systems.

Borowko, M.; Sokolowski, S.; Staszewski, T. Adsorption of oligomers on the polymer-tethered surfaces //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 356 Issue: 1 Pages: 267-276 Published: APR 1 2011

A density functional study of adsorption of oligomers on weakly attractive surfaces modified with grafted chains is presented. The chain molecules are modeled as freely jointed tangent spheres. The segments interact via Lennard-Jones (12-6) potentials. Two types of substrates are considered - a neutral surface and the Lennard-Jones (9,3) surface. The mechanism of adsorption is discussed. Depending on the system characteristics, the primary, secondary and ternary adsorption is found. The effects of selected factors on adsorption and separation of mixtures are analyzed. (C) 2011 Elsevier Inc. All rights reserved.

Cai, Guo-Bin; Zhao, Gui-Xia; Wang, Xiang-Ke; et al. Synthesis of Polyacrylic Acid Stabilized Amorphous Calcium Carbonate Nanoparticles and Their Application for Removal of Toxic Heavy Metal ions in Water // JOURNAL OF PHYSICAL CHEMISTRY C Volume: 114 Issue: 30 Pages: 12948-12954 Published: AUG 5 2010

We report an efficient method for synthesis of poly(acrylic acid) stabilized amorphous calcium carbonate nanoparticles (ACC) and their application for removal of toxic heavy metal ions from aqueous solutions. The maxim removal capacities for Cd(2+), Pb(2+), Cr(3+), Fe(3+), and Ni(2+) ions were found to be 514.62 mg g(-1), 1028.21, 258.85, 320.5, and 537.2 mg g(-1), respectively. The distinguishing features of the ACC nanoparticles in water treatment involve not only high removal capacities, but also decontamination of trace ions. Approximately 83.0% on average removal can be achieved in the treatment of polluted water containing trace amount of radioactive Eu(3+) ions. A precipitation transformation mechanism is proposed to play a key role in such water treatment.

Cao, Jinxin; Pan, Xiaodi; Huang, Wei; et al. Synthesis of cationic poly(4-vinylpyridine)-functionalized colloidal particles by emulsion polymerization with reactive block copolymer for protein adsorption //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 381 Pages: 137-142 Published: SEP 1 2012

We report here a novel protein sequestration method using polymeric colloidal particles prepared by emulsion polymerization with reactive block copolymers. Specifically, poly(4-vinyl-N-ethylpyridine bromide)block-polymethylacrylate block copolymers were synthesized from reversible addition-fragmentation chain transfer polymerization and used as emulsifiers for emulsion polymerization of poly(4-vinyl-N-ethylpyridine bromide)-functionalized polymeric colloidal particles. The particles have high and stable zeta potentials when dispersed in solution, regardless of pH variations. As a result, the polymeric colloids demonstrate a high affinity for oppositely charged proteins, even though the isoelectric points of proteins may vary greatly. We show here that BSA can be sequestered highly efficiently with a maximum binding capacity (similar to 900 mg/g). The adsorbed protein is easily released, and the polymeric colloids are regenerated after washing with a buffer solution of high ionic strength. These properties may prompt this type of novel macromolecule-functionalized colloids to be utilized for effective protein adsorption and separation. (C) 2012 Elsevier Inc. All rights reserved.

Donnet, Marcel; Aimable, Anne; Lemaitre, Jacques; et al. Contribution of Aggregation to the Growth Mechanism of Seeded Calcium Carbonate Precipitation in the Presence of Polyacrylic Acid // JOURNAL OF PHYSICAL CHEMISTRY B Volume: 114 Issue: 37 Pages: 12058-12067 Published: SEP 23 2010

Our work investigates the precipitation mechanism of a seeded calcium carbonate reaction, by using cryogenic TEM to observe the early stages of the reaction. The early precipitation of a hydrated phase is proposed as an intermediate phase before transformation into calcite. Thermodynamic modeling in conjunction with pH, surface potential measurements, and colloidal stability modeling demonstrate that calcite growth is dominated by agglomeration. This is in agreement with the cryogenic TEM observations, which suggest oriented attachment dominates early aggregation. The final stage of the reaction is described by a ripening mechanism that is significantly inhibited when high concentrations of polyacrylic acid (PAA) are used. The different concentrations of PAA lead to significant differences in the final particle substructure observed using cross section TEM. At low PAA concentrations, single crystal particles result, coherent with the proposed early oriented attachment mechanism and interfacial energy calculations. A core shell model is proposed for high PAA concentrations, whereas internal ripening of nanosized pores has been observed for low PAA concentrations, suggesting trapped solvent during the rapid initial particle formation at the relatively high supersaturations (S = 30) investigated.

Dubacheva, Galina V.; Van der Heyden, Angeline; Dumy, Pascal; et al. Electrochemically Controlled Adsorption of Fc-Functionalized Polymers on beta-CD-Modified Self-Assembled Monolayers // LANGMUIR Volume: 26 Issue: 17 Pages: 13976-13986 Published: S

This work presents an in situ study of the adsorption/desorption behavior of ferrocene(Fc)-functionalized linear polymers on a gold surface covered with beta-cyclodextrin(beta-CD)-modified self-assembled monolayers (SAMs). The characterization of binary SAMs obtained with HS-(CH(2))(11)-EG(6)-N(3) and HS-(CH(2))(11)-EG(4)-OH (EG, ethylene glycol) was performed using a quartz crystal microbalance with dissipation monitoring (QCM-D), cyclic voltammetry, and contact angle measurements. The functionalization of SA Ms with beta-CD was made via the "click" reaction between the beta-CD monoalkyne derivative and azide groups exhibited by SA Ms. The formation of the host-guest complex between SAM-beta-CD and Fc-derivatized polymers (chitosan (CHI) and poly(allylamine hydrochloride) (PAH)) was studied by QCM-D. The viscoelastic model of Voinova was used to fit QCM-D curves recorded during the adsorption and electrochemically controlled desorption of CHI-Fc and PAH-Fc on SAM-beta-CD. Using QCM-D coupled to cyclic voltammetry, we demonstrated that CHI-Fc and PAH-Fc can be successfully deposited on a SAM-beta-CD-coated gold surface forming a stable multivalent inclusion complex between Fe moieties of polymer and beta-CD cavities of SAM. We also showed that all specifically attached polymer chains can be detached from the SAM-beta-CD-coated gold surface by applying an electric field. EP 7 2010

Feng Jing; Fu LiXue; Li JiHong; et al. Application of surface plasmon resonance in screening adsorbents and explaining adsorption phenomena using model polymers //CHINESE SCIENCE BULLETIN Volume: 55 Issue: 32 Pages: 3644-3647 Published: NOV 2010

A surface plasmon resonance (SPR) technique was developed as an online screening method to identify effective adsorbents for the peptide NH(2)-Cys-Thr-Trp-Trp-COOH (CW-4). To validate the SPR technique, several linear polymers containing amino acid residues were synthesized as models of their corresponding adsorbents. SPR screening of all the linear polymers demonstrated that the linear polymer containing phenylalanine residues (PPhe) exhibited the highest affinity for CW-4 among the polymers tested. In accordance with the screening results from SPR, the adsorbent containing phenylalanine (APhe) exhibited the highest adsorption capacity for CW-4. An interesting observation was that the amounts of CW-4 adsorbed on 3 adsorbents were quite small, even though both SPR and isothermal titration calorimetry (ITC) experiments indicated the presence of interactions between CW-4 and the three polymers. A kin etic analysis performed using SPR technology suggested such a phenomenon was ascribed to the poor stability of the CW-4/polymer complexes; that is, CW-4 associates with the polymers quickly, but it also dissociated quickly. The combined results suggested that SPR was a promising tool to identify the optimal adsorbent for peptides, analyze the interactions contributing to adsorption and explain adsorption phenomena using polymer models.

Feng, Jing; Fu, Li-Xue; Wang, Jun; et al. A comparison study between polymeric ligand and monomeric ligand for oligopeptide adsorption //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 355 Issue: 2 Pages: 478-485 Published: MAR 15 2011

This work aimed to compare two types of affinity ligands, i.e. polymeric and monomeric ligands, by investigating their adsorption affinity, capacity and selectivity to oligopeptide. The peptide NH(2)-VVRGCTWW-COOH (VW-8) was chosen as the target adsorbate, while histidine (His), aspartic acid (Asp), and leucine (Leu) were selected as the ligands, respectively. For each kind of ligand, both monomeric (M) and polymeric (P) forms were introduced onto the Sepharose matrix respectively to obtain the corresponding adsorbents. Both affinity tests using isothermal titration calorimetry (ITC) and adsorption capacities using static adsorption experiments indicated that the adsorbents with polymeric ligands (MX-P) exhibited better adsorption ability for VW-8 than the adsorbents with monomeric ligands (MX-M). In particular, the MX-PHis exhibited its affinity constant of 2.39 x 10(6) M(-1) and its adsorption capacity of 77.4 mg/g for VW-8, which was approximately 8-10 times higher than that of MX-MHis. Such distinct adsorption abilities between polymeric and monomeric ligands were interpreted based on nuclear magnetic resonance (NMR) and ITC data, and the results indicated that such better characters of polymeric ligands were ascribed to their good flexibility which facilitated the cooperative effects as well as the accessibility of ligands to the peptide. Additionally, the selective adsorption experiments indicated that all the adsorbents with polymeric ligands exhibited good selectivity to the peptide VW-8. (C) 2010 Elsevier Inc. All rights reserved.

Ghanem, Bader S.; Hashem, Mohammed; Harris, Kenneth D. M.; et al. Triptycene-Based Polymers of Intrinsic Microporosity: Organic Materials That Can Be Tailored for Gas Adsorption //MACROMOLECULES Volume: 43 Issue: 12 Pages: 5287-5294 Published: JUN 22 2010

We report the synthesis and properties of network polymers of intrinsic microporosity (network PIMs) derived from triptycene monomers that possess alkyl groups attached to their bridgehead positions. Gas adsorption can be controlled by the length and branching of the alkyl chains so that the apparent BET surface area of the materials can be tuned within the range 618-1760 m(2) g(-1). Shorter (e.g., methyl) or branched (e.g., isopropyl) alkyl chains provide the materials of greatest microporosity, whereas longer alkyl chains appear to block the microporosity created by the rigid organic framework. The enhanced microporosity, in comparison to other PIMs, originates from the macromolecular shape of the framework, as dictated by the triptycene units, which helps to reduce intermolecular contact between the extended planar struts of the rigid framework and thus reduces the efficiency of packing within the solid. The hydrogen adsorption capacities of the triptycene-based PIMs with either methyl or isopropyl substituents arc among the highest for purely organic materials at low or moderate presures (1.83% by mass at 1 bar/77K, 3.4% by mass at 18 bar/77 K). The impressive hydrogen adsorption capacity of these materials is related to a high concentration of subnanometre micropores, as verified by Horvath-Kawazoe analysis of low-pressure nitrogen adsorption data.

Glad, Brayden E.; Han, Chan; Kriven, Waltraud M. Polymer Adhesion to Geopolymer via Silane Coupling Agent Additives //JOURNAL OF THE AMERICAN CERAMIC SOCIETY Volume: 95 Issue: 12 Pages: 3758-3762 Published: DEC 2012

The effects of degree of cross-links on die adhesion properties of polydimethylsiloxane (PDMS) were investigated with the use of a point-contact method in air at room temperature. The degree of cross-links, rho, was varied in a wide range, inducing changes in the rheology of the cross-linked PDMS from viscous solution to elastic gel, and the adhesion properties were examined by changing the separation velocity under a constant normal load and waiting period prior to separation. As a result, the adhesion force, F(A), strongly depended on rho and showed a maximum at a characteristic rho around the loss tangent (tan delta) = 1. In addition, the shapes of the adhesion curves were found to depend strongly on rho, and they were categorized into four types. The different states of cross-linked polymers, i.e., elastic-gel type, weak-gel type, and solution type, showed the different shapes. In the case of the weak gel, two types of characteristic adhesion curves were obtained, which resulted from the different separation mechanisms with and without cavitations near the surface due to the interface and cohesive failures. In the intermediate range of rho. viscous or elastic fingering was detected, which resulted in the characteristic shape of the adhesion curve. The factors determining the type of the adhesion curves are discussed in terms of the microscopic surface, bulk properties, and the different shapes of the adhesive front it the contact surface.

He, Gui-Li; Messina, Rene; Loewen, Hartmut Statistics of polymer adsorption under shear flow //JOURNAL OF CHEMICAL PHYSICS Volume: 132 Issue: 12 Article Number: 124903 Published: MAR 28 2010

Using nonequilibrium Brownian dynamics computer simulations, we have investigated the steady state statistics of a polymer chain under three different shear environments: (i) linear shear flow in the bulk (no interfaces), (ii) shear vorticity normal to the adsorbing interface, and (iii) shear gradient normal to the adsorbing interface. The statistical distribution of the chain end-to-end distance and its orientational angles are calculated within our computer simulations. Over a wide range of shear rates, this distribution can be mapped onto a simple theoretical finite-extensible-nonlinear-elastic dumbbell model with fitted anisotropic effective spring constants. The tails of the angular distribution functions are consistent with scaling predictions borrowed from the bulk dumbbell model. Finally, the frequency of the characteristic periodic tumbling motion has been investigated by simulation as well and was found to be sublinear with the shear rate for the three setups, which extends earlier results done in experiments and simulations for free and tethered polymer molecules without adsorption

Hoshino, Jumpei; Limpanart, Sarintorn; Khunthon, Srichalai; et al. Adsorption of single-strand alkylammonium salts on bentonite, surface properties of the modified clay and polymer nanocomposites formation by a two-roll mill //MATERIALS CHEMISTRY AND PHYSICS Volume: 123 Issue: 2-3 Pages: 706-713 Published: OCT 1 2010

The adsorption of tallow alkylammonium salts onto bentonite from the Lopburi province in Thailand, and the effect of surface wettability on the formation of polymer-clay nanocomposites are reported. We looked specifically at octadecyltrimethyl ammonium chloride (S18), a popular member of the tallow alkylammonium salt family. The adsorption of 518 onto the bentonite interlayer can be divided into three distinct stages depending upon the initial concentration of S18. These stages are (a) monolayer formation, (b) intermediate state of double layer formation and (c) double layer formation. A decrease in surface energy driven by drops in the values of the polar and dispersive components was observed as the amount of surfactant surface coverage increased. Using thermal gravimetric analysis (TGA), the critical surface energy (CSE) of organoclay was found to decrease as the amount of absorbed S18 increased. S18 organoclay with different degrees of surface coverage was used in a two-roll mill to prepare high-density polyetheylene (HDPE)-clay nanocomposites. The oxidized polyethylene wax (OWax) was used as a dispersing agent to promote the delamination of the organoclay platelets. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) indicated a difference in the dispersing capability of the organoclay. (C) 2010 Elsevier B.V. All rights reserved.

Huang, Jianhan; Yuan, Bin; Wu, Xiaofei; et al. A comparative adsorption study of beta-naphthol on four polymeric adsorbents from aqueous solutions //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 380 Pages: 166-172 Published: AUG 15 2012

Adsorptive removal of aromatic compounds from aqueous solutions by polymeric adsorbents has attracted many concerns in recent years. A comparative adsorption study including equilibria, kinetics and column dynamics of beta-naphthol from aqueous solutions was carried out using two hypercrosslinked polymeric adsorbents (HJ-1 and TEPA) we developed and two commercial polymeric adsorbents (XAD-4 and XAD-7). The adsorption isotherms could be well described by the Freundlich equation, and the adsorption equilibrium capacities of beta-naphthol followed an order of q(e(TEPA)) > q(e(HJ-1)) > q(e(XAD-4)) > q(e(XAD-7)). The isosteric adsorption enthalpies on HJ-1 and TEPA decreased with increasing adsorption fractional loading, while a constant enthalpy was observed for XAD-4 and XAD-7, implying that HJ-1 and TEPA had a heterogeneous surface while XAD-4 and XAD-7 possessed a homogenous surface. The surface energetic heterogeneity of HJ-1 and TEPA could be well characterized by the Do's model. The adsorption kinetics were fitted by both pseudo-first-order and pseudo-second-order rate equations, and the intra-particle diffusion was found to be the rate-limiting step. The adsorption breakthrough data were well correlated by the Thomas and Clark models, and the dynamic capacities for TEPA, XAD-4 and XAD-7 adsorbents were calculated to be 341.7, 321.6, 268.0 and 173.8 mg/g dry resin, which were within 90% of the corresponding equilibrium capacities obtained in the batch experiments. (C) 2012 Elsevier Inc. All rights reserved.

Li, Zhiqiang; Greden, Karl; Alvarez, Pedro J. J.; et al. Adsorbed Polymer and NOM Limits Adhesion and Toxicity of Nano Scale Zerovalent Iron to E. coli //ENVIRONMENTAL SCIENCE & TECHNOLOGY Volume: 44 Issue: 9 Pages: 3462-3467 Published: MAY 1 2010

Nanoscale zerovalent iron (NZVI) is used for groundwater remediation. Freshly synthesized bare, i.e. uncoated NZVI is bactericidal at low mg/L concentration, but the impact of surface modifiers and aging (partial oxidation) on its bactericidal properties have not been determined. Here we assess the effect that adsorbed synthetic polymers and natural organic matter (NOM) and aging (partial oxidation) have on the bactericidal properties of NZVI to the gram-negative bacterium, Escherichia coli. Exposure to 100 mg/L of bare NZVI with 28% Fe(0) content resulted in a 2.2-log inactivation after 10 min and a 5.2-log inactivation after 60 min. Adsorbed poly(styrene sulfonate) (PSS), poly(aspartate) (PAP), or NOM on NZVI with the same Fe(0) content significantly decreased its toxicity, causing less than 0.2-log inactivation after 60 min. TEM images and heteroaggregation studies indicate that bare NZVI adheres significantly to cells and that the adsorbed polyelectrolyte or NOM prevents adhesion, thereby decreasing NZVI toxicity. The 1.8-log inactivation observed for bare NZVI with 7% Fe(0) content was lower than the 5.2-log inactivation using NZVI with 28% Fe(0) after 1 h; however, the minimum inhibitory concentration (MIC) after 24 h was 5 mg/L regardless of Fe(0) content. The MIC of PSS, PAP, and NOM coated NZVI were much higher: 500 mg/L, 100 mg/L, and 100 mg/L, respectively. But the MIC was much lower than the typical injection concentration used in remediation (10 g/L). Complete oxidation of Fe(0) in NZVI under aerobic conditions eliminated its bactericidal effects. This study indicates that polyelectrolyte coatings and NOM will mitigate the toxicity of NZVI for exposure concentrations below 0.1 to 0.5 g/L depending on the coating and that aged NZVI without Fe(0) is relatively benign to bacteria.

Malham, Ibrahim B.; Bureau, Lionel Density Effects on Collapse, Compression, and Adhesion of Thermoresponsive Polymer Brushes //LANGMUIR Volume: 26 Issue: 7 Pages: 4762-4768 Published: APR 6 2010

We probe, using the surface forces apparatus, the thermal response of poly(N-isopropylacrylamide) (PNIPAM) brushes of various grafting densities, grown from plasma-activated mica by means of surface-initiated polymerization. We thus show that dense thermoresponsive brushes collapse gradually as temperature is increased and that grafting density greatly affects their ability to swell: the swelling ratio of the brushes, which characterizes the thickness variation between the swollen and the collapsed state, is found to decrease from similar to 7 to similar to 3 as the number of grafted chains per unit area increases. Such a result, obtained with an unprecedented resolution in grafting density, provides qualitative support to calculations by Mendez et al. [Macromolecules 2005, 38, 174]. We further show that, in contrast to swelling, adhesion between two PNIPAM brushes appears to be rather insensitive to their molecular structure.

Matsuda, Ryotaro Design and Synthesis of Porous Coordination Polymers Showing Unique Guest Adsorption Behaviors // BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN Volume: 86 Issue: 10 Pages: 1117-1131 Published: OCT 15 2013

Gas storage and separation are becoming a high priority area of research due to economic, industrial, and environmental reasons. The last two decades have therefore witnessed dramatic growth in the search for more efficient and adaptable nanoporous materials. In particular, much attention has been focused on porous coordination polymers (PCPs) or metal organic frameworks (MOFs) as new nanoporous materials. Based on the unlimited combination of metal ions and organic ligands, PCPs can provide infinite variety of nanospace in their pores. As molecular adsorption is dependent on the size, shape, and surface nature of nanospace, many unique molecular adsorption or trapping phenomena have been reported in this class of compounds. In this account, I focus on how thoughtful design can lead to the synthesis of porous coordination polymers that demonstrate unprecedented adsorption behavior not found in other porous materials. Examples include selective adsorption of acetylene over carbon dioxide in the CPL series of PCPs, using charge-transfer to induce selective adsorption of nitric oxide and oxygen in TCNQ (7,7,8,8-tetracyano-p-quinodimethane) based PCP and light-induced on-demand adsorption and structural transformations in CID-based PCPs. The guidelines underpinning such unique, highly selective guest adsorption are discussed.

Menzies, Donna J.; Jasieniak, Marek; Griesser, Hans J.; et al. A ToF-SIMS and XPS study of protein adsorption and cell attachment across PEG-like plasma polymer films with lateral compositional gradients //SURFACE SCIENCE Volume: 606 Issue: 23-24 Pages: 1798-1807 Published: DEC 2012

In this work we report a detailed X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) study of poly(ethylene glycol) PEG-like chemical gradients deposited via plasma enhanced chemical vapour deposition (PECVD) at two different load powers using diethylene glycol dimethyl ether (DG) as a monomer. Principal component analysis (PCA) was applied to the ToF-SIMS data both before and after protein adsorption on the plasma polymer thin films. Results of the PCA loadings indicated a higher content of hydrocarbon fragments across the higher load power gradient, which adsorbed higher amounts of proteins. Gradients deposited at a lower load power retained a higher degree of monomer like functionality as did the central region directly underneath the knife edge electrode. Analysis of the adsorption of serum proteins (human serum albumin and fetal bovine serum) was monitored across the gradient films and increased with decreasing ether (PEG-like) film chemistries. The effect of protein incubation time on the levels adsorbed fetal bovine serum on the plasma polymer films was critical, with significantly more protein adsorbing after 24 hour incubation times on both gradient films. The attachment of HeLa cells on the gradients appeared to be dictated not only by the surface chemistry, but also by the adsorption of serum proteins. XPS analysis revealed that at surface ether concentrations of less than 70% in the gradient films, significant increases in protein and cell attachment were observed. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.

Mishra, Sumit; Rani, G. Usha; Sen, Gautam Microwave initiated synthesis and application of polyacrylic acid grafted carboxymethyl cellulose //CARBOHYDRATE POLYMERS Volume: 87 Issue: 3 Pages: 2255-2262 Published: FEB 14 2012

An environmentally benign and efficient route of synthesis of polyacrylic acid grafted carboxymethyl cellulose (CMC-g-PAA) is developed using microwave radiation alone to initiate the grafting reaction. The synthesis is optimized in terms of percentage grafting and intrinsic viscosity, by varying the microwave irradiation time and monomer (acrylic acid) concentration. The grafted product has been characterized by various physicochemical characterization techniques (intrinsic viscosity measurement. FTIR spectroscopy, SEM morphology study and elemental analysis). FTIR spectroscopy confirmed that free radicals are formed on polysaccharide backbone by cleavage of 1 degrees-OH bond, indicating microwave effect and not thermal decomposition as the cause of free radical generation. The application of the grafted product as flocculant for river water clarification, towards augmentation of drinking water supply has been investigated. (C) 2011 Elsevier Ltd. All rights reserved.

Montero-Pancera, Sabrina; Trouillet, Vanessa; Petershans, Andre; et al. Design of Chemically Activated Polymer Microwells by One-Step UV-Lithography for Stem Cell Adhesion //LANGMUIR Volume: 26 Issue: 3 Pages: 2050-2056 Published: FEB 2 2010

A novel method to produce sub-microwalled chemically activated polymer microwells by one-step UV-lithography under ambient conditions which are selectively coated with gelatin is introduced. The dimensions as well as the shape of the resulting polystyrene structures are both tunable merely by the irradiation time through one and the same mask. It is shown that the UV-irradiation initiates three effects at those surface areas which are not covered by the mask: (i) oxidation, (ii) cross-linking, and (iii) degradation of polystyrene. The superposition of those effects results in the formation of microscaled, oxidized polymer wells separated by polymer walls, whereas the polymer walls are formed Mow the mask structures. Topographical changes induced by the UV-irradiation are investigated by atomic force microscopy after different irradiation times. It is shown by X-ray photoelectron spectroscopy and ellipsometric investigations that the chemical composition of the irradiated areas and the degradation of polystyrene reach an equilibrium state after an irradiation time of 10 min. The lateral distribution of the cross-linked and oxidized and of the nonmodified polystyrene after irradiation was determined by fluorescence microscopy and time-of-flight secondary ion mass spectrometry. After the irradiated samples were treated with gelatin solution, it was found flat stein cells selectively attach to the irradiated areas. This is due to the selective immobilization of the gelatin oil the irradiated polymer areas, which was proved by X-ray photoelectron spectroscopy experiments.

Nambam, J. S.; Philip, John Competitive adsorption of polymer and surfactant at a liquid droplet interface and its effect on flocculation of emulsion //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 366 Issue: 1 Pages: 88-95 Published: JAN 15 2012

We investigate the competitive adsorption of polymer and surfactant at oil-water interface by measuring the hydrodynamic diameter, zeta potential, microstructure and rheology. The polymer used in our experiment is a statistical copolymer of polyvinyl alcohol and vinyl acetate copolymer (PVA-Vac) and the emulsion is oil-in-water system with an average droplet diameter of 200 nm. At low surfactant concentrations, the hydrodynamic diameter remains unchanged but above a critical aggregation concentration, it increases dramatically. The phase contrast optical microscopic images of emulsion droplets preadsorbed with polymers of higher molecular weight show a systematic increase in the floc size on increasing surfactant concentration due to biding of polymer-surfactant complexes on several droplets. The dramatic increase in zeta potential of the droplets on increasing ionic surfactant concentration clearly indicates a preferential adsorption of surfactant at the oil-water interface. The enhanced viscosity upon addition of ionic surfactant into polymers confirms the strong interaction between them. Our studies show that lower molecular weight polymers with suitable ionic surfactants can synergistically enhance the stability of formulations, while longer chain polymers induce bridging flocculation. Our results are useful for preparing oil-in-water formulations with long term stability. (C) 2011 Elsevier Inc. All rights reserved

O'Shea, John-Paul; Qiao, Greg G.; Franks, George V. Solid-liquid separations with a temperature-responsive polymeric flocculant: Effect of temperature and molecular weight on polymer adsorption and deposition //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 348 Issue: 1 Pages: 9-23 Published: AUG 1 2010

The effects of temperature and molecular weight of the temperature-responsive polymer, poly(N-isopropylacrylamide) (PNIPAM) were investigated in the solid-liquid separation of silica and alumina mineral particles. Suspensions dosed with PNIPAM at 25 degrees C were stable and did not settle. When the temperature was raised above the polymer lower critical solution temperature (LCST) (>32 degrees C), the suspensions were found to have high settling rates, large particle aggregate sizes and high suspension shear yield stresses (tau(y)). The sediment bed solids volume fraction (phi(f)), of these suspensions was found to increase after a temperature decrease below the polymer LCST and was attributed to a decrease in the attractive particle-particle interactions as shown by a corresponding decrease in shear yield stress, with decreasing temperature. Settling rates were found to increase with molecular weight when suspensions were dosed at 25 degrees C and settled at 50 degrees C. Increasing polymer molecular weight resulted in increased molecular polymer adsorption at 25 degrees C. Greater initial adsorbed amounts of polymer on the surface produced more nucleation sites for deposition of additional polymer as the temperature was increased from 25 degrees C to above the LCST where polymer phase separation occurred. When the polymer was dosed at 50 degrees C, the rate of sedimentation was very low. Under these conditions, the polymer molecules associate with each other to form polymer aggregates of typically 1250 nm diameter. These colloidal polymer aggregates do not readily deposit on the particles surfaces such that mineral particle aggregation does not readily occur. (C) 2010 Elsevier Inc. All rights reserved.

Palacio, Manuel L. B.; Bhushan, Bharat Enzyme adsorption on polymer-based confined bioinspired biosensing surface // JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A Volume: 30 Issue: 5 Article Number: 050607 Published: SEP 2012

Biosensor stability and performance are known to benefit from the nanoscale confinement of its immobilized protein or enzyme components due to its ability to mimic the natural environment of these biomolecules. In this study, the enzyme cholesterol oxidase (ChOx) was adsorbed on pores created on polystyrene-block-polymethyl methacrylate films. A combination of fluorescence microscopy and atomic force microscopy analysis reveals the presence of ChOx on the polystyrene domain pores. Absorbance measurements on a cholesterol solution exposed to the enzyme deposited on the block copolymer reveal the occurrence of catalysis. The results of this study demonstrate the feasibility of immobilizing enzymes in a polymer-derived bioinspired platform that can be utilized for biosensing applications. (C) 2012 American Vacuum Society. [http://dx.doi.org/10.1116/1.4745852]

Potapova, E.; Grahn, M.; Holmgren, A.; et al. The effect of polymer adsorption on the wetting properties of partially hydrophobized magnetite//JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 367 Pages: 478-484 Published: FEB 1 2012

Upon reverse flotation of iron ore, the surface of the iron ore concentrate may become partially hydrophobized due to adsorption of flotation collector, which is facilitated by the calcium ions present in the process water. Hydrophobic areas on the concentrate surface may introduce problems in subsequent pelletization of the concentrate. A possible way to restore the wettability of the surface could be by modifying the surface with a hydrophilic polymer. The effect of hydrophilic polymers of different types, viz. cationic, anionic, and non-ionic, on the wettability of the magnetite surface after adsorption of a surfactant was investigated. Although all the polymers could adsorb on magnetite at pH 8.5, the contact angle measurements revealed that only anionic ammonium polyacrylate could decrease the contact angle of synthetic magnetite after surfactant adsorption to a level close to that of as-synthesized magnetite. Such effect was probably achieved due to shielding of the hydrophobic surfactant chains from the aqueous phase by hydrophilic polyacrylate molecules. The fact that polyacrylate adsorption on magnetite occurred via calcium ions makes polyacrylate suitable for application in calcium-rich process water. The results presented in this work illustrate that ammonium polyacrylate could be successfully used to improve the wettability of magnetite after adsorption of surfactants. (C) 2011 Elsevier Inc. All rights reserved.

Riccardi, E.; Wang, J. -C.; Liapis, A. I. A molecular dynamics study on the transport of a charged biomolecule in a polymeric adsorbent medium and its adsorption onto a charged ligand //JOURNAL OF CHEMICAL PHYSICS Volume: 133 Issue: 8 Article Number: 084904 Published: AUG 28 2010

The transport of a charged adsorbate biomolecule in a porous polymeric adsorbent medium and its adsorption onto the covalently immobilized ligands have been modeled and investigated using molecular dynamics modeling and simulations as the third part of a novel fundamental methodology developed for studying ion-exchange chromatography based bioseparations. To overcome computational challenges, a novel simulation approach is devised where appropriate atomistic and coarse grain models are employed simultaneously and the transport of the adsorbate is characterized through a number of locations representative of the progress of the transport process. The adsorbate biomolecule for the system studied in this work changes shape, orientation, and lateral position in order to proceed toward the site where adsorption occurs and exhibits decreased mass transport coefficients as it approaches closer to the immobilized ligand. Furthermore, because the ligands are surrounded by counterions carrying the same type of charge as the adsorbate biomolecule, it takes the biomolecule repeated attempts to approach toward a ligand in order to displace the counterions in the proximity of the ligand and to finally become adsorbed. The formed adsorbate-ligand complex interacts with the counterions and polymeric molecules and is found to evolve slowly and continuously from one-site (monovalent) interaction to multisite (multivalent) interactions. Such a transition of the nature of adsorption reduces the overall adsorption capacity of the ligands in the adsorbent medium and results in a type of surface exclusion effect. Also, the adsorption of the biomolecule also presents certain volume exclusion effects by not only directly reducing the pore volume and the availability of the ligands in the adjacent regions, but also causing the polymeric molecules to change to more compact structures that could further shield certain ligands from being accessible to subsequent adsorbate molecules. These findings have significant practical implications to the design and construction of polymeric porous adsorbent media for effective bioseparations and to the synthesis and operation of processes employed in the separation of biomolecules. The modeling and analysis methods presented in this work could also be suitable for the study of biocatalysis where an enzyme is immobilized on the surface of the pores of a porous medium. (C) 2010 American Institute of Physics. [doi:10.1063/1.3473930

Rychlewski, G.; Whittington, S. G. Self-avoiding Walks and Polymer Adsorption: Low Temperature Behaviour //JOURNAL OF STATISTICAL PHYSICS Volume: 145 Issue: 3 Special Issue: SI Pages: 661-668 Published: NOV 2011

We give a brief review of the self-avoiding walk model of polymer adsorption highlighting some open problems in the area. We then discuss the low temperature behaviour and derive some results about the behaviour of the free energy at low temperatures.

Sakai, Kenichi; Izumi, Keiko; Sakai, Hideki; et al. Polymerizable gemini surfactants at solid/solution interfaces: Adsorption and polymerization on melamine formaldehyde particles and capsule fabrication //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 343 Issue: 2 Pages: 491-495 Published: MAR 15 2010

Organic capsules have been fabricated via three steps, by using the polymerizable gemini surfactant (1,2-bis(dimethyl(11-methacryloyloxy)undecylammonio) hexane dibromide, PC11-6-11) as a single wail component. In the first fabrication step, the surfactant spontaneously adsorbs on acid-dissolvable melamine formaldehyde (MF) particles in aqueous media. The adsorption isotherm data reveal that the adsorbed amount of PC11-6-11 (per chain) is greater than that of the corresponding monomeric surfactant ((11-methacryloyloxy)undecyltrimethylammonium bromide, PC11), resulting from the greater intermolecular association of PC11-6-11 at the solid/solution interface. The closely packed adsorbed layer of PC11-6-11 provides an opportunity to give a polymer thin film, as a result of in situ photo-polymerization on MF particles (in the second fabrication step) and subsequent acid dissolution of the core MF particles (in the third fabrication step). The dynamic light scattering (DLS) measurements have shown that the apparent hydrodynamic diameter of PC11-6-11 capsules is reversibly changed in response to a change in ionic strength: the increased background electrolyte concentration results in deswelling of the capsules, and vice versa. It seems likely that this swelling/deswelling behavior is primarily driven by the electrostatic interaction between quaternary ammonium groups within the polymerized film. We have also studied the capture and release capabilities of glucose into/from the capsule core and found that (i) glucose is encapsulated into the capsule core at high electrolyte concentrations and (ii) the glucose molecules encapsulated into the core are gradually released when the outer electrolyte solution is replaced by pure water. We believe, therefore, that the PC11-6-11 capsules fabricated here are useful as stimulus-responsive smart vehicles. (C) 2009 Elsevier Inc. All rights reserved.

Sakasegawa, Daisuke; Tsuzuki, Takeshi; Sugizaki, Yoshiki; et al. Effects of Degree of Cross-Links on Adhesion Curves of Cross-Linked Polymers Observed by a Point-Contact Method //LANGMUIR Volume: 26 Issue: 8 Pages: 5856-5863 Published: APR 20 2010

The effects of degree of cross-links on die adhesion properties of polydimethylsiloxane (PDMS) were investigated with the use of a point-contact method in air at room temperature. The degree of cross-links, rho, was varied in a wide range, inducing changes in the rheology of the cross-linked PDMS from viscous solution to elastic gel, and the adhesion properties were examined by changing the separation velocity under a constant normal load and waiting period prior to separation. As a result, the adhesion force, F(A), strongly depended on rho and showed a maximum at a characteristic rho around the loss tangent (tan delta) = 1. In addition, the shapes of the adhesion curves were found to depend strongly on rho, and they were categorized into four types. The different states of cross-linked polymers, i.e., elastic-gel type, weak-gel type, and solution type, showed the different shapes. In the case of the weak gel, two types of characteristic adhesion curves were obtained, which resulted from the different separation mechanisms with and without cavitations near the surface due to the interface and cohesive failures. In the intermediate range of rho. viscous or elastic fingering was detected, which resulted in the characteristic shape of the adhesion curve. The factors determining the type of the adhesion curves are discussed in terms of the microscopic surface, bulk properties, and the different shapes of the adhesive front it the contact surface.

Sharma, Manish K.; Senkovska, Irena; Kaskel, Stefan; et al. Three-Dimensional Porous Cd(II) Coordination Polymer with Large One-Dimensional Hexagonal Channels: High Pressure CH4 and H-2 Adsorption Studies // INORGANIC CHEMISTRY Volume: 50 Issue: 2 Pages: 539-544 Published: JAN 17 2011

A new porous and hydrothermally stable three-dimensional (3D) coordination polymer {[Cd(bpydb)]center dot 6H(2)O}(n) (1) has been synthesized under solvothermal condition from a new rigid ligand 4,4'-(4,4'-bipyridine-2,6-diyl) dibenzoic acid (H(2)bpydb) and Cd(NO3)(2)center dot 6H(2)O. Single crystal X-ray analysis shows that 1 has a 5-connected 4(4)6(6) vma net with one-dimensional (1D) hexagonal channels filled with water molecules. Integrity of the framework is maintained upon removal of the water molecules by heating to result in a porous framework. Low pressure N-2 and high pressure H-2 and CH4 sorption studies along with water adsorption studies were performed on this framework.

Uemura, Kazuhiro; Yamasaki, Yukari; Onishi, Fumiaki; et al. Two-Step Adsorption on Jungle-Gym-Type Porous Coordination Polymers: Dependence on Hydrogen-Bonding Capability of Adsorbates, Ligand-Substituent Effect, and Temperature //INORGANIC CHEMISTRY Volume: 49 Issue: 21 Pages: 10133-10143 Published: NOV 1 2010

A preliminary study of isopropanol (IPA) adsorption/desorption isotherms on a jungle-gym-type porous coordination polymer, [Zn(2)(bdc)(2)(dabco)](n) (1, H(2)bdc = 1,4-benzenedicarboxylic acid, dabco =1,4-diazabicydo[2.2.2]octane), showed unambiguous two-step profiles via a highly shrunk intermediate framework The results of adsorption measurements on 1, using probing gas molecules of alcohol (MeOH and EtOH) for the size effect and Me(2)CO for the influence of hydrogen bonding, show that alcohol adsorption isotherms are gradual two-step profiles, whereas the Me(2)CO isotherm is a typical type-I isotherm, indicating that a two-step adsorption/desorption is involved with hydrogen bonds. To further clarify these characteristic adsorption/desorption behaviors, selecting nitroterephthalate (bdc-NO(2)), bromoterephthalate (bdc-Br), and 2,5-dichloroterephthalate (bdc-Cl(2)) as substituted dicarboxylate ligands, isomorphous jungle-gym-type porous coordination polymers, {[Zn(2)(bdc-NO(2))(2)(dabco)] center dot solvents), (2 superset of solvents), {[Zn(2)(bdc-Br)(2)(dabco)] center dot solvents}(n) (3 superset of solvents), and {[Zn(2)(bdc-Cl(2))(2)(dabco)] solvents) (4 superset of solvents), were synthesized and characterized by single-crystal X-ray analyses. Thermal gravimetry, X-ray powder diffraction, and N(2) adsorption at 77 K measurements reveal that [Zn(2)(bdc-NO(2))(2)(dabco)(n), (2), [Zn(2)(bdc-Br)(2)(dabco)](n) (3), and [Zn(2)(bdc-Cl(2))(2)(dabco)](n) (4) maintain their frameworks without guest molecules with Brunauer-Emmett-Teller (BET) surface areas of 1568 (2), 1292 (3), and 1216 (4) m(2) g(-1). As found in results of MeOH, EtOH, IPA, and Me(2)CO adsorption/desorption on 2-4, only MeOH adsorption on 2 shows an obvious two-step profile. Considering the substituent effects and adsorbate sizes, the hydrogen bonds, which are triggers for two-step adsorption, are formed between adsorbates and carboxylate groups at the corners in the pores, indudng wide pores to become narrow pores. Interestingly, such a two-step MeOH adsorption on 2 depends on the temperature, attributed to the small free-energy difference (Delta F(host)) between the two guest-free forms, wide and narrow pores.

Uenlue, Murat; Abbott, Daniel; Ramaswamy, Nagappan; et al. Analysis of Double Layer and Adsorption Effects at the Alkaline Polymer Electrolyte-Electrode Interface //JOURNAL OF THE ELECTROCHEMICAL SOCIETY Volume: 158 Issue: 11 Pages: B1423-B1431 Published: 2011

In this study, the performance of the anionic electrodes in polymer-based alkaline fuel cells is analyzed. Direct alcohol, alkaline fuel cells suffer from a rapid decrease in cell potential at low discharge currents. Several effects are described to account for this drop in cell potential. Quaternary ammonium ions can specifically adsorb on the catalyst surface decreasing the active surface area and lowering the rate of methanol oxidation. In addition, the tethering of the quaternary ammonium cations on the polymer electrolyte inhibits the cation mobility causing a diffuse double layer to be formed. The diffuse double layer electrostatically inhibits the migration of hydroxide to the surface of the electrode which is needed for alcohol oxidation. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.075111jes] All rights reserved.

Umoren, S. A.; Li, Y.; Wang, F. H Effect of aluminium microstructure on corrosion and inhibiting effect of polyacrylic acid in H2SO4 solution //JOURNAL OF APPLIED ELECTROCHEMISTRY Volume: 41 Issue: 3 Pages: 307-315 Published: MAR 2011

The corrosion behaviour of a microcrystalline aluminium (mc-Al) coating fabricated from pure cast aluminium substrate by magnetron sputtering and the pure polycrystalline aluminium (pc-Al) were studied using electrochemical impedance spectroscopy and potentiodynamic polarization techniques in aerated 0.5 M H2SO4 at 30 +/- A 1 A degrees C. The corrosion inhibiting effect of polyacrylic acid (PAA) and synergistic effect of iodide ions was also investigated. Results obtained show that surface microcrystallization increases the corrosion susceptibility of pure cast aluminium leading to decrease in interfacial impedance and an increase in the kinetics of the anodic dissolution. Introduction of PAA into the corrosive medium was observed to retard the corrosion rates of both specimens. The inhibition mechanism was affected by the microstructure of the sample. PAA functions as a mixed inhibitor but under cathodic control for pc-Al and under anodic control for mc-Al. Addition of iodide ions synergistically increased the inhibition efficiency of PAA and this effect was more pronounced with mc-Al.

Wang, Y.; Deen, I.; Zhitomirsky, I. Electrophoretic deposition of polyacrylic acid and composite films containing nanotubes and o xide particles //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 362 Issue: 2 Pages: 367-374 Published: OCT 15 2011

Electrophoretic deposition (EPD) method has been developed for the deposition of thin films of polyacrylic acid (PAA). This method allowed the formation of uniform films of controlled thickness on conductive substrates. It was shown that PAA can be used as a common dispersing agent suitable for charging and EPD of various materials, such as multiwalled carbon nanotubes, halloysite nanotubes, MnO(2), NiO, TiO(2) and SiO(2). The feasibility of EPD of composite films containing the nanotubes and oxide particles in a PAA matrix has been demonstrated. The kinetics of deposition and deposition mechanisms were investigated and discussed. The films were studied by thermogravimetric analysis, differential thermal analysis, X-ray diffraction and scanning electron microscopy. The results indicated that film thickness and composition can be varied. Obtained results pave the way for the fabrication of PAA and composite films for biomedical, electrochemical and other applications. (C) 2011 Elsevier Inc. All rights reserved.

Yiapanis, George; Henry, David J.; Evans, Evan; et al. Simulations of Nanoindentation of Polymer Surfaces: Effects of Surface Cross-Linking on Adhesion and Hardness //JOURNAL OF PHYSICAL CHEMISTRY C Volume: 114 Issue: 1 Pages: 478-486 Published: JAN 14 2010

We present a simulation methodology to chemically cross-link the surface of fully atomistic models of polymers. We simulated nanoindentation of the cross-linked model surfaces whereby nanoparticles (fullerene in this case) are used to probe different regions of the polymer surface enabling us to characterize the surface hardness of the polymer film and calculate the work of adhesion between polymer and nanoparticle. The cross-linked polyester surfaces are constructed using hexamethylene and isophorone di-isocyanate cross-linkers. Our results indicate that, despite surface cross-linking with hexamethylene di-isocyanate molecules, the polymer top surface still maintains significant softness. The hexamethylene cross-links that protrude from the Surface are deformable, resulting in a strong adhesion between the Surface and carbon particle. In contrast, isophorone Surface cross-linking results in significantly weaker adhesion with carbon, due to the less deformable rigid structure formed at the top layer. In this case, while rigidity is imparted to the polymer top surface, the flexibility of the core region of the polymer is maintained.

Zanini, Stefano; Riccardi, Claudia; Grimoldi, Elisa; et al. Plasma-induced graft-polymerization of polyethylene glycol acrylate on polypropylene films: Chemical characterization and evaluation of the protein adsorption //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 341 Issue: 1 Pages: 53-58 Published: JAN 1 2010

This work deals with the optimization of argon plasma-induced graft-polymerization of polyethylene glycol acrylate (PEGA) on polypropylene (PP) films in order to obtain Surfaces with a reduced protein adsorption for possible biomedical applications. To this end, we examined the protein adsorption on the treated and untreated Surfaces. The graft-polymerization process consisted of four steps: (a) plasma pre-activation of the PP Substrates: (b) immersion in a PEGA solution: (c) argon plasma-induced graft-polymerization; (d) washing and drying of the samples. The efficiency of these processes was evaluated in terms of the amount of grafted polymer, coverage uniformity and Substrates wettability. The process was monitored by contact angle measurements, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS) and atomic force microscopy (AFM) analyses. The stability of the obtained thin films was evaluated in water and in Phosphate Buffer Saline (PBS) at 37 degrees C. The adsorption of fibrinogen and green fluorescent protein (GFP) - taken as model proteins - on the differently prepared surfaces was evaluated through a fluorescence approach using laser scanning confocal microscopy with photon counting detection. After plasma treatments of short duration, the protein adsorption decreases by about 60-70% with respect to that of the untreated film, while long plasma exposure resulted in a higher protein adsorption, due to damaging of the grafted polymer. (C) 2009 Elsevier Inc. All rights reserved

Zdziennicka, Anna; Janczuk, Bronislaw Behavior of cationic surfactants and short chain alcohols in mixed surface layers at water-air and polymer-water interfaces with regard to polymer wettability. I. Adsorption at water-air interface //JOURNAL OF COLLOID AND INTERFACE SCIENCE Volume: 349 Issue: 1 Pages: 374-383 Published: SEP 1 2010

Measurements of the surface tension of aqueous solutions were carried out at 293 K for mixtures of cetyltrimethylammonium bromide (CTAB) with short chain alcohols such as methanol and ethanol, as well as for 1-hexadecylpyridinium bromide (CPyB) with the same alcohols. The concentration of CTAB and CPyB in aqueous solutions was in the range from 10(-5) to 10(-3) M, and methanol and ethanol was in the range from 0 to 21.1M and from 0 to 11.97 M, respectively. moreover, the surface tension of aqueous solution mixtures of cationic surfactants with propanol in the concentration range from 0 to 6.67 M was also taken into consideration. The obtained isotherms of the surface tension were compared to those calculated from the Szyszkowski and Connors equations. The constants in these equations were determined by the least squares method. It appeared that they depended on the type of surfactant and alcohol. From comparison of the experimental and theoretical isotherms of the surface tension it is possible, at first approximation, to describe the relationship between the surface tension of aqueous solutions of cationic surfactants with short chain alcohol mixtures as a function of alcohol molar fraction in the bulk phase by the Szyszkowski and Connors equations. Furthermore, changes of the surface tension of aqueous solutions of CTAB and CPyB with alcohol mixtures at each constant concentration of cationic surfactant can be predicted by the Fainerman and Miller equation, if it is possible to determine the molar area of cationic surfactant and alcohol in the mixed monolayer. Based on the surface tension isotherms the Gibbs surface excess concentration of cationic surfactants and alcohols at water-air interface was determined, and in the case of alcohol, this concentration excess was recalculated for that of Guggenheim-Adam. The Guggenheim-Adam surface excess concentration was applied for determination of the real concentration of alcohol in the mixed surface monolayer. The real concentration of cationic surfactant was assumed equal to Gibbs surface excess concentration. For determination of the composition of the surface layer, its proper thickness was assumed. The composition of the surface mixed monolayer was discussed with regard to the standard free energy of cationic surfactant and alcohol adsorption at water-air interface determined in different ways. The standard free energy of adsorption of "pure" cationic surfactants determined from the Langmuir and Aronson and Rosen equations was compared to that deduced on the basis of Cp(20), and the surface tension of the cationic surfactant tail and tail-water interface tension. (C) 2010 Elsevier Inc. All rights reserved.

Zhang, Yan-Juan; Liu, Tao; Kanegawa, Shinji; et al Interconversion between a Nonporous Nanocluster and a Microporous Coordination Polymer Showing Selective Gas Adsorption //JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Volume: 132 Issue: 3 Pages: 912-+ Published: JAN 27 2010

Using reversible polymerization and depolymerization reactions in a single crystal state, we achieved a reversible transformation from a naonocluster to a coordination polymer During the interconversion. the structural frameworks switched between nonporous hexanuclear clusters and porous double-zigzag chains; the magnetic behaviors switched between paramagnetism and metamagnetism, respectively. The microporous framework, which had 1D channels 1.9 angstrom x 3.6 angstrom in size, exhibited selective as adsorption of H(2) and CO(2) over N(2).

Zhang, Zhian; Zeng, Tao; Lu, Hai; et al. Enhanced High-Temperature Performances of LiFePO4 Cathode with Polyacrylic Acid as Binder //ECS ELECTROCHEMISTRY LETTERS Volume: 1 Issue: 5 Pages: A74-A76 Published: 2012

The electrochemical performance of LiFePO4 at elevated temperature (55 degrees C) is enhanced by using polyacrylic acid (PAA) as a binder. Results show that at 55 degrees C, it can deliver 100 cycles with 97.7% capacity retention and unchanged discharge plateau potential at the current density of 70 mA g(-1) (0.5 C), which is much better than the cathode with polyvinylidene fluoride. Scanning electron microscopy studies clearly demonstrate that glue-like PAA coating on the electrodes form a protective film, which may protect the LiFePO4 matrix from the corrosive solution or suppress the dissolution of Fe. (C) 2012 The Electrochemical Society. All rights reserved.

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