Polyaniline/Maleic Acid Copolymers Composites: Synthesis and Characterization

Summary: Polyaniline/maleic acid copolymers composites were synthesized by chemical in situ polymerization of aniline using ammonium peroxidisulfate as oxidant, in the presence of water soluble copolymers containing carboxylic groups. Fine dispersions of composite materials, soluble in N,N-dimethylformamide or dimethyl sulfoxide were obtained which can be processed as thin films and membranes for application as proton-conductive materials for electrolyte membranes of fuel cells. The composites were characterized by FTIR spectroscopy and thermal methods.     

Neutron Reflectometry Studies of ZnO Films

Textured Al-doped ZnO films are studied using neutron reflectometry. The films are quasiperiodic structures with a period of several nanometers. The films are inhomogeneous in a surface layer with a thickness of 10–20 nm.     

Supramolecular Systems from Natural Polymers and Maleic Polyelectrolytes

Summary: The formation of polyelectrolyte complexes by interaction between chitosan and maleic acid copolymers as strong/weak dibasic polyanions was investigated. The interaction between the sodium salt of maleic acid copolymers with styrene or vinyl acetate and the chitosan hydrochloride in aqueous solution was followed by potentiometric, conductometric and turbidimetric titration. The effect of the added low molecular salt on the complex formation was also investigated. The precipitated complexes were analyzed by FTIR spectroscopy and TG analysis. Preliminary layer-by-layer deposition experiments were performed to obtain thin films.     

Aggregation and protein binding of sodium maleate copolymers with varying hydrophobicities

Copolymers of sodium maleate with methyl methacrylate, styrene, or vinyl acetate have been synthesized and studied in aqueous NaCl solutions of various ionic strengths. The polymers are polyelectrolytes with varying hydrophobicities, and their solution properties have been studied using static and dynamic light scattering. Copolymers containing methyl methacrylate or styrene were shown to aggregate in water upon increasing salt concentration. Copolymers of sodium maleate and vinyl acetate do not associate with increasing ionic strength. The binding of bovine serum albumin and cytochrome C to the sodium maleate copolymers was also investigated by light scattering. It was observed that cytochrome C forms complexes with the copolymers containing methyl methacrylate or vinyl acetate whereas albumin does not bind to any of the copolymers studied. Copyright © 2004 John Wiley & Sons, Ltd.     

Multifunctional,water‐soluble,C60‐pendant maleic anhydride copolymer

Starting from the synthesis of a new methanofullerene derivative bearing an alcohol group, we report on the preparation of a water‐soluble, fullerene‐pendant copolymer. This multifunctional, C₆₀‐pendant maleic anhydride copolymer was characterized by conductometric titration, Fourier transform infrared and ultraviolet spectroscopy, thermogravimetric analysis, and cyclic voltammetry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5814–5822, 2005     

Potential drug delivery systems from maleic anhydride copolymers and phenothiazine derivatives

New functionalized derivatives of phenothiazine containing amino or hydroxy groups with potential pharmacological properties were synthesized and characterized. They were reacted with maleic anhydride copolymers in order to obtain conjugates which can be used as controlled-release systems.     

Interaction of Maleic Acid Copolymers with Collagen

One of the present trends to increase the efficiency of the chrome tanning process is the use of chemicals which change the affinity and induce a better binding of the chromium ions in the hides. Recently, some anionic polyelectrolytes based on poly(acrylic acid) or maleic acid copolymers were developed as additives in the chrome tanning. The effect of polyelectrolytes could be explained by their interaction with the collagen from hide. In our work four maleic acid copolymer/collagen systems were investigated by turbidimetric, conductometric and potentiometric titrations. The interaction between the two macromolecular compounds was clearly evidenced, and its dependence on the chemical structure of the maleic acid copolymer and on the amount of added chromium ions was studied. Homogeneous systems or turbid dispersions were observed depending on the hydrophilic or hydrophobic character of the maleic copolymer, on the [CH]/[MP] ratio, and on the concentration of the chromium ions.     

Association of cationic surfactants with maleic acid copolymers: dependence of binding on the nature of the neutral comonomer unit

Isotherms of binding of dodecylpyridinium chloride (DPC) and cetylpyridinium chloride (CPC) by copolymers of maleic acid (MA; degree of neutralization=1) with methyl methacrylate (MMA), styrene (St), and vinyl acetate (VA) were determined at various salt concentrations by using the potentiometric technique. The average composition of copolymers corresponds to designations MA(MMA)3, MASt, and MAVA. Very different binding behavior has been found. The cooperativity parameter, u, for binding to MA(MMA)3 is the lowest and displays no dependence on ionic strength, which is a consequence of significant hydrophobic polymer-surfactant interactions. Isotherms for the DPC/MASt system display a two-step binding mechanism, which could not be clearly identified in the CPC/MASt case, presumably due to interference of surfactant micellization with the second step. It is proposed that the first step of binding in DPC/MA(MMA)3 and in DPC/MASt solutions is of electrostatic origin, as is the second step in DPC/MASt. On the contrary, the second step in DPC/MA(MMA)3 is mostly due to hydrophobic interactions of surfactant hydrocarbon tails with the predominantly uncharged DPC/MA(MMA)3 complex. MAVA solutions display the highest critical aggregation concentration (cac) values, which show a slight decreasing trend with increasing ionic strength. The very compact form of the MAVA copolymer at high salt content was responsible for this.