Self-Assembled Quaternary Ammonium-Containing Comb-Like Polyelectrolytes for the Hydrolysis of Organophosphorous Esters: Effect of Head Groups and Counter-Ions.

The aim of this work was to increase the efficiency of catalytic systems for the hydrolytic cleavage of 4-nitrophenyl esters of phosphonic acids. Quaternary ammonium-containing comb-like polyelectrolytes («polymerized micelles¼) with ester cleavable fragments and a low aggregation threshold were used as catalysts. The synthesis of poly(11-acryloyloxyundecylammonium) surfactants with different counterions (Br- , NO3- , CH3 C6 H4 SO3- ) and head groups was realized by micellar free-radical polymerization. Molecular weight, critical association concentration, particle sizes and solubilization properties toward Orange OT were determined. Self-assemblies organized by poly(11-acryloyloxyundecyltrimethyl ammonium) bromide successfully catalyze the hydrolysis of 4-nitrophenyl butylchloromethylphosphonate up to two orders of magnitude compared to aqueous alkaline hydrolysis. The development of these catalysts is promising for industrial applications and organophosphorus compound detoxification.

Poly(D,L-lactide)/PEG blend films for keratinocyte cultivation and skin reconstruction.

The objective of this study was to develop a novel porous thin poly(D,L-lactide) (PLA) film as a tissue-engineering scaffold for keratinocytes used for the replacement of damaged skin. Poly(D,l-lactic acid)/poly(ethylene glycol) (PEG: Mw 6000 or 15 000) blend films were formed by a spin coating technique. The properties and structures of these blend films were investigated. PDLA/PEG (6000) blend films were modified by microfibrillar collagen after water incubation to increase hydrophilicity and improve keratinocyte adhesion. Primary keratinocytes were seeded on PLA films, cultivated for 9 d and transplanted to rats with a model skin defect wound. The wound's healing after keratinocyte transplantation was assayed with histological and immunochemical methods. It was found that skin damage recovery was the most effective after transplantation of keratinocytes on porous PLA film modified with collagen.

Novel surfactant-selective membrane electrode based on polyelectrolyte-surfactant complex.

Novel class of active ionophores for surfactant selective electrodes is proposed. PVC membrane doped with polyelectrolyte-surfactant stoichiometric complex is used for ion-selective electrode construction responsive to cetyltrimethyl ammonium bromide and related surfactants. New ionophore is quite stable and completely insoluble in aqueous media in wide range of pH. The electrode displays nearly Nernstian slope in CTAB concentration range 10(-6)-10(-3)M. Polyelectrolyte platform allows to design wide range of different ionophores responsive to cationic organic substances.