Combination of episulfide ring-opening polymerization with ATRP for the preparation of amphiphilic block copolymers.

We report for the first time the combination of ATRP and ring-opening episulfide polymerization as a means to synthesize polysulfide-based low-dispersity amphiphilic block copolymers. The most significant finding is the possibility to perform ATRP under mild conditions using poly(propylene sulfide) macroinitiators, apparently without any significant copper sequestration by the polysulfides. Using glycerol monomethacrylate (GMMA) as a hydrophilic monomer, the polymers self-assembled in colloidal structures with a morphology depending on the PS/GMMA ratio, but also probably on GMMA degree of polymerization.

Advantages of surface-initiated ATRP (SI-ATRP) for the functionalization of electrospun materials.

Surface-initiated atom transfer radical polymerization (SI-ATRP) is successfully applied to electrospun constructs of poly(L-lactide). ATRP macroinitiators are adsorbed through polyelectrolyte complexation following the introduction of negative charges on the polyester surface through its blending with a six-armed carboxy-terminated oligolactide. SI-ATRP of glycerol monomethacrylate (GMMA) or 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA) allows then to grow surface films with controllable thickness, and in this way also to control the wetting and interactions of the construct.

Surface-initiated ATRP modification of tissue culture substrates: poly(glycerol monomethacrylate) as an antifouling surface.

Surface-initiated atom transfer radical polymerization (SI-ATRP) can be used to produce conformal coatings of controlled thickness on virtually any surface, providing to it specific physico-chemical and biological properties. Here we have tackled the problem of modulating cell adhesion on typical culture substrates; tissue culture polystyrene (TCPS) offers a number of favorable properties (optical transparency, chemical stability, sterilizability, availability in a wide variety of shapes) but somehow limited biological function. A fine tuning of cell adhesion can, on the contrary, allow better control cell phenotype during cell expansion or, by using responsive polymers, allow attachment/detachment cycles with reduced cell damage.

Polymers and Sulfur: what are Organic Polysulfides Good For? Preparative Strategies and Biological Applications.

Sulfur(II)-containing polymers (polysulfides) combine flexible synthetic and processing techniques with a unique responsiveness to oxidants. Here, the polysulfide oxidative sensitivity is put into the biological context of the development of new anti-inflammatory therapies - the development of new anti-inflammatory methodologies, adopted interactions and the minimisation of foreign-body reactions - through the review of 50 years of research on polysulfide synthetic methodologies. Attention is paid to the identification of the most flexible and robust preparative techniques.

Layer-by-layer deposition of polyelectrolyte macroinitiators for enhanced initiator density in surface-initiated ATRP.

The layer-by-layer (L-b-L) deposition of oppositely charged polyelectrolytic macroinitiators has been demonstrated on planar silica substrates. The build-up of the macroinitiator multilayers was monitored by ellipsometry (up to 21 layers) and dual polarization interferometry (up to 17 layers) and good agreement was found between these techniques. The increase in L-b-L thickness was approximately linear, with an average thickness of 2.

Characterization of layer-by-layer self-assembled multilayer films of diblock copolymer micelles.

The in situ layer-by-layer (LbL) self-assembly of low Tg diblock copolymer micelles onto a flat silica substrate is reported. The copolymers used here were a cationic poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2-(diethylamino)ethyl methacrylate) (50qPDMA-PDEA; 50q refers to a mean degree of quaternization of 50 mol % for the PDMA block) and zwitterionic poly(methacrylic acid)-block-poly(2-(diethylamino)ethyl methacrylate) (PMAA-PDEA), which has anionic character at pH 9. Alternate deposition of micelles formed by these two copolymers onto a silica substrate at pH 9 was examined.

Biomimetic deposition of silica templated by a cationic polyamine-containing microgel.

We report using poly(acrylamide-co-2-(dimethylamino)ethyl methacrylate, methyl chloride quaternized) cationic microgels as a porous colloidal template for biomimetic in situ silica mineralization, allowing the well-controlled synthesis of submicrometer-sized hybrid microgel--silica particles and porous silica particles by subsequent calcination. The microgels were prepared by inverse emulsion polymerization in the presence of a bisacrylamide cross-linker. Silica deposition was achieved by simply stirring an aqueous mixture of the microgel particles and tetramethyl orthosilicate (TMOS) at 20 degrees C for 30 min.

Surface ATRP of hydrophilic monomers from ultrafine aqueous silica sols using anionic polyelectrolytic macroinitiators.

A convenient two-step route was developed to prepare new anionic ATRP macroinitiators from near-monodisperse poly(2-hydroxyethyl methacrylate) precursors by partial esterification with 2-bromoisobutyryl bromide, followed by esterification of the remaining hydroxyl groups using excess 2-sulfobenzoic acid cyclic anhydride. These new macroinitiators can be electrostatically adsorbed onto ultrafine cationic Ludox CL silica sols; subsequent surface polymerization of various hydrophilic monomers in aqueous solution at room temperature afforded a range of polymer-grafted ultrafine silica sols. The resulting sterically stabilized particles were characterized by dynamic light scattering, transmission electron microscopy, aqueous electrophoresis, FTIR spectroscopy, and elemental microanalyses.