Hyperbranched polymers with both highly branched structures and numerous vinyl functional groups have been synthesized via reversible activation/deactivation controlled polymerization of multifunctional vinyl monomers. By controlling the competition between propagation and reversible termination using a deactivation enhanced method, the growth rate of polymer chains is decreased and the onset of gelation is prevented until the system has achieved much higher levels of conversion than has previously been reported for nonenhanced systems. Here, we demonstrate this strategy by synthesizing highly branched, irregular dendritic polymers with a multiplicity of reactive functionalities such as vinyl and halogen functional groups, and controlled chain structure via deactivation enhanced atom transfer radical polymerization (ATRP) of a commercially available multifunctional vinyl monomerdivinylbenzene (DVB) and ethylene glycol dimethacrylate (EGDMA).

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The efficiency of various silver-based antimicrobial fillers (elementary silver and silver substituted materials) in polyamide (PA) toward their silver ion (Ag+) release characteristics in an aqueous medium was investigated and discussed. Anode stripping voltammetry (ASV) was used for the quantitative estimation of Ag+ release from these composites. The biocidal (Ag+) release from the composites was found to be dependent on the time of soaking in water and the nature of the filler. The long-term Ag+ release capability of the elementary silver-based PA/Ag composite is promising compared with the commercial counterparts. The silver ion release potential of polyamide composites where the silver filling was performed by using supercritical carbon dioxide (scCO2) is also discussed. The composites release Ag+ at a concentration level capable of rendering antimicrobial efficacy and proved to be active against the microbes. A good agreement exists between the Ag+ release experiments and antimicrobial test results. The observed results on the influence of the nature of the filler and crystallinity on the biocidal release and the varying long-term release properties could be helpful in the design of industrially relevant biomaterials.

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New CO2-philic hydrocarbon molecules were synthesized by reversible addition fragmentation chain-transfer polymerization. These poly(vinyl alkylates) show the highest solubility in supercritical CO2 of any hydrocarbon reported to date. By utilizing the anchoring ability of the thiocarbonylthio end group, the dispersion polymerization of N-vinyl pyrrolidone was successfully achieved in scCO2 leading to high yields of well-defined spherical polymer particles.

Electrodeposition is a widely used materials-deposition technology with a number of unique features, in particular, the efficient use of starting materials, conformal, and directed coating. The properties of the solvent medium for electrodeposition are critical to the technique's applicability. Supercritical fluids are unique solvents which give a wide range of advantages for chemistry in general, and materials processing in particular. However, a widely applicable approach to electrodeposition from supercritical fluids has not yet been developed. We present here a method that allows electrodeposition of a range of metals from supercritical carbon dioxide, using acetonitrile as a co-solvent and supercritical difluoromethane. This method is based on a careful selection of reagent and supporting electrolyte. There are no obvious barriers preventing this method being applied to deposit a range of materials from many different supercritical fluids. We present the deposition of 3-nm diameter nanowires in mesoporous silica templates using this methodology.electrochemistry ͉ nanomaterials

Recently, controlled radical polymerization techniques have received considerable interest because of the ability to synthesize species exhibiting precise molecular architecture. 1 The (reversible addition fragmentation chain transfer) RAFT technique allows the formation of polymers with a very narrow molecular weight distribution from a wide range of monomers. 2,3 In addition, the resulting polymer is free from undesirable metal catalysts that are present following other controlled polymerization techniques (e.g., atom transfer radical polymerization). 4 Other authors have shown that RAFT-mediated polymerizations can occur in supercritical CO 2 , and product with low polydispersity (PDI), albeit low conversion, was generally observed. [5][6][7][8] Hydrophilic/CO 2 -philic stabilizers were synthesized by RAFT 9,10 and in one case used in the dispersion polymerization of poly-(hydroxyethyl methacrylate). 9 However, the RAFT-terminated stabilizer was not used to control the kinetics of the polymerization, and low PDIs were not observed. Our work takes a significant step further, yielding high conversion, high molecular weight polymer and living microparticles.Supercritical fluids have emerged as acceptable replacements for organic solvents. scCO 2 is nontoxic, nonflammable, and inert and has an easily accessible critical point (T c ) 31.0 °C, P c ) 7.38 MPa). 11 Since the first successful radical dispersion polymerization in scCO 2 by DeSimone and co-workers, 12 numerous authors have reported successful polymerizations of various vinyl monomers. [13][14][15][16][17] While careful control of the solvent density can lead to polymer particles with well-defined morphology, simultaneous control over the polymer molecular weight remains elusive.

A core/sheath distribution of cell‐adhesive and non‐cell‐adhesive surface coatings is produced in porous biodegradable poly(D,L‐lactic acid) discs using sequential plasma polymerization. The figure and cover show an X‐ray micro‐computed tomography image of a section of a 10 mm diameter, 4 mm thick scaffold where fibroblast cells (shown in red) have been encouraged by the surface chemistry to penetrate to the scaffold core.