International audienceWe herein report the synthesis of original vinylidene fluoride (VDF)-based amphiphilic block copolymers by RAFT/MADIX polymerization. The controlled polymerization of VDF could be successfully mediated by a xanthate chain transfer agent as evidenced by SEC, 19F NMR and MALDI-TOF MS analysis. Copolymers of VDF and perfluoro(methyl vinyl ether) (PMVE) of varying controlled chain lengths were also obtained. Finally, the direct synthesis of main-chain fluorinated amphiphilic block copolymers was performed from hydrophilic poly(N,N-dimethylacrylamide) macro-RAFT agents. It is expected that this finding will open interesting perspectives for the development of new class of polymeric surfactants for the stabilization of emulsions based on water and supercritical carbon dioxide media
An enhancement of poly(vinyl ester) solubility in supercritical carbon dioxide (sc-CO(2)) can be achieved by decreasing the strength of the polymer-polymer interactions. To demonstrate this, a library of statistical copolymers of vinyl acetate and vinyl trifluoroacetate was synthesized by RAFT/MADIX polymerization with varying compositions at a given number-average molecular weight. These copolymers exhibited unprecedentedly low cloud-point pressures in sc-CO(2) at 40 °C compared with previously reported poly(vinyl esters). Surface tension measurements combined with a computational approach evidenced the prominent role played by polymer-polymer interactions.
This Review provides comprehensive guidelines for the design of CO2-philic copolymers through an exhaustive and precise coverage of factors governing the solubility of different classes of polymers. Starting from computational calculations describing the interactions of CO2 with various functionalities, we describe the phase behavior in sc-CO2 of the main families of polymers reported in literature. The self-assembly of amphiphilic copolymers of controlled architecture in supercritical carbon dioxide and their use as stabilizers for water/carbon dioxide emulsions then are covered. The relationships between the structure of such materials and their behavior in solutions and at interfaces are systematically underlined throughout these sections.
Well-defined statistical copolymers of vinyl acetate and 1-(trifluoromethyl)vinyl acetate were synthesized by RAFT/MADIX polymerization. These copolymers exhibited enhanced solubilities in supercritical CO 2 compared to poly(vinyl acetate). A copolymer composition−solubility optimum was observed, which resulted from a subtle interplay between polymer−polymer interactions and entropy of mixing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.