Structure-Property Relationships in CO2-philic (Co)polymers: Phase Behavior, Self-Assembly, and Stabilization of Water/CO2 Emulsions.

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.

Enhancement of poly(vinyl ester) solubility in supercritical CO2 by partial fluorination: the key role of polymer-polymer interactions.

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.

Toward a full characterization of native starch: separation and detection by size-exclusion chromatography.

The structure of starch molecules is relevant to nutrition and industrial applications. Size-exclusion chromatography (SEC, also known as GPC) of native starch generally suffers non-satisfactory repeatability and reproducibility of the dissolution and separation. This work combines two polar organic solvents: dimethylsulfoxide for complete dissolution and dimethylacetamide to limit shear degradation. The separation is as repeatable as that of polystyrene standards performing dissolution and separation at 80 degrees C. Successful covalent-labeling on the glucose unit is claimed to be published here for the first time in non-degradative conditions and allows the use of UV detector with significantly higher sensitivity than with a refractometer.

Direct Synthesis of Vinylidene Fluoride-Based Amphiphilic Diblock Copolymers by RAFT/MADIX Polymerization.

We 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 size exclusion chromatography (SEC), 19F NMR, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (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.