A novel class of surface-active carbohydrate esters is prepared by a two-step strategy that takes advantage of the selectivity of enzymatic catalysis and the versatility of the thiol-Michael addition reaction. The surfactant performance of the produced aliphatic, fluorinated and silicon based sugar esters are evaluated by surfacetension measurements. The novel thiolated mannose, made available in
amphiphilic carbohydrate esters, respectively. A surface activity study showed that these new compounds possess valuable properties and display specific behavior at the air-waterinterface. It also demonstrated the greater flexibility of the thioether moiety in the spacer of the surfactants produced via a thiol-ene reaction in comparison with the triazole heterocyclic rings in similar glucose-based surfactants
Synthesis of microsphere-loaded porous polymers by combining emulsion and dispersion polymerisations in supercritical carbon dioxide
作者:Cédric Boyère、Alexandre F. Léonard、Bruno Grignard、Audrey Favrelle、Jean-Paul Pirard、Michel Paquot、Christine Jérôme、Antoine Debuigne
DOI:10.1039/c2cc33978a
日期:——
Highly porous materials were produced by acrylamide polymerisation templated by supercritical CO2-in-water emulsions using new fluorinated glycosurfactants. Properties of the resulting polymer scaffolds were tuned by performing dispersion polymerisations within their cavities filled with supercritical CO2.
Macroporous poly(ionic liquid) and poly(acrylamide) monoliths from CO2-in-water emulsion templates stabilized by sugar-based surfactants
作者:Cédric Boyère、Audrey Favrelle、Alexandre F. Léonard、Frank Boury、Christine Jérôme、Antoine Debuigne
DOI:10.1039/c3ta11073g
日期:——
Highly interconnected poly(acrylamide) (PAM) and poly(vinylimidazolium) (PVIm) porous monoliths were templated by carbon dioxide-in-water (CO2/W) high internal phase emulsions (HIPEs), a toxic-solvent free process. A range of sugar-based fluorinated surfactants prepared by chemoenzymatic synthesis were used as emulsifiers. Both the concentration and the structure of the surfactants, especially the length of their CO2-philic part and of their spacer between the sugar head and the tail, were found to strongly affect the cellular structure and morphology of the PAM polyHIPEs, i.e. the size of pores and cells. A mannose derivative bearing a chain ranging from 6 to 10 perfluorinated carbons and a long spacer emerged as the best stabilizer, leading to a porous monolith with average pores and cell sizes (about 2.6 μm and 5–10 μm, respectively) among the lowest reported for polyHIPEs produced from CO2/W emulsions. The same template then served for the preparation of the first macroporous poly(ionic liquid) (PIL) polyHIPE by using 1-vinyl-3-ethylimidazolium bromide as the monomer. Shrinkage of the final material was prevented by adjusting the divinylimidazolium crosslinker content. The resulting low density polyHIPE exhibits small spherical cells (∼5 μm) connected by numerous small pores (∼2 μm), confirming that the CO2/W HIPE templating methodology based on fluorinated glycosurfactants is a technique of choice for the preparation of macroporous PILs.