HRP-mediated inverse emulsion polymerisation of acrylamide in supercritical carbon dioxide

Abstract

We report the horseradish peroxidase (HRP)-mediated inverse emulsion polymerisation of water-soluble acrylamide in supercritical carbon dioxide (scCO₂). The enzymatic polymerisation takes place within water droplets formed in scCO₂. These are either stabilised as reversed micelles using perfluoropolyether ammonium carboxylate (PFPE-COO⁻NH₄⁺) or in the absence of stabiliser using very high shear. The viability of water-in-CO₂ (W/C) emulsion as a reaction medium for in-situ enzyme-mediated polymerisation has been tested for the first time. There is significant interest in enzymes as they have proven to be powerful and environmentally friendly natural catalysts for the polymerisation of water-soluble monomers that can function under milder reaction conditions than those used in traditional free radical polymerisation techniques. Hence, the combination of scCO₂ and water as reaction medium is a significant advancement in natural polymerisation process.