, , , Richard A. Gross
The enzyme Candida antarctica Lipase B (CAL B), immobilized on a crosslinked poly(methyl methacrylate) (PMMA) support, catalyzes the ring-opening polymerization of ε-caprolactone to make biodegradable polyesters. Weak hydrophobic interactions of CAL B physisorbed on the PMMA surface can permit catalyst leaching, decreasing the concentration of remaining enzymes for polymerization and contaminating the polycaprolactone (PCL) product. Recycling of the solid-supported polymerization catalyst is necessary for commercialization; this requires a thorough understanding of catalyst activity, stability and surface interactions under varied reaction conditions. A quartz crystal microbalance (QCM) was used to monitor in situ adsorption of CAL B at the solid-support interface, while deconvoluting background events, such as polymer swelling or non-specific binding. A crosslinked PMMA thin film (50 nm) on a QCM crystal was fabricated to mimic the hydrophobic surface of the catalyst bead. The morphology of the enzyme immobilized surface is smoother than the unmodified PMMA, indicating enzyme adsorption occurs in the outer pores of the PMMA surface.
Surfaces & Interfaces
June 24-29, 2012
MACRO 2012: 44th Annual IUPAC World Polymer Congress
ring-opening polymerization, enzyme catalysis, green chemistry, surfaces and interfaces