Control of Water Permeability by Mechanochemically Expanding and Contracting Membranes and Its Application to Controlled Substrate Release in Enzyme Reaction

Abstract

Effect of mechanochemical contraction of a crosslinked poly(methacrylic acid) (PMAA)membrane on the water permeability was studied by forming complexes with poly (ethylene glycol) (PEG), poly(Nvinylpyrrolidone) (PVP), poly(methyl vinyl ether) (PMVE) and poly(vinyl alcohol) (PVA). It was found that PEG and its derivatives increase water permeability of the membrane, however, PVP and PMVE rather prevented the water permation. From the experimental results of the membrane contraction as well as water permeability, it was assumed that a penetration of the polymer through the micropores of the membrane plays an essential role for the increased water permeation, and that the polymer is required to have certain structure so as to make the successful penetration. This expanding and shrinking behaviors of the micropores of PMAA membrane was applied to control the diffusional velocity of substrate (saccharose) in order to control the enzyme (invertase) reaction. It was also found that the apparent release rate of raffinose entrapped in the crosslinked PMAA gel is also changed by the mechanochemical reaction of the gel.