Thermo-response of ion track pores in copolymer films of methacryloyl- l-alanine methyl ester and diethyleneglycol-bis-allylcarbonate

Abstract

Copolymer films (100 μm thick) were prepared by cast polymerization of methacryloyl- l-alanine methyl ester (MA- l-AlaOMe) and diethyleneglycol-bis-allylcarbonate (CR-39). The films swell in water at temperatures below 60°C. The degree of swelling increases with decreasing temperature down to 0°C. The swelling capacity of the films increases with increasing MA- l-AlaOMe content. The thermal response is reversible. Swelling and shrinkage have different time constants of ∼24 h for swelling and ∼10 min for shrinkage. The films were subject to an ion track etching process consisting of a heavy ion irradiation using gold ions of 11.4 MeV per nucleon specific energy followed by subsequent etching of the latent ion tracks in NaOH solution. The resulting porous membranes show a reversible change of the pore diameters of ∼12% between 0°C and 60°C for a copolymer with 70 vol% MA- l-AlaOMe.