Preparation, Structure, and Properties of Track-Etched Membranes Based on Polylactic Acid

New applications, in particular in medicine, require the creation of track-etched membranes (TMs) with fundamentally new properties. There are well-known TMs made from polycarbonate, polyimide, polypropylene, polyethylene terephthalate, polyethylene naphthalate, and polyvinylidene fluoride; that is, polymers characterized by high chemical resistance. This study focuses on the development of a membrane made of the biodegradable polymer polylactic acid (PLA). Films prepared from a 1% solution of polylactic acid with a molecular weight of Mw = 121000 g/mol were taken as the initial matrix for TM fabrication. The films were irradiated with 1.2-MeV Xe ions at a fluence of 3.1 × 107 cm−2 on an IC-100 cyclotron. Etching was carried out in NaOH solutions of various concentrations (0.1, 1, or 2 mol/L) with varying the temperature from 18 to 70°С and the treatment time from 5 to 30 min. It has been revealed that the optimal treatment conditions for irradiated PLA films are etching in 1 M NaOH at a temperature of 44°C. This mode, with a time variation from 10 to 30 min, makes it possible to obtain through pores with a diameter of 0.6 to 1.5 µm with channel geometry close to cylindrical. It has been found that an increase in the etching time over 20 min leads to a decrease in the roughness of both membrane sides.