Structure and thermal properties of porous polylactic acid membranes prepared via phase inversion induced by hot water droplets

Abstract In this study, water droplets generated using an ultrasonic atomizer at room temperature were replaced with water droplets heated to a high temperature (further denoted as hot water droplets) by an electrical heating steam generator during the preparation of porous membranes via phase inversion to reduce the amount of consumed water and fabrication time. As a result, porous polylactic acid (PLA) membranes were successfully prepared, and their microstructure and physical properties were studied by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Further, the effect of the PLA concentration on the morphology and thermal properties of the produced membranes was investigated. The application of hot water droplets significantly improved the exchange rate between the solvent and non-solvent phases, which increased the average pore diameter. Increasing the PLA concentration decreased the pore diameter, and the produced pores became irregular due to the decrease in the mobility of PLA molecules. At the same time, the higher PLA concentrations also increased the thermal stability and crystallinity of the porous membranes which were fabricated without using any toxic coagulants has and thus could be potentially used in tissue engineering and artificial organ development.