Effect of temperature on the morphology of poly (lactic acid) porous membrane prepared via phase inversion induced by water droplets.

Temperature is a critical parameter that can control the morphology of poly (lactic acid) (PLA) porous membranes prepared through phase inversion induced by water droplets. It determines the volatilization rate of the solvent and the exchange rate between the solvent and nonsolvent. In this work, in order to investigate the effect of temperature on the morphology, PLA porous membranes were prepared via phase inversion induced by water droplets at different temperatures. The morphologies of the prepared membranes were observed using scanning electron microscopy, and the volatilization rate of the solvent and the exchange rate between the solvent and nonsolvent were tested separately. The experimental data indicated that the volatilization rate of the solvent was faster than the exchange rate between the solvent and nonsolvent. A uniform porous structure was obtained for the PLA membrane, and the pore size decreased with the increase in temperature from 25 °C to 75 °C. This result indicated that a PLA porous membrane with desired pore size could be achieved by adjusting the ambient temperature. • It benefits to control accurate the phase inversion behaviors. • A simple method was developed for precise control of the pore structure of the porous membrane. • Quantitative study of the phase change process reveals the pore formation mechanism. [ABSTRACT FROM AUTHOR]