Poly (ε‐caprolactone)‐based porous membranes for filtration applications—effect of solvents on precipitation kinetics, performance, and morphology

Abstract

AbstractThis work presents fabrication, precipitation kinetics, morphological analysis, and permeation performance of poly (ε‐caprolactone) (PCL) phase inversion membrane, which is a biodegradable polymer. Asymmetric membranes of PCL were fabricated by nonsolvent‐induced phase inversion method using different casting solvents. The effect of casting solvents on the precipitation kinetics, membrane morphology, and performance for filtration applications was studied. Solvents selected based on Hansen solubility parameter value were N,N‐dimethyl formamide, N‐methyl‐2‐pyrrolidone, tetrahydrofuran, triethyl phosphate, 1,4‐dioxane, and acetone. Ternary phase diagram constructed by cloud point measurement described the precipitation kinetics and thermodynamics of the phase inversion. The fabricated membranes were characterized by its thermal, mechanical, and morphology studies. Permeation performance of the prepared membranes was analyzed by studying its equilibrium water content, porosity, and pure water flux. Morphology analysis of membranes showed porous asymmetric structure and spongy to finger like morphology in different solvents. Cloud point measurement showed different precipitation kinetics in each solvent leading to different morphological features to the polymer membranes. Size of the pores of all these membranes determined using the Guerout–Elford–Ferry equation suggests application of these membranes for microfiltration process.