Fabrication Mechanism of Asymmetric Block Copolymer Membrane: Combination of Self-Assembly and Phase Separation Process

In this paper, the concept of functional mechanism of copolymer membrane formation is explained and analyzed from theoretical and experimental point of view. To understand the phase inversion process and control the final membrane morphology, styrene-acrylonitrile copolymer (SAN) membrane morphology through the self-assembly phenomena is investigated. Since the analysis of the membrane morphology requires the study of both thermodynamic and kinetic parameters, the effect of different membrane formation conditions is investigated experimentally; In order to perceive the formation mechanism of the extraordinary structure membrane, a thermodynamic hypothesis is also developed based on the hydrophilic coil migration to the membrane surface. This hypothesis is analyzed according to Hansen Solubility Parameters and proved using EDX, SAXS and contact angle analysis of SAN25. Moreover, the SAN30 membrane is fabricated under different operating conditions to evaluate the possibility of morphological prediction based on the developed hypothesis.