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

Abstract

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.

Enhancing oil–water emulsion separation using improved styrene–acrylonitrile copolymer membrane: Experimental and thermodynamic study of the impact of solvent mixtures

“…As can be seen from Figure 5, the SAN30 membrane made of pure solvent is fragile and has low mechanical resistance. In the case of single solvent, as observed in the research of Hamta et al 13,23 the presence of macropores in the cross-section of the membrane has reduced the mechanical resistance. The membrane fabricated from the ratio of 50%-50% solvents has more mechanical resistance than the pure solvents, and it is expected that this membrane has fewer large pores in its cross-section than the pure solvents.…”

“…The observed trend indicating a direct relationship between solvent ratio, water contact angle, and hydrophilicity. The increased hydrophilicity can be attributed to the specific characteristics of the solvents and their interactions with the styrene co‐acrylonitrile polymer, influencing the surface properties 14,23 …”

“…The increased hydrophilicity can be attributed to the specific characteristics of the solvents and their interactions with the styrene co-acrylonitrile polymer, influencing the surface properties. 14,23 4.3 | Membrane performance SAN30 membrane's performance was evaluated under varying feed conditions-pure water and a stable oil-water emulsion (500 mg/L, with Tween80 as a surfactant). Figures 8 and 9 depict the flux of pure water and oil-water emulsion, respectively, through different SAN30 membranes.…”