Enhancing the Hydrophobicity and Surface Roughness of Synthesized PVDF Membrane Using Evaporation and Non-solvent-Induced Phase Separation

This study focuses on the synthesis of a PVDF membrane using DMAc as the solvent through a combination of evaporation-induced phase separation (EIPS) and non solvent-induced phase separation (NIPS) techniques. The experimental findings underscore the significant role of thermodynamic and kinetic parameters in the phase inversion process, influencing the surface and transport properties of the resulting membrane. By precisely controlling the combined processes of EIPS and NIPS, a customized membrane with specific characteristics such as a rough surface (roughness of up to 725.9 µm) and hydrophobicity (water contact angle up to 117°) was successfully achieved. The synthesized membrane exhibits good membrane properties (total porosity ≥ 50%, mean pore size ranging from 0.01 to 0.35 μm) with well-connected pores. To assess its quality, the membranes permeate flux, reaching up to 12.8 kgh⁻¹ m⁻², and salt rejection rate of 99.8% were evaluated using Vacuum Membrane Distillation (VMD). Furthermore, a fouling study was conducted to investigate the impact of operating time on membrane performance, revealing a negligible decline in membrane fouling over a 200-h run.