Fluid simulation of different solvents and additives for the preparation of PVDF blended membranes by NIPS method

Membrane separation technology is one of the most widely studied methods for wastewater treatment. This paper is based on the non-solvent-induced phase separation (NIPS) method, which is combined with phase-field simulation to develop a fluid model for the volume fraction of tetrameric polyvinylidene fluoride (PVDF).In this paper, DMSO, DMAc and DMF are used as solvents, and pure water is used as a gel bath to simulate the relevant parameters of PVDF membrane; and PVP and LiCl are used as additives, and DMF and DMAc are used as solvents for the two-by-two combinations, and by calculating the relevant parameters of the PVDF quaternary membrane system, comparing and verifying the simulation results through experiments. results show that: the different solvents on the PVDF membrane in the order of DMSO > DMAc > DMF; additive LiCl system, the polymer diffusion rate in the polymer solution layer are faster than the PVP system. However, the top layer of the polymer solution layer in the PVP system is relatively flat, while the top layer of the polymer solution layer in the additive LiCl system is more undulating or even broken, indicating that LiCl has a greater influence on the membrane than PVP.