Effect of ether on the kinetics of formation in membrane formation via phase inversion process

The effect of ether (EE) on the kinetics of membrane formation is investigated in polyethersulfone with cardo/EE/N, N dimethylacetamide casting solution. The results show that the membrane formation kinetics is different from the commonly accepted conclusion that a single linear correlation between square of precipitation front move (L²) and gelation time (t) existed for the whole gelation process. Four different linear correlations between the value of L² and gelation time t, are identified. Compared with the morphology of evolution of the membrane, these four correlations correspond to four consecutive gelation steps. The addition of EE could work in favor of the enhancement in the demixing of casting solution thermodynamically. The increase of EE concentration lead to the increase of casting solution viscosity, and the gelation rate slow down. The introduction of EE has its hindrance effect on the cast solution viscosity exceeding the effect of thermodynamic enhancement in.