Variation of Immiscibility Gap in Polymer Solution Containing Alkane and Effects on Providing the Membrane

Document Type : Research Paper


Sustainable Membrane Technology Research Group (SMTRG), Faculty of Petroleum, Gas and Petrochemical Engineering (FPGPE), Persian Gulf University (PGU), P.O. Box 75169-13798, Bushehr, Iran


In oredr to reduce costs and save time for the membrane manufacturing process, it is necessary to improve the quality of membranes by modeling usage. In this study, Flory Huggins model was used to predict quaternary-system containing polyether sulfone, N-Methyl-2-pyrrolidone, water and used alkanes as an additive. Due to the solubility parameters and molar alkane volumes, the interaction parameters changed which influenced the membrane morphology. In the meantime, modeling showed that hexane had no effect on the immiscibility gap, and the decane had a greater effect compared to hexane. But the tetradecane, due to the increased interactions, could greatly increase the immiscibility gap and increase the thermodynamic instability. Hence, those instabilities can become subjected to faster membrane entelechy, construct a pores skin layer, and change the membrane morphology. Whatever the immiscibility gap rise, the proportion of pores in the skin layer will increase and vice versa.