A new strategy for solving hydrophobic membrane wetting: membrane structure design for membrane pore drying by spontaneous dehydration

The problem of hydrophobic membrane wetting acts as a bottleneck and limits its widespread application. In this paper, we point out from a new perspective that the key to solving the hydrophobic membrane wetting problem is how to realize the drying of membrane pores. Herein, we designed a novel composite hydrophobic membrane structure that can realize the spontaneous-dehydration and drying of hydrophobic membrane pores. The composite hydrophobic membrane was prepared using the non-solvent-induced phase separation (NIPS) method. This composite hydrophobic membrane utilizes the difference in adhesion of hydrophilic and hydrophobic materials to water, and spontaneously removes the residual water in the hydrophobic membrane's pores through the hydrophilic layer. When the hydrophilic layer has sufficient hydrophilicity and hygroscopicity, the water in the hydrophobic layer is “sucked away” by the hydrophilic layer under the combined action of the repulsion force of the hydrophobic membrane material and the suction force of the hydrophilic layer membrane material. Compared to the traditional method of drying membrane pores by heating to evaporate the residual water in the pores, the composite hydrophobic membrane prepared in this study can complete drying only based on the characteristics of the its materials itself without external force. It avoids the use of large-scale heating and drying equipment and has great potential for industrial applications.