Tailoring ordered microporous structure of cellulose-based membranes through molecular hydrophobicity design

Abstract

Ordered porous polymer membranes can be facilely prepared by breath figures. Previous studies have confirmed that the solidifying of polymer is crucial for the formation of ordered porous structures, which directly depends on the hydrophobicity of polymer. However, it is still unknown how strong hydrophobicity is required. Here, cellulose acetate derivatives (CADs) were used to investigate the effect of hydrophobicity on ordered porous structures. The CADs with different hydrophobicity were firstly synthesized via simple reactions, and then the porous membranes were fabricated by the breath figure method. It was found that the pore size showed a decreasing trend with hydrophobicity, and the degree of order of porous structures firstly increased and then dropped, showing a critical hydrophobicity value for the transition of the degree of order. Therefore, it was confirmed that suitable hydrophobicity is critical for ordered porous structures of CADs while excessive hydrophobicity may impair the ordered structures.