Superhydrophobic behavior of polyimide-siloxane mats produced by electrospinning

In this study, a series of novel superhydrophobic polyimide-siloxane electrospun mats was prepared using an electrospinning process. Segmented polyimide-siloxane copolymers were prepared using 4,4'-oxydianiline (ODA) and 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) as hard segments and aminopropyl terminated polydimethylsiloxane (APPS) and BTDA as soft segment. The polyimide-siloxane copolymers were synthesized by varying the APPS loading (10 and 20 mol%) and also the molecular weight of APPS (1000 and 2500 g/mol), respectively. Electrospinning of the polyamic acids was followed by thermal imidization to construct the electrospun polyimide-siloxane mats. The electrospun mats were characterized by FTIR, scanning electron microcopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimeter (DSC) and contact angle measurement. According to SEM results, the polyimide-siloxane electrospun mats have nano-roughness morphology. Bead on string type surface morphology that has been generated by electrospinning yields stable superhydrophobicity with a contact angle of 167 degrees.