Thermally tunable surface wettability of electrospun fiber mats: polystyrene/poly(N-isopropylacrylamide) blended versus crosslinked poly[(N-isopropylacrylamide)-co-(methacrylic acid)].

This work reports on thermally tunable surface wettability of electrospun fiber mats of: polystyrene (PS)/poly(N-isopropylacrylamide) (PNIPA) blended (bl-PS/PNIPA) and crosslinked poly[(N-isopropylacrylamide)-co-[methacrylic acid)] (PNIPAMAA) (xl-NIPAMAA). Both the bl-PS/PNIPA and xl-PNIPAMAA fiber mats demonstrate reversibly switchable surface wettability, with the bl-PS/PNIPA fiber mats approaching superhydrophobic ≥150° and superhydrophilic contact angle (CA) values at extreme temperatures. Weight loss studies carried out at 10 °C indicate that the crosslinked PNIPAMAA fiber mats had better structural integrity than the bl-PS/PNIPA fiber mats. PNIPA surface chemistry and the Cassie-Baxter model were used to explain the mechanism behind the observed extreme wettability.