Building a smart surface with converse temperature-dependent wettability based on poly(acrylamide-co-acrylonitrile).

A smart surface with converse temperature-dependent (CTD) wettability was fabricated from an upper critical solution temperature-type (UCST-type) poly(acrylamide-co-acrylonitrile) (P(AAm-co-AN)) copolymer. The obtained surface exhibits a remarkable and reversible hydrophobic-hydrophilic transition depending on temperature with a high response rate. The static water contact angle of the surface decreases from 103° ± 2° to 60° ± 1° as the temperature increases from 30 °C to 80 °C. Further, the wettability of the UCST-type surface shows a positive linear relationship between wettability and temperature. This study for the first time provides an UCST-type smart surface with wettability that decreases by over 35° as the temperature increases by only 20 °C.