Preparation of wettability modulated thermoresponsive surfaces by ATRP and elution control of biomolecules

Temperature-dependent aqueous wettability of poly(N-isopropylacrylamide) (PIPAAm)-grafted surfaces was regulated by thickness of graft polymer layer and architecture of polymer chains utilizing surface-initiated atom transfer radical polymerization (ATRP). Hydrophilic property on the PIPAAm-grafted surfaces depends on polymer layer thickness at low temperature range. More hydrophobic surface properties were observed for poly (n-butyl methacrylate) (PBMA)-b-PIPAAm-grafted surfaces above PIPAAm's transition temperature. Applying surface-initiated ATRP of IPAAm to inner surfaces of microcapillaries, the retention times of steroids were controlled solely by temperature changes. Testosterone showed stronger interaction with more hydrophobic PBMA-e-PIPAAm-grafted surfaces above PIPAAm's LCST, and baseline separation of steroids was successfully achieved within 10min by only temperature alterations.