Thermoresponsive Surface Prepared by Atom Transfer Radical Polymerization Directly from Poly(vinylidene fluoride) for Control of Cell Adhesion and Detachment

Thermoresponsive surface was prepared from commercial poly(vinylidene fluoride) (PVDF) films via surface-initiated atom transfer radical polymerization. The direct initiation of the secondary fluorinated site of PVDF facilitated grafting of the N-isopropylacrylamide (NIPAAm) monomer. The PVDF surfaces grafted with poly(N-isopropylacrylamide) [P(NIPAAm)] were characterized by X-ray photoelectron spectroscopy. Kinetics study revealed that the P(NIPAAm) chain growth from the PVDF surface was consistent with a controlled process. The temperature-dependent swelling behavior of the surfaces in aqueous solution was studied by atomic force microscope. At 37 degrees C [above the lower critical solution temperature (LCST, about 32 degrees C) of NIPAAm], the seeded cells adhered and spread on the NIPAAm grafted PVDF surface. Below the LCST, the cells detached from the P(NIPAAm)-grafted PVDF surface spontaneously. The thermoresponsive surfaces are potentially useful as stimuli-responsive adhesion modifiers in the biomedical fields. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 976-980, 2010