Abstract
Poly(tetrafluoroethylene) (PTFE) plates grafted with N-isopropylacrylamide (NIPAAm) were prepared by combined use of the plasma treatment and photografting. The surface compositions of the grafted PTFE plates were analyzed by ESCA and thermo-responsive properties were investigated by contact angle measurements and ellipsometry. Since the contact angle values of the grafted PTFE plates decreased with an increase in the grafted amount of NIPAAm, it is considered that the wettabilities of the grafted PTFE surfaces come from the hydrophilicity of the grafted polymer chains. At the temperatures above the LCST of PNIPAAm the wettabilities of the grafted PTFE plates were lowered due to the contraction of the grafted polymer chains through hydrophobic interaction. The grafted amount of NIPAAm increased most in a monomer aqueous solution, but the most pronounced thermo-sensitivity was observed in an acetone solution. The highest grafted amount of NIPAAm and thermo-sensitivity were obtained in the monomer solution with the composition of acetone : water = 80 : 20 wt%. Further, the grafted layers of PNIPAAm onto PTFE evaluated by ellipsometry became thick and even with an increase in the grafted amount.
