One Proposal for Increase in the Grafted Amount of PNIPAAm onto PTFE Plate by Combination Use of Plasma-treatment and Photografting

Abstract

Poly(tetrafluoroethylene) (PTFE) plates grafted with N-isopropylacrylamide (NIPAAm) as a hydrophilic monomer have been prepared by the combined use of the plasma treatment and photografting. The surface compositions of the grafted PTFE plates were analyzed by ESCA and the thermo-responsive properties followed by contact angle measurements. To obtain a high grafted amount of PNIPAAm, we cured oxygen-plasma-treated PTFE plates in oxygen atmosphere or after being dipped in acetone and methanol. Alternatively, we prepared the PTFE plates through the method of discontinuous and continuous irradiation of oxygen-plasma treatment. Then, the plasma treated PTFE plates were photografted in an aqueous 1.5 mol/dm3 NIPAAm solution. The ESCA spectra revealed introduction of groups containing oxygen and NIPAAm onto PTFE plates. The grafted amount of PNIPAAm onto PTFE increased over continuous oxygen plasma irradiation. Further, the grafted amount of PNIPAAm was proportionally effective to the thermosensitivities of the PTFE-g-PNIPAAm plate.