The Fabrication And Wettable Investigation Of Thermal And Electrical Responsive Polymer Film

Stimuli-responsive surfaces can react to the external stimuli, and have been realized by various elegant methods, which play an important role in industrial applications including chemical sensors, microfluidic devices, and so on. And wettability is an important property of solid surfaces that governed by both chemical composition and surface topographic structure. Therefore it is attracted great interests on controling the wettability by adjusting the chemical composition or surface topographic structure with external stimuli.In this paper, we successfully fabricated various responsive wettable surface with thermal responsive polymer, for example: poly(N-isopropylacrylamide) and poly(N-isopropylmethacrylamide), and the electrical responsive polymer, for example: Poly(2-acrylamide-2-methylpropane sulfonic acid), which the responsive macro- and micro-wettability, and adhesion force were investigated in detail, respectively.1 The rough copper mesh film with special hierarchical micro- and nanostructures is fabricated by ammonia oxidation method, then it is modified with the poly(N-isopropylacrylamide) by atom transfer radical polymerization(ATRP), which is a novel thermal responsive polymer. A temperature controllable water permeation process was realized on it. This research will help us to understand not only the static wettability on the surface, but also, most important, the dynamic properties of the micro- and nanostructure enhanced responsive wettability.2 A roughness-enhanced two-grade thermal responsive wettable film consisted with the poly(N-isopropylmethacrylamide)-block-poly(N-isopropylacrylamide) (PNIPMAM-b-PNIPAm) was fabricated on the silicon substrate by ATRP. And detailed AFM investigation indicated that the adhesion forces on such surface were also incresing with the temperature, which showed a two-grade force rundle just like the CA change. And the suitable sized micro- and nanostructure on the substrate plays an important role in this effect. The excellent property of two grade responsive wettability on the surface is very useful in various important applications including controllable protein separation, microfluidic devices, medicine release, and so on.3 Using a templated method, a superhydrophobic polymer nanoacetabula surface was fabricated, which is composed of the mixture of poly(N-isopropylacrylamide) and polystyrene. And the high adhesion force on the film can be controlled by the temperature. The aligned superhydrophobic nanoacetabula film like gecko'claw can be greatly applicated in smart liquid transportion and micro-sample analysis systems.4 Poly(2-acrylamide-2-methylpropane sulfonic acid) which can exhibit an extent of volume change under external electric field was grafted on the silicon substrate. Using conducting AFM, the microscopic wettability and the adhesion force was investigated, and the results indicated they can be conveniently triggered by a negatively charged AFM tip. It may be applicated in the smart nanodevice, controlled microfluid device, data recording device, and so on.