Preparation And Application Of The Adhesion-controllable Surfaces Based On Electrodeposited π-Conjugated Polymer Film

The phenomena called interface adhesion, i.e., the liquid/solid substances or chemicals are sticked on the surfaces of materials used, is often observed. Sometimes such interface adhesion can be effectively applied to actual engineering. However, inconvenience even damage can be caused to our life and production in the most cases, for example, icing on electrical power lines etc. Therefore it is necessary to take into account to prevent, suppress or eliminate such inconvenience or damage.Many studies have indicated that the interface adhesion between substances and material surfaces has strong relationship with the micro/nanostructure, chemical composition of the material surfaces and adhered substances, as well as the medium. Recently, special attention was received on controlling such adhesion by using various materials and methods. Inspirited by self-cleaning and anti-adhesion surfaces of natural plants and animals, lots of artificial adhesion-controllable or anti-adhesion surfaces have been successfully prepared by combining hierarchically micro/nano rough structure and special surface energy materials. The potential applications of such surfaces range from self-cleaning coatings, anti-fouling/bio-fouling coatings, anti-icing coatings, drag reduction and microflow devices, to oil-water separation and biotechnology. Most recently, many multi-functional and smart adhesion surfaces have been intensively developed to meet various new requirements of special adhesion interfaces.It was however revealed in many studies, that the related fabrication processes of such surfaces are usually complicated, time-consuming, high-cost, and even unable to be coped easily by others. Furthermore, their practical applications are often limited by the poor thermal/mechanical stability of the as-prepared coatings. Especially, developing intelligent surfaces with controllable adhesion has been greatly hindered due to the factors such as the lack of alternative stimulus response materials, complex fabrication process, long period for wettability transition, harsh stimulus conditions and so on. Thus, it still remains a great challenge to fabricate a robust artificial biomimetic surface with multi-functional or adhesion-controllable properties.We hereby report a novel methodology for the preparation of the adhesion-controllable surfaces based on electrodeposited π-conjugated polymer film and their application in this dissertation. All π-conjugated polymer films were prepared by the electrochemical polymerization method. Several adhesion-controllable surfaces based on the electrodeposied π-conjugated polymer films, such as the electro-responsive adhesion-tunable surfaces, multifunctional self-cleaning surfaces and the surface with the tunable cell adhesion, were demonstrated in detail. It is worth to note that both the double-layered electrodeposition method and sacrificial electrodeposited-polymer-template strategy were proposed for the first time by us. The innovation of the dissertation and the main research contents include:1. The superhydrophobic S-PTHF film with controllable surface structure, tunable surface chemical composition was prepared by using the double-layered electrochemical deposition method proposed for the first time by our group. The as-prepared porous S-PTHF film could be doping and dedoped reversibly by controling the applied potential, leading to the adhesion switching of water-droplet on the film between pinned and rolling states, respectively. 2. The electric-responsive porous polythiophene film(PEDOT-P(3-MTH)) with reversible wettability transformation between superhydrophobicity and superhydrophilicity was successfully prepared by using the double-layered electrochemical deposition method mentioned above. The as-prepared film presents the super-hydrophobiciy with WCA > 150° in dedoping state and the superhydrophilicity with WCA ~ 0° in doping state. 3.A sacrificial electrodeposited-polymer-template strategy was developed for the in situ preparation of the transparent, thermally and mechanically stable superhydrophobic silica coating. This silica coating was prepared by using the highlyporous network-like PEDOT film electrodeposited indium-tin oxide(ITO) electrode as templates. After chemical vapour deposition(CVD) of tetraethoxysilane(TEOS) and annealing, the silica coating inherits a porous nanostructure from PEDOT film. After fluorination, it presents a superhydrophobic surface with a static water contact angle of 168.0° ± 1° and a low sliding angle(< 2°). The as-prepared silica coating has a higher transparency with even 92.8% transmittance at 661 nm than that of ITO glass. The silica coating could remain of its superhydrophobicity after subjected to the harsh environment tests, such as the high temperature of up to 400°C, the hydraulic pressure of up to 650 k Pa and even the sand abrasion. 4. The large-scale superhydrophobic polypyrene film with petal-like porous structure and strong excimer fluorescence was prepared by using electrochemical polymerization method. To protect the fragile structure of the polypyrene film and improve its water-impact resistance, we coated the film with a silica layer made via CVD of TEOS. After fluorination, the as-prepared FPSH film not only exhibited a superhydrophobic self-cleaning surface with a static water contact angle of 163° ± 1° and a sliding angle of 4° ± 1°, but also ideally inherited the excellent blue-green fluorescence of the polypyrene film. 5. The SSPTH film was prepared on an ITO glass electrode by using double-layer electrodeposition method, and the film presented electrochemically responsive water-droplet adhesion switching between high- and low-adhesion superhydrophobic states. This change in water-droplet adhesion results in a change in cell adsorption on the SSPTH film. Prevention of cell adhesion on the surface of low-adhesion(dedoped) SSPTH films can be observed, whereas high-adhesion(doped) SSPTH films can stick Hela cells.