Synthesis And Properties Of Fluorinated PANI/SiO₂Organic-inorganic Hybrid Materials

In this paper, fluorinated PANI/SiO2hybrid films were prepared frompolyaniline emulsion solution and organosilane by a sol-gel route. The influence ofthe state of PANI emulision, different silane coupling agents and its amount, thenature of fluoro aniline monomer on the microstructure and properties of fluorinatedPANI/SiO2hybrid materials were investigated. The main study is divied into threeparts.Polyaniline emulsion was synthesized by semi-continuous emulsionpolymerization. The effect of systhesis process, the amount of emulsifier and water,and the nature of emulsifiers on morphology and properties of polyaniline wereinvestigated by SEM, FT-IR, UV-Vis and TG. The results indicated thatsemi-continuous emulsion polymerization was preferred to obtain, uniform PANIparticles with small size. In comparison with other emulsifiers, the stability ofpolyaniline emulsion using sodium dodecyl sulfate as the emulsifier was the best,which was due to the small size and homogeneous dispersion of PANI nanoparticles.It was also found that emulsifiers not only could effectively affect the size of PANInanoparticles, but also could prevent the aggregation of PANI nanoparticles.PANI/SiO2organic-inorganic hybrid films were prepared directly frompolyaniline emulsion solution and silane coupling agents by a sol-gel process. Theeffect of different silane coupling agents and its amount on morphology andcorrosion resistance ability of the PANI/SiO2hybrid materials were characterized bySEM, FI-IR, UV-Vis, TGA, potentiodynamic polarization analysis and contact angletesting. It was demonstrated that there was different interaction between thehydrolysate of silane coupling angents and PANI, which had a significantly influenceon the micro-structure and properties of the PANI/SiO2hybrids. When usingGPTMS as the precursor, the hybrid films had a homogeneous and smooth surfacewithout detectable cracks. Moreover, the thermal behavior and corrosion resistantability of the PANI/SiO2hybrids were also much better than others. It was also foundthat the increase of GPTMS content can improve the microstructure, thermal behavior and corrosion resistant ability of the PANI/SiO2hybrid films.Polyfluoroaniline-organosiloxane hybrid films were successfully preparedfrom polyfluoroaniline emulsions and GPTMS through a sol-gel method. Thepolyfluoroaniline emulsion was performed by a chemical method in acidic mediumusing3-fluoroaniline (F1ANI) and3,5-bis(trifluoromethyl)aniline (F6ANI) asmonomer, respectively. The influence of GPTMS/F1ANI molar ratios and the natureof fluoroaniline monmer on the morphology and properties of thepolyfluoroaniline-organosiloxane hybrid films was also discussed. It was found thatthe hybrid films are highly water repellent. In addition, increasing the GPTMScontent could significantly improve the microstructure, thermal behaviour andcorrosion resistant ability of the hybrid films, whereas the water repellency ofhybrids decreased slowly. Moreover, the nature of fluoroaniline monomer had asignificantly influence on the morphology and surface properties ofpolyfluoroaniline-organosiloxane hybrid films.