Synthesis Of Polyaniline-titania Nanotube Arrays Hybrid Composite Via Self-assembling Polymerization And Its Application In Supercapacitor

In recent years, supercapacitor has attracted widely attentions from researchers forits advantages, such as rapidly charge-discharge ability, long-term cyclic life, etc.Polyaniline (PANI) is one of the most popular materials for supercapacitor electrode,because the polymer owns reversible redox states, controllable morphology, and highcapacitance. However, the PANI based electrodes always suffer from poor long-termlife. In order to solve the problem, we present a facile method thatγ-aminopropyltriethoxysilane (APTES) was used to modification the anodized TiO2NTA to provide grown sites of PANI, then, PANI was self-assembing and graftpolymerized on the TiO2NTA with higher surface for redox reaction.Our work aims to give some new insights in the kind of PANI-inorganic materialcomposites and their fabrication, enhance their capacitance behaviors and cyclic ability.The mainly innovated results are listed as below:①Compared the cases of presence and absence of APTES, the morphology andmechanism of growth were quite different. When TiO2NTA was modified with APTES,PANI grew inside the nanotubes at first, then, PANI grew along the wall of nanotubes. Itcan be inferred that aniline molecules intended to get into the TiO2nanotubes, whenTiO2was modified by APTES, because the ending–NH2served as initiated site forpolymerization. On the contrary, the PANI nanowires randomly aggregated on the topsurface of PANI-TiO2NTA. The PANI coating on the top of TiO2NTA was multilayeraggregation with respect to that on the modified one.②The result also indicated the impact of APTES on electrochemical properties ofcomposites. The anchoring effect of APTES made PANI uniformly grow on the bothinside and outside surface of TiO2NTA, which leaded to larger surface area for redoxreaction and higher capacitance. The covalent band of APTES enhanced the stability ofPANI during repeative doping-undoping. Meanwhile, multilayer aggregated PANI onthe top of nanotubes wasn’t supported by TiO2NTA structure, resulting in poor stabilityfor PANI-TiO2NTA composite.③The assembling strategy which combined anodization and graft polymerizationis facile, cheap and in favor of industrial scale production. We have optimized thefabrication strategy of composite, and demonstrated the effects of reaction conditions,such as anodic system, the crystal form of TiO2, the concentration of reaction agents, the concentration ratio of aniline and APS and the concentration of HCl solution onelectrochemical behaviors.④Mix phase TiO2-APTES-PANI composite was obtained by heat-treatment andself-assembing graft polymerization method. The morphology, structure andelectrochemical behaviors were also studied.