The Controllable Synthesis Of Uniform Conducting Polymer Nano/Micro-structures

The conducting polymers, such as polyaniline(PANI) and polypyrrole(PPy), with well-defined morphology like nano/microstructures attract increasing attention because of their wide potential applications in sensors, actuators, biomedicines, device, separation membranes, supercapacitors, and etc. Thus, it is important to fabricate nanostructured conducting polymers with controllable morphology and sizes. In this work, well-defined PANI and PPy nanostructure are controllably synthesized by chemical oxidative polymerization. Additionally, the influence of reaction conditions on the morphologies of the PPy has been systematically investigated. A possible formation and growth mechanism of PANI and PPy nanostructures is also offered here:(1) Aniline was oxidative polymerized in the presence of cadmium acetate. As the result, superhydrophobic hollow polyaniline (PANI) bars were prepared, which were also composed of substructure, nanorod-arrays. Toward preparing these PANI bars, self-assembling and "template" methods were simultaneously applied. The self-removing water-soluble "template" was probably formed when a high concentration of aniline (0.5 M) was added into the cadmium acetate solution, and then decomposed gradually during the oxidative polymerization of aniline. The influence of reaction conditions such as the molar ratios of Cd(Ac)2 to aniline, the concentration of aniline, polymerization temperature, etc, on the morphologies of the PANI has been systematically investigated, The formation mechanism of the hollow PANI bars was discussed.(2) High crystalline uniform polypyrrole(PPy) sheets have been synthesized by chemical oxidative polymerization of pyrrole(Py) at about 15℃, using ammonium persulfate((NH4)2S2Os, APS) as oxidant, cetyltrimethylammonium bromide (CTAB)-sodium lauryl sulfate(SDS) micelle as the co-templates. The influence of the concentration of CTAB, SDS on the morphologies of the PPy has been systematically investigated. The result shows that high crystalline uniform PPy sheets can be obtained at 0.01 M,0.01 M,0.03 M, respectively. A plausible mechanism of formation of the high crystalline PPy sheets is proposed.(3) Two kinds of nanostructures, nanowires and nanoribbons were prepared with polypyrrole (PPy) by controlling the concentration of acrylic acid (AA) in systems containing cationic surfactant, cetyltrimethylammonium bromide (CTAB) at about 12℃. The effect of reaction conditions involving the concentration of AA, CTAB, pyrrole as well as the reaction temperature was systematically studied on the final structures of prepared PPy. The results revealed that the polymerizing AA, resulting in PAA, played a key role in controlling the change of PPy nanostructures. A possible mechanism was also briefly discussed on the formation of these two nanostructures (nanowires and nanoribbons).(4)Multilevel structure polyaniline which are of one-dimensional(1D) micronfibers or microsheets have been synthesized by chemical oxidative polymerization using AA as dopant and FeCl3 as oxidant at about 65℃. The effect of reaction conditions involving the concentration of AA, aniline, as well as the reaction temperature etc was systematically studied on the final structures of prepared PANI. A plausible mechanism of formation of the Multilevel structure polyaniline is proposed.