Synthesis of electrically conductive polymer/inorganic composites: In situ oxidative polymerization/intercalation of conducting polymers in layered hosts.

摘要

The redox intercalation of polyaniline, polypyrrole and polythiophene in V{dollar}sb2{dollar}O{dollar}sb5{dollar} xerogel is a topotactic reaction which was achieved by reacting aniline, pyrrole and 2,2{dollar}spprime{dollar}-bithiophene with V{dollar}sb2{dollar}O{dollar}sb5{dollar} xerogel. Upon intercalation, the interlayer spacings expanded from 11.55A to 13.94A, 15.20A and 14.70A for polyaniline/V{dollar}sb2{dollar}O{dollar}sb5{dollar} polypyrrole/V{dollar}sb2{dollar}O{dollar}sb5{dollar} and polythiophene/V{dollar}sb2{dollar}O{dollar}sb5{dollar} respectively. These data are consistent with containing alternating monolayers of conducting polymers and V{dollar}sb2{dollar}O{dollar}sb5{dollar} xerogel. The room temperature conductivity of polymer/V{dollar}sb2{dollar}O{dollar}sb5{dollar} composites is in the range of 10{dollar}sp{lcub}-4{rcub} sim{dollar} 10{dollar}sp0 Omegasp{lcub}-1{rcub}{dollar}cm{dollar}sp{lcub}-1{rcub}{dollar} and decreases with decreasing temperature. The charge transport properties of these composites vary significantly from each other. They can be semiconductors or metal-like, with n-type or p-type conductivity depending on the reaction media, polymer/V{dollar}sb2{dollar}O{dollar}sb5{dollar} ratio and polymer molecular weight. Upon standing in air, the magnetic moment of all polymer/V{dollar}sb2{dollar}O{dollar}sb5{dollar} composites decreases. This is due to reoxidation of some of V{dollar}sp{lcub}4+{rcub}{dollar} centers to V{dollar}sp{lcub}5+{rcub}{dollar} by oxygen. Another effect oxygen has on (PANI){dollar}sb{lcub}rm x{rcub}{dollar}V{dollar}sb2{dollar}O{dollar}sb5{dollar}nH{dollar}sb2{dollar}O is to cause the intercalated polyaniline chains to oxidatively polymerize further to form longer chains. This increases the conductivity.; (PANI){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl was obtained by reacting FeOCl with excess aniline in acetonitrile at room temperature. The resulting products have interlayer spacing equal to 13.96A which is also consistent with containing alternating monolayers of FeOCl and polyaniline. X-ray and electron diffraction studies of single crystal (PANI){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl show a superlattice phenomenon suggesting a regular arrangement of polyaniline chains in FeOCl layers. The room temperature conductivity of (PANI){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl layers. The room temperature conductivity of (PANI){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl is around 10{dollar}sp{lcub}-3{rcub}{dollar} to 10{dollar}sp{lcub}-1{rcub} Omegasp{lcub}-1{rcub}{dollar}cm{dollar}sp{lcub}-1{rcub}{dollar} and the thermoelectric power of all samples shows p-type semiconductor behavior. Upon sitting in air (aging), two separate processes occurred: the FeOCl is hydrolyzed to {dollar}beta{dollar}-FeOOH, and polyaniline chains continue to oxidatively polymerize forming longer chains of polymer.; Intercalation of polyfuran was achieved by taking advantage of the lower oxidation potentials of terfuran and quaterfuran. Two different products were isolated depending on the reaction conditions. In refluxing MeOH or CH{dollar}sb3{dollar}CN, the resulting product r-(PFu){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl, is a topotactic intercalation. However, the products isolated from methanothermal synthesis, m-(PFu){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl{dollar}sb{lcub}rm y{rcub}{dollar}(OMe){dollar}sb{lcub}rm 1-y{rcub}{dollar} in which the Cl atoms in FeOCl were partially replaced by MeO groups. Although the physicochemical properties of both phases are similar, r-(PFu){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl has higher conductivity than m-(PFu){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl{dollar}sb{lcub}rm y{rcub}{dollar}(OMe){dollar}sb{lcub}rm 1-y{rcub}{dollar}. Variable temperature thermopower data of both products show typical p-type semiconductor behavior similar to (PANI){dollar}sb{lcub}rm x{rcub}{dollar}FeOCl.