Libing He

Electroactive polymer with oligoanilines in the main chain and azo chromophores in the side chain: synthesis, characterization and dielectric properties

By an oxidative coupling polymerization approach, we have synthesized a novel electroactive polymer with good solubility containing alternating phenyl-capped aniline tetramer in the main chain and azo chromophores in the side chain. Dielectric properties of the as-synthesized polymer were investigated in detail and gratifying results have been observed. Firstly, a large enhancement in the dielectric constant was achieved utilizing the method of doping the conjugated oligoaniline segments with hydrochloric acid. Secondly, the adjustment of dielectric constant was implemented primarily by means of exposing the samples to UV and visible irradiation, mainly owing to the photoisomerization derived from azo chromophores in the side chain. The detailed characteristics of the as-synthesized polymer were systematically studied by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). UV-vis spectra were used to monitor the photoisomerization and doping process of the polymer. The thermal characteristics of the polyamide were evaluated by thermogravimetric analysis (TGA). Moreover, the electrochemical activity of the polymer was explored by cyclic voltammogram (CV) measurement, showing that the intrinsic electroactivity of the oligoaniline was maintained in the polymer.

Synthesis and properties of novel electroactive poly(aryl ether ketone) bearing oligoaniline segments

A novel hyperbranched electroactive azo copolymer with different oligoaniline segments was synthesized by an oxidative coupling polymerization approach, exhibiting an exciting molecular structure. The detailed characteristics of the obtained copolymer were systematically studied by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC) and X-ray powder diffraction (XRD). The thermal resistance of the copolymer was investigated by thermogravimetric analysis (TGA). Through cyclic voltammogram (CV), we explored the electrochemical behavior of the copolymer. Moreover, photoisomerization process and doping process of the copolymer were monitored with UV–vis spectra. Dielectric properties of the as-synthesized copolymer were investigated in detail, and gratifying results have been reported. Firstly, a large enhancement in the dielectric constant was achieved utilizing HCl-doping of the conjugated oligoaniline segments. Secondly, the copolymer in HCl-doped form possessed much higher dielectric constants compared with the similar linear polymer, mainly due to the branched molecular architecture.

Novel electroactive aromatic polyamide with oligoanilines and azo groups in the backbone: synthesis, characterization and dielectric properties

A novel electroactive polyamide with alternating amino-capped aniline pentamer and azo groups in the main chain was synthesized via a four-step synthetic procedure. The characteristics of the obtained polyamide were studied in detail by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The thermogravimetric analysis (TGA) was used to evaluate its thermal characteristics, and the result showed the as-synthesized polymer had a good thermal stability. Besides, the electrochemical behavior of the polyamide was checked by cyclic voltammetry (CV) and the mechanism of electrochemical oxidation process was well studied. Furthermore, UV–vis spectra were used to monitor the doping process and photoisomerization process of the polyamide. Ratifying results were obtained in the investigation on dielectric properties of the as-synthesized polymer. The dielectric constant was greatly increased by treating the conjugated oligoaniline segments with hydrochloric acid.

Synthesis and properties of a novel multifunctional hyperbranched polyamide

A novel hyperbranched polyamide containing azobenzene and oligoaniline groups (HPA-AO) has been synthesized by A2+BB’2 strategy. The structures of the obtained HPA-AO were confirmed via nuclear magnetic resonance (NMR) and Fourier-transform infrared spectra (FTIR); morphological data was ascertained via X-ray diffraction (XRD). The HPA-AO exhibited good thermodynamic stability. Due to the introduction of oligoaniline segments, the HPA-AO material was endowed with reversible electroactivity, and adjustable dielectric properties. Furthermore, the optical properties of HPA-AO were studied in detail and the results indicated that this azobenzene-containing polymer possessed expected photoisomerization, photoinduced birefringence and patterning properties.