Photophysical characteristics of polyaniline with photochromic azobenzene side groups
Huang Kuna, Wan Mei-Xianga, Feng Weib
a Centre for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China; b Department of Polymer Materials Science and Engineering, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
Abstract Photochromic characteristics and optical molecular reorientation in conducting polymer such as polyaniline derivatives containing photochromic azobenzene moieties (PAPNPAPOA) in side chain are studied. Changes in the UV—vis absorption, refractive index, thickness, contact angle and morphology of these films after irradiation of a linearly polarized light with a wavelength of 365nm are measured. The trans-cis isomerization of PAPNPAPOA is proved irreversible even after withdrawing the UV light for a long time. That the structure of main-chain attends by the trans-cis isomerization of side-chain is confirmed by the absorption and the solution colour during the UV irradiation. These effects are discussed by taking the trans-cis isomerization of azobenzene into consideration.