The role of conductivity and molecular mobility on the photoanisotropic response of a new azo-polymer containing sulfonic groups

• Main Authors: Alauddin, S.M (Author), Aripin, N.F.K (Author), Chaganava, I. (Author), Martinez-Felipe, A. (Author), Velayutham, T.S (Author)
• Format: Article
• Language: English
• Published: Elsevier B.V., 2020
• Subjects: Azo-Polymers; Conductivity; Dielectric spectroscopy; Photoanisotropy; Trans-to-cis photoisomerisation; UV-Vis spectrophotometry
• Online Access: View Fulltext in Publisher; View in Scopus

 We report the preparation of a new light-responsive side-chain terpolymer containing azobenzenes, as chromophoric components, sulfonic groups, as polar components, and methacrylate groups, as film forming components, and we provide a detailed characterisation of its thermal parameters, photoanisotropic character, dielectric response and optoelectronic properties. The poly[(4-methoxyazobenzene -4′-oxy) methacrylate]-co-poly[2-acrylamido-2-methyl-1-propanesulfonic acid]-co-poly[methyl methacrylate], MeOAzB/AMPS/MMA, was prepared by radical copolymerisation, possesses high thermal stability and is amorphous. Its high glass transition (Tg = 151 °C) is explained by steric effects (induced by the bulky azobenzenes) and hydrogen bonding (promoted by the polar sulfonic groups) near the polymeric backbone, which may also reduce the photoanisotropic efficiency. The transition between the energy levels of the azobenzenes (MeOAzB) in the terpolymer is controlled by p-type conductivity, and can be associated to motions in the side-chains containing the sulfonic groups (AMPS), which are locally activated below the MeOAzB/AMPS/MMA glass transition. © 2019 Elsevier B.V.