Mesomorphic and luminescent properties of side chain nematic liquid-crystalline polymers containing Ir(III). Issue 3 (19th February 2018)

• Record Type: Journal Article
• Authors: Song, Le-Ping; Cong, Yue-Hua; Zhang, Bao-Yan; Yao, Bing
• Is Part Of: Liquid crystals. Volume 45:Issue 3(2018)
• Page Start: 401
• Page End: 409
• Publication Date: 2018-02-19
• Subjects: Graft copolymers -- luminescence -- liquid-crystalline polymers (LCP) -- thermal properties; Liquid crystals -- Periodicals; 548.905
• DOI: 10.1080/02678292.2017.1336799
• Languages: English
• ISSNs: 0267-8292

Abstract

ABSTRACT: Iridium-containing liquid-crystalline polymers were obtained by graft copolymerisation using poly(methylhydrogeno)siloxane, 1-methyl-4-(4-(4-vinylcyclohexyl)cyclohexyl)benzene (M1 ) and an iridium complexes monomer (Ir-M2 ). The series of polymers contained different molecular fractions of Ir-M2 from 0% to 1.2%. All of these polymers showed mesomorphic behaviours. The introduction of small amount of iridium ions endowed liquid-crystalline polymers with luminescent properties. The chemical structures were characterised by IR and 1 H NMR. The mesomorphic properties and phase behaviour were investigated by differential scanning calorimetry, thermal gravimetric analysis, polarising optical microscopy and X-ray diffraction. With an increase of iridium complexes units in the polymers, the glass transition temperature ( T g ) did not change significantly; the isotropic temperature ( T i ) decreased. All polymers showed typical nematic marble textures, which was confirmed by X-ray diffraction. The temperatures at which 5% weight loss occurred ( T d ) were greater than 300°C for the polymers. The introduction of iridium complexes units did not change the liquid-crystalline state of polymer systems. With Ir 3+ ion contents ranging between 0.6 and 2.4 mol%, luminescent intensity of polymers gradually increased. GRAPHICAL ABSTRACT: