Synthesis and photophysical properties of a poly(methyl methacrylate) polymer with carbazolyl side groups

Journal of the Brazilian Chemical Society

Martins, Tatiana D.¹  Universidade Estadual de Campinas, Campinas, Brazil¹  Georgetown University, Washington, USA¹  Atvars, Teresa D. Z.¹  Weiss, Richard G.¹ 

关键词: carbazole;    carbaxolyl-based poly(methyl methacrylate);    luminescence;    temperature dependence;    relaxation processes;   

DOI  :  10.1590/S0103-50532008000800003

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

The photophysical properties of solutions and films of poly(methyl methacrylate) (PMMA) containing 1.6 mol % of randomly distributed pendant ethyl carbazolyl groups have been studied under steady-state and time-resolved conditions. The polymer was prepared by esterification of poly(methyl methacrylate-co-methacrylic acid) by 9H-carbazole-9-ethanol. At room temperature, the steady-state fluorescence spectrum is attributed to isolated lumophores in solution, but is much more complex in films where emission is detected from isolated groups, ground-state dimers and excimers. At 77 K, emission from both solutions and films contains a component of phosphorescence whose wavelengths overlap fluorescence from excited ground-state dimers and excimers. From the temperature dependence of the steady-state emission spectra of the films, recorded from 30 to 410 K, several types of relaxation processes are identified at temperatures similar to those of unmodified PMMA. Data by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and fluorescence spectroscopy are compared. They include the γ-relaxations from motions of small segments of the chains at 120-130 K (by fluorescence spectroscopy), the β-relaxation from motions of lateral ester groups (by DMTA and fluorescence spectroscopy) at 310 K and α-relaxations (glass transition onset) at 380 K (by DSC and DMTA).

【 授权许可】

Unknown