Abstract
The influence of the organic ionic salt crystal 4-N,N-dimethylamino-4-N-methyl-stilbazolium tosylate (DAST) and 4-(N,N-dimethylamino)-4′-nitrostilbene (DANS) dyes on structure, and piezoelectricity of Poly (styrene-co-acrylonitrile) (SAN) copolymer has been studied by several techniques. X-ray diffraction and optical microscopy reveal crystalline phase in the doped copolymer and the degree of crystallinity increases either by increasing dye's concentration or by applying stress to the films. Fourier Transform Infrared spectroscopy (FTIR) spectra showed that the intensity of the vibrational band of SAN copolymer increased with the dye concentration, indicating the interaction between dyes and the copolymer. The dynamic glass transition temperature (T g), probed by Thermally Stimulated Depolarization Current (TSDC), related to the segmental mode of SAN (at ∼373 K) is slightly shifted to lower temperature by adding DANS, while it shifts to higher temperature upon adding DAST (∼390 K). Suppression and enhancing in the current intensity of SAN is related to the dipolar strength of dyes.
ACKNOWLEDGMENT
The authors gratefully acknowledge the Faculty of Science, Mansoura University, Egypt, for the provided facilities during the experimental measurements. One of the authors (H. Elhadidy) would like to thank the CEITEC—Central European Institute of Technology with research infrastructure supported by the project CZ.1.05/1.1.00/02.0068 financed from European Regional Development Fund and thank by Ministry of Education, Youth and Sports of the Czech Republic in the framework of the grant No. CZ.1.07/2.3.00/20.0214.
Notes
Results obtained from data in Fig. .