Optical and electrical properties of swift heavy ion beam-irradiated polycarbonate/polystyrene bilayer films

Abstract

Polycarbonate/polystyrene bilayer films prepared by solvent-casting method were irradiated with 55 MeV carbon ion beam at different fluences ranging from 1×10¹¹ to 1×10¹³ ions cm⁻². The structural, optical, surface morphology and dielectric properties of these films were investigated by X-ray diffraction (XRD), UV–visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, optical microscopy and dielectric measurements. The XRD pattern shows that the percentage of crystallinity decreases while inter-chain separations increase with ion fluence. UV–visible spectroscopy shows that the energy band gap decreases and the number of carbon atoms in nanoclusters increase with the increase in ion fluences. The refractive index is also found to decrease with the increase in the ion fluence. Optical microscopy shows that after irradiation polymeric bilayer films color changes with ion fluences. The FTIR spectra evidenced a very small change in cross-linking and chain scissoring at high fluence. Dielectric constant decreases while dielectric loss and AC conductivity increase with ion fluences.

Keywords:

• swift heavy ion
• bilayer
• energy band gap
• refractive index

Acknowledgements

The author gratefully acknowledges the financial support of Inter University Accelerator Center (IUAC), New Delhi, India through UFUP project for pursuing this work. I am much indebted to Dr Shweti Singh Rathore for some useful discussion. I am also grateful to staff members of IUAC, New Delhi for their help during irradiation and other experimental investigations facilities.