1. Department of Polymer Science and Rubber Technology Cochin University of Science and Technology, Cochin 682 022, India, S. D. College, Alappuzha, India
2. Department of Polymer Science and Rubber Technology Cochin University of Science and Technology, Cochin 682 022, India,
3. Department of Physics, Cochin University of Science and Technology Cochin 682 022, India
4. Department of Electronics, Cochin University of Science and Technology, Cochin 682 022, India