1. Department of Chemistry, Sri Krishnadevaraya University, Anantapur, Andhra Pardesh 515 003, India
2. Department of Polymer Science and Technology, Sri Krishnadevaraya University, Anantapur, Andhra Pradesh 515 003, India
3. Department of Physics, Rayalaseema University, Kurnool, Andhra Pardesh 518 002, India