1. Department of Polymer Technology; Tshwane University of Technology; CSIR campus Pretoria Republic of South Africa
2. Department of Physics; University of South Africa; Private Bag X6 Florida 1710 South Africa
3. Center for Advanced Biomaterials for Health Care; Italian Institute of Technology@CRIB; Napoli Italy
4. Department of Polymer Science and Engineering; Pusan National University; Busan South Korea