1. Polymers and Functional Materials Division, Indian Institute of Chemical Technology, Council of Scientific and Industrial Research; Tarnaka, Hyderabad 500 007 India
2. Present address: Department of Chemistry; University of Massachusetts Lowell, One University Avenue; Lowell Massachusetts 01854
3. Reverse Osmosis Membrane Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research; Bhavnagar 364002 India
4. Academy of Scientific and Innovative Research, Indian Institute of Chemical Technology, Council of Scientific and Industrial Research; Tarnaka, Hyderabad 500 007 India