1. Institute of Science Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Malaysia;, Email: tunkuishak@yahoo.com
2. Institute of Science Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Malaysia
3. Advanced Materials Research Center (AMREC) SIRIM Bhd, 09000 Kulim, Malaysia