1. Department of Mechanical Engineering, Advanced Water Research Lab (AWRL), Edmonton, Alberta T6G 1H9, Canada
2. National Research Council Canada (NRC), Nanotechnology Research Centre, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9, Canada
3. Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
4. IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, United States