Engineering Seminar Series 29, 2010: Molecular Mechanics of Defects Cooperativity in Carbon Nanotubes

Dr Goh Kheng Lim, Senior lecturer, School of Engineering, MUSC

Date: 2010-12-10
Time: 12:00 to 13:00
Venue: 9504


Carbon nanotubes (CNTs) are tubular, nanometer-sized structures which are comprised of layers of graphene shells. This class of nanomaterial has unparalleled mechanical properties as revealed by experiments. However, measurements of the mechanical properties of CNTs such as tensile strength revealed a wide range of scattering which could be attributed to structural defects, introduced into a CNT during synthesis or when it is stressed. These defects fall into four categories, namely, topological, rehybridized, incomplete, and doped defects. This talk will focus on a class of topological defects known as Stone-Wales (SW) defects in single-walled carbon nanotubes (SWCNTs). These type of defects can be viewed as the rotation of an sp2 bond through 90° SW rotation to yield a dipole of a pentagon- heptagon pair. The discussion will attempt to show, based on a study carried out using molecular mechanics, how defects interact to influence the mechanical properties of CNTs when these nanotubes are subjected to tensile loads, and to speculate on how defect cooperativity may be exploited for energy storage.

About the Speaker

Dr Kheng-Lim Goh is a Chartered Physicist and Scientist. His PhD degree (University of Aberdeen) was in the area of Bioengineering. He has worked as a research assistant for Prof. Malcolm Pope to study the biomechanics of occupational low back pain at the Liberty Work Safe Centre (Aberdeen, 2001-2) and as a post-doc to investigate the mechanisms of ageing in extracellular matrix (ECM) of connective tissues (Stirling & Cardiff University, 2002-4). In 2005, he moved to Singapore to take up a faculty position as an Assistant Professor at the School of Chemical & Biomedical Engineering, Nanyang Technological University. In 2009, he was appointed as a Senior Lecturer in Mechanical Engineering at Monash University Malaysia. His current research interests include basic and applied studies on fibre composites, particularly on the development of biocomposites for biomedical applications. Dr Goh is a member of the editorial boards of the Journal of Mechanics in Medicine and Biology and the Journal of Medical Imaging and Health Informatics.