SINGAPORE - What makes the teeth of limpets – small sea snails typically as long as a credit card – the strongest known natural materials to date? Even stronger than spider silk, the tiny teeth that line the tongue of these aquatic creatures are so strong that a diamond saw is required to cut them.
Professor Gao Huajian, a Distinguished University Professor at Nanyang Technological University (NTU), has the answer – the teeth’s microscopic structures, which include numerous ultra-fine “nanorods” organised in specific patterns.
This was one of many discoveries by Prof Gao in nanomechanics. For his contributions in this field, he was elected as a Fellow of the Royal Society, the United Kingdom’s national academy of sciences.
Prof Gao, who is from NTU’s School of Mechanical and Aerospace Engineering, joins the ranks of renowned scientists, engineers and technologists around the world, including Stephen Hawking, Isaac Newton, Charles Darwin, Albert Einstein and Dorothy Hodgkin as a member of the prestigious learned society.
He is also the only one of the 80 researchers, innovators and communicators awarded the Fellowship in 2023 to be from a Singapore organisation.
The Royal Society, formally known as The Royal Society of London for Improving Natural Knowledge, is the world’s oldest scientific academy in continuous existence, having been established in 1660. Members are elected for life via a peer review process, on the basis of excellence in science.
Speaking to The Straits Times, Prof Gao said: “It’s every scientist’s dream to join the Royal Society as a Fellow. I was hoping that one day I would, and I was very excited when I found out that I was shortlisted.”
Every year, about 800 candidates are nominated by the society’s existing Fellows, selected according to their “substantial contributions to the improvement of natural knowledge, including mathematics, engineering science and medical science”.
“When I first heard the news of my nomination, I was extremely excited,” recalled Prof Gao, “but I kept it confidential because I wasn’t sure if my election would be successful.”
His research contributions and discoveries in the field of nanomechanics – the study of the mechanical properties of near atomic-scale structures – span nearly four decades. He is frequently inspired by nature, and his findings on limpet teeth lay the groundwork for developing materials that mimic the structure of the teeth, which in turn could be used to develop more effective machining tools.
One of his biggest discoveries was a model he developed in the 1990s to explain how the size of tiny dents made in a material reflect its hardness. This helped industry players with the quality control of electronic components at the time, since making dents was sometimes the only way to test the mechanical properties of small components like computer chips. The 1998 research paper on the model has been cited over 4,400 times.
The American citizen, who previously held positions at Stanford University, Brown University and the Max Planck Institute for Metals Research, was recognised by the American Society of Mechanical Engineers (ASME) with the 2021 ASME Timoshenko Medal, the highest recognition in the field of applied mechanics.
His other accolades include the Guggenheim Memorial Fellowship in 1995; the Rodney Hill Prize in Solid Mechanics from the International Union of Theoretical and Applied Mechanics and the Alexander von Humboldt Research Award, both in 2012; and the 2015 Nadai Medal, the highest recognition of ASME’s Materials Division.
He is also one of the few Singapore-based researchers to be elected by the Royal Society as a Fellow. In 2016, Professor Artur Ekert, director of the National University of Singapore’s Centre for Quantum Technologies, was elected as a Fellow. Dr Stephen Cohen, then chief executive officer of Temasek Life Sciences Laboratory, was elected in 2008.
Prof Gao plans to continue pursuing his research interests and hopes his discoveries will impact society and spur further studies and development of materials that take inspiration from nature.
“In my heart, I’m like a very curious child,” he said, “So I’m always talking to other scientists to understand how things work and, together, we try to push the frontiers of science.”
