CUHK Lives and Legends

37 into its cupped leaves too slippery to escape from—SLIPS repel any type of liquid, from oil to water to blood, and prevent organisms like bacteria and barnacles from sticking. SLIPS consist of nanostructured substrates infused with lubricating fluid. The lubricant is locked in place by the substrates and forms a stable, frictionless layer. Tak-sing compared the repellent process of SLIPS to hydroplaning. ‘In a rainy day when you drive on a wet road, the tyre is separated from the road surface by a thin film of water and loses traction, sending your car skidding along the water surface.’ In terms of durability, SLIPS coating even outperforms its natural counterparts due to its self-healing attribute. ‘When an object impacts a liquid, an indent is made on the liquid surface. But once the object is removed, the fluid nature of the water allows it to refill the space that was occupied. Since SLIPS are coated in liquid, they react similarly,’ explained Tak-sing. The range of possible applications for the novel material is endless: it could be used to coat medical devices such as implants to decrease the potential for bacterial contamination, cover the hull of a ship to prevent barnacles from adhering to the surface, and keep aircrafts free of ice to enhance safety and on-time performance. In layman’s terms, we may all cheer when we can liberate the very last dollop of ketchup out of the bottle, or the last bit of toothpaste out of the tube, without sore fingers. Now an Assistant Professor of Mechanical Engineering at The Pennsylvania State University where he heads the Laboratory for Nature Inspired Engineering, Tak-sing hopes to use nature-inspired technologies to address some of the grand challenges in the 21st century, particularly in water sustainability. It involves, for example, developing non-sticky toilet bowls that require very little water to flush, as well as creating super water- condenser to collect clean water from thin air. In April 2017, Tak-sing was named one of the 25 Distinguished Alumni by CUHK’s Faculty of Engineering on the occasion of its silver jubilee. ‘I would never imagine that I would make the list. The Faculty has nurtured numerous talent in the past quarter century. Many of them are making seminal contributions in various sectors. I am honoured to be chosen alongside other highly accomplished alumni.’ He pointed out that as recently as 16 years ago, nanotechnology was considered hardly applicable except, for example, the manufacturing of integrated circuit. ‘But I saw it differently. The natural world is using nanotechnology on a daily basis to solve complex problems, and the strategies have stood billions of years of field-testing. Nature is full of ready solutions to many of the challenges we encounter. Nanotechnology gives us tools to replicate the evolutionary wisdom and make superhuman powers not so superhuman.’ c c Developing SLIPS with Joanna Aizenberg (left) at Harvard University c c Wong Tak-sing (3rd right) with his research group at Penn State University