Hong Yee Low, Biomimetic Surface Functionalities via Nanoimprint Technology
Date: Mon 8 Dec 2014, 13:00 - 14:00
Location: SEMS Seminar Room
Biomimetic Surface Functionalities via Nanoimprint Technology
Hong Yee Low
Engineering Product Development
Singapore University of Technology and Design
20, Dover Drive, 138682, Singapore
Institute of Materials Research and Engineering
Agency of Science, Research and Technology
3, Research Link, Singapore 117602
Many biological species in nature are endowed with unique surfaces that provide them with survival ability. For example, the beautiful rose petal has a strong water adhesive surface so that dewdrops are captured and serve to magnify its beauty; this unique characteristic helps the flower to attract insects for pollination purpose. Moth has anti-reflective eyes that help them to avoid being detected by predators at night; moth eyes are covered with many small lenses to gives it the anti-reflective function. There are many such examples. To learn from the biological species is to be able to copy or synthetically mimic the surfaces onto engineering materials. Mimicking the surfaces and the corresponding functionalities onto engineering materials provides a non-chemical approach to new material properties. Many of the unique characteristics of biological species are attributed to the sophisticated surface morphology on the surfaces of leaves, petals, insect legs and wings. These surface morphologies often consists of both micrometer and nanometer textures arranged hierarchically.
Nanoimprinting process has similar working principle as traditional polymer embossing process, but with the precision to emboss nanoscale surface topography. Using nanoimprinting technique, we have fabricated a variety of biomimetic surfaces and the corresponding properties on polymers. For example, lotus-leaf and rice-leaf mimetic superhydrophobic surfaces, butterfly wing mimetic structural color effect and gecko-foot mimetic dry-adhesive property were achieved on nanoimprinted polymer films. It is also worthwhile to note that a more important lesson provided by natural surfaces goes beyond mimicking their structure, and into the realm of design. Taking the design cues from nature, we achieved tunability of surface properties using a combination of explicit geometrical design and careful selection of the intrinsic properties of the material.
In contrast to traditional surface modifications (e.g. chemical grafting, coating, etching or plasma treatments), using surface topography to impart new functionalities makes it possible to alter, enhance, or improve product function without changing the chemical nature of the materials. For applications in biomedical technologies, each time a new chemical method is introduced, a lengthy regulatory approval is needed before the new product can be used. As a result, the development of new products can be costly and time-consuming. We have further demonstrated the gecko-foot mimetic dry-adhesive as a glue-less adhesive patch for surgical use and the potential for scaling up the biomimetic films through roll-to-roll nanoimprinting process development.
Hong Yee Low received her PhD from Case Western Reserve University in 1998, in the area of polymer science and engineering. She spent about 2 years in Motorola Semiconductor Sector working on the projects related to packaging of semiconductor chips. She then joined the Institute of Materials Research and Engineering (IMRE) in late 2000. In her 13 years at IMRE, she held various responsibilities including the principle investigator for nanoimprinting research, program manager for the Industrial Consortium on Nanoimprint Technology (ICON), the group head for the Patterning and Fabrication Group and the director for research and innovation. In the topic of nanoimprinting, she has co-authored more than 60 journal publications and more than 20 patents (granted and pending).
She collaborates actively with academia and industries. Some of her past and present collaborators are Prof. Gleb Sukhorukov (Queen Mary College of London), Prof. Evelyn Yim (National University of Singapore) and Prof. Kian Ping Loh (National University of Singapore), Sumitomo Chemicals (Japan) and Johnson & Johnson Medical and Diagnostic (USA). Through a collaboration with Dr. Frank Chan at the Temasek Polytechnic (Singapore), a technology for 3-D display achieved via nanoimprinting was spun-off by Nanovue Pte. Ltd. (Singapore).
In 2013, she joined the Singapore University of Technology and Design (SUTD), a university co-established with Massachusetts Institute of Technology (MIT) in 2010.