Less Is More
Reducing friction with nano-technology to better our world
An International Expert in Surface Engineering Works to Improve the Efficiency of Everyday Items by Coating Surfaces with Nano-Structures
Words like tribology and hydrophobicity mean little to most people, yet research in these areas – the study of friction, wear, and lubrication and the ability of a substance to repel water, respectively – improve the tools we use every day.
Min Zou, a mechanical engineering professor at the University of Arkansas, is recognized as an international expert in both fields. That’s why in August the National Science Foundation awarded the university a $24 million grant to lead the new Center for Advanced Surface Engineering, a collaborative effort comprising 40 faculty members from 10 institutions, to advance this field and build industry partnerships.
Zou specializes in developing nanomaterials to texturize surfaces of commercial products and electro-mechanical systems to reduce friction and improve energy efficiency. Her work is gaining national attention for improving everything from electronic devices to tissue engineering and even everyday kitchen skillets.
"Polytetrafluoroethylene is a big, scary word," Zou said, explaining the technical name for the polymer commonly known as Teflon. "It's simply a material layer or coating – we call it a film – that essentially does not stick and is hydrophobic, meaning it repels water. Our goal is to make it even more water repellent."
Zou led a team of researchers who discovered a way to do exactly that, to make Teflon even more slippery. They treated thin films of the polymer with copper nanoparticles and found that the lubricating material significantly reduced both wear and friction. Her technology has also been used in further research on cell growth in tissue engineering.
These nanostructures — called core shell structures — can be incorporated into solid surfaces where mechanical integrity of nanostructures is vital. They consist of a metallic core covered by a hard shell made of various nanoscale material such as silica. Their layering properties allow the particles to hold their shape after being subjected to extremely high friction.
"Core-shell nanostructures have many novel properties – optical, magnetic and catalytic," Zou said. "Recently, my group discovered that these structures also have novel mechanical properties – unusually high strength and deformation resistance, for example – and thus can be incorporated into solid surfaces for many applications where mechanical integrity of nanostructures is of paramount importance."
That discovery has led to millions in federal grants for Zou to advance her research this year alone.
In early 2015, Zou received a $438,317 grant from the National Science Foundation to identify the fundamental deformation mechanisms of a new type of nanoscale material that she and her team discovered. Exceptionally strong and resistant to deformation, the surface texture material reduces friction and heat to improve the mechanical durability of computer hard-drives and other electronic devices.
The $24 million grant from NSF that followed this summer enables the University of Arkansas to partner with industries and create new products for manufacturing, aerospace, defense, agriculture, oil and gas, food packaging and healthcare industries.
The center will include four interdisciplinary research teams from multiple institutions and integrate industry partners into the curriculum through internships and seminars.
As part of the NSF’s Experimental Program to Stimulate Competitive Research — EPSCoR — which promotes scientific progress nationwide through partnerships across the public and private sectors, the center will establish start-up companies to commercialize technologies developed by its researchers and create new products and jobs.
One such company, WattGlass, is working to commercialize anti-reflective, self-cleaning coatings for solar panels and other glass applications that were developed by Zou and two graduate students during previous EPSCoR-funded research.
The coatings spread water rapidly across glass, creating a surface that is both self-cleaning and anti-fogging as water doesn’t bead up. The coatings also reduce reflection from the glass, making solar cells more efficient.
Earlier this year, WattGlass received a $150,000 grant from NSF to further develop these nanoparticle coatings for large-scale projects using commercial coating equipment.
"Micro- and nano-electro-mechanical systems hold great promise to revolutionize nearly every product category, from computer hard drives to automotive and biomedical devices," Zou said.