BETHLEHEM, Pa.—The National Science Foundation has granted Lehigh University nearly $2 million in funding over five years to work with Michelin North America and Cornell University to develop "novel" mechanisms to improve the friction of soft materials.
Such research, according to Anand Jagota, professor and founding chair of Lehigh University's bioengineering department, could have wide-ranging implications for society, in the form of tires that make cars safer, improved robots' ability to grasp and perform intricate tasks or building a better-performing table-tennis racket.
The partners will look at "bio-inspired design" of near-surface structures to enhance the understanding of friction.
"These are two difficult and new approaches to controlling friction of soft material surfaces and interfaces that have come to light through our previous work," Jagota said. "This is our fifth and largest grant in this line of research—we continue to find fresh and exciting ideas to investigate."
"The ability to use surface features to control the friction between surfaces opens many design possibilities," Mike Andrews, director of external research for Michelin North America, said, "but in order to take advantage of the idea, we need to understand the mechanisms involved and that is what this research will allow us to do."
"With this substantial funding, the manufacturing expertise and resources from Michelin, and our university's ecosystem of support for industry-oriented grad studies, we'll be able to give students a solid understanding of how industry-driven research works," Jagota said.
Jagota, who is affiliated with Lehigh's Institute for Functional Materials and Devices (I-FMD), will continue his long-standing collaboration with Chung-Yuen Hui, a Cornell engineering professor. The team also includes 2008 Lehigh alum Constantine Khripin, a materials performance researcher at Michelin who did his dissertation work in Jagota's lab.
"As a PhD student, I was on the academic side of research, discovering new phenomena and attaining an in-depth understanding of mechanisms involved," Khripin said. "Now that I am on the industry side, there's more to the equation. I have to be part salesman and part diplomat, pitching the academic results to a broad organization for funding; part engineer, identifying applications where the project might bring value; part paralegal, working on the IP strategy; part contract negotiator…It's exciting to be involved with connecting research to product innovation, but there are certainly a lot of moving pieces."
One of Jagota's current PhD students who works on the lab's existing GOALI project with Michelin, Nichole Moyle, said participating in an industry-academic partnership has given her insight into the commercial applications of her research.
"You get an idea of how easy or challenging it would be to apply an idea from the lab on an industrial scale," said Moyle, who is investigating ways to increase the sliding friction of lubricated soft materials by using structures to store and then unstably release energy.
"Many of the structures we work in our lab with are on the micron scale," she added, "but for my project, we also look at structures on the millimeter scale, because those would be easier to manufacture. We also meet with our industry partners multiple times a year, so there are many opportunities to practice presenting and discussing our work."
The journal Soft Matter has accepted for publication the team's first paper on research partially funded by the new grant.
The funding comes as a Leading Engineering for America's Prosperity, Health, and Infrastructure (LEAP HI) Grant Opportunity for Academic Liaison (GOALI).
The LEAP HI program supports interdisciplinary, multi-investigator proposals tackling complex engineering problems and "challenges the engineering research community to take a leadership role in addressing demanding, urgent, and consequential challenges for advancing America's prosperity, health and infrastructure."
Jagota has partnered with Michelin North America previously, through the NSF's GOALI program, which encourages academic-industry collaborations. This is the first LEAP HI grant awarded to a Lehigh researcher since the program's inception in 2017.
Jagota, who also a professor of chemical and biomolecular engineering, said the new LEAP-HI GOALI project has origins in earlier work in biomimicry—investigating the biological adhesion mechanisms in geckos, lizards, and frogs—but has evolved to a collaboration with industry focused primarily on friction.
"In making these biomimetic surface structures, employing fibrils or complementary shapes, we've been able to create very high sliding friction, which could be used to improve the braking performance of tires," he said.
"We've discovered several techniques that can turn friction up or down. Now we're taking a deeper dive into these mechanisms, some of which are meso-scale versions of molecular level phenomena that underlie the fundamental question of how friction arises between surfaces in the first place."
This project, he said, will investigate two mechanisms based on previous discoveries—"meso-scale dislocation arrays" and a new form of elastic hysteresis.
Meso-scale dislocation arrays are interfaces with a periodic array of features that accommodate misorientation by generating meso-scale interfacial dislocations, which can be used to control friction. Employing these arrays in the production of tires and other products comprised of layers of soft materials like rubber, could improve product quality, cut down on waste, and open up experimentation with new materials, the research team claims.
A new form of elastic hysteresis, which is discussed in the Soft Matter article, is based on periodic near-surface patterning of elastic modulus, which can be used to set up additional hysteresis to yield significant friction enhancement. The mechanism could enhance friction of tires, especially in wet conditions, and contribute to a reduction in the risk of vehicle collisions and related fatalities.
The experiments Jagota's team will perform and the data they will analyze will expand engineers' understanding of friction while generating ideas and methods that could influence Michelin's tire design and production in the future.
"Tire manufacturing is a very mature field, so there's a very different dynamic when it comes to implementing innovation," he said. "You have to be very, very careful before making changes because of the safety aspect, so there is a deliberate process for applying new ideas. It's certainly a challenge, but we take that as a positive."
The project also is aligned with Lehigh's Pasteur PhD Partners (P3) Fellowship, a student-centric graduate training model that provides doctoral candidates in the P.C. Rossin College of Engineering and Applied Science with long-term, hands-on industry experience and mentorship. P3 is backed by an NSF Innovations in Graduate Education (IGE) award and led by principal investigator and professor of materials science and engineering Himanshu Jain, with Mr. Jagota serving as a co-PI.