Abstract: The need to understand friction fundamentally at the microscale is increasingly important in technologies as diverse as soft robotics and consumer products. The first part of the talk focuses on the role of particle roughness in the rheology, structure, and dynamics of dense colloidal suspensions. Recent work from our group showed that the shear viscosity and linear viscoelasticity of such particles can be explained by their unique ability to form contact networks in dense glassy suspensions. The second part of the talk will focus on our work on haptic materials, where we investigate how patterned and poroelastic materials affect fluid friction. A semi-analytical model based on lubrication analysis can explain the sliding friction for patterned surfaces of many materials, such as elastomers, thermosets, and hydrogels in sliding conditions. Importantly, the model works for haptic friction experienced by robotic and human fingers. This framework continues to expand a foundation that informs the engineering of manufactured surfaces and automated systems, and furthermore opens up the creative design of friction for human machine operations in real-world conditions.

Bio: Lilian Hsiao is an assistant professor of Chemical and Biomolecular Engineering at North Carolina State University and the founding scientist of X-MED Hydrogels. She received her B.S. in Chemical Engineering from the University of Wisconsin-Madison in 2008 and her Ph.D. in Chemical Engineering from the University of Michigan in 2014. She received the Rackham Predoctoral Fellowship for her work with Michael Solomon on the microstructure of colloidal suspensions in flowing systems. Her postdoctoral training at the Massachusetts Institute of Technology with Patrick Doyle was on colloidal nanoemulsions and 3D printing. She started her tenure-track position at NC State in 2016. Hsiao has been recognized for advancing the fields of suspension rheology and soft haptic materials, most recently through the ACS Unilever Award, the NSF CAREER Award, and the AAAS Marion Milligan Mason Award.

All seminars are held on Wednesdays from 12:00 noon-1:00 p.m. in the Bowen Hall Auditorium Room 222. A light lunch is provided at 11:30 a.m. in the Bowen Hall Atrium immediately prior to the seminar.