New paper: “Similarity of internal and external friction: Soft matter frictional instabilities obey mean field dissipation through slip avalanches”

We usually think of hydrogels as slippery and wet — that’s their definition! But if a probe pushes on them to a higher pressure before applying lateral slip, that high pressure causes unstable friction, or stick-slip (just like the elastomer in our prior post!). So even inherently low-friction materials relieve interfacial strain in extreme ways. […]

New Paper: “Precise Correlation of Contact Area and Forces in the Unstable Friction between a Rough Fluoroelastomer Surface and Borosilicate Glass”

Last year I had the privilege of hosting the now Dr. Chao Wang in my lab to use our optical in situ microtribometer to study the stick-slip behavior of seal elastomers. He obtained a supporting fellowship from the Austrian Marshall Plan Foundation, and used this work toward his PhD in Polymer Tribology from Montanuniversit√§t Leoben. […]

New paper out: Generalized model linking rheology and soft matter tribology

We describe the resistance to slip of an interface as friction, and the origin of that friction can vary widely: roughness, plasticity, lubrication, temperature, etc. Some of those originating mechanisms can also change with time: asperities flattening, lubricating migration, or other things. The way that people have tried to quantify those changing mechanisms is to […]

Congratulations to Jiho on earning his PhD!

We’ve had a bit of a hiatus in publicizing our work, but we’re back! The first big congratulations goes to Jiho, who defended his dissertation in the middle of a raging worldwide pandemic. He successfully presented from his residence, his dissertation entitled “SOFT HYDRATED SLIDING INTERFACES AS COMPLEX FLUIDS.” Jiho moved very quickly to a […]

Local properties of oriented tissues – you can still use indentation!

Microindentation is a useful technique for assessing the local properties of soft materials. But applying an appropriate contact model and extracting those properties is a more complex matter, especially for anisotropic biological tissues like tendon. Do not despair! Jiho worked with the Wagoner Johnson Lab to demonstrate the elliptical contact areas between a spherical probe […]

Multifunctionality of insect cuticle: friction and optics

Insects did it first! Inspired by beetle iridescence and a scientist who has studied them (Ainsley Seago), the ABC Lab, the INHS Insect Collection, and the Materials Tribology Lab teamed up to study the multifunctionality of insect cuticle. Back down the evolutionary tree of beetles, some species developed iridescent cuticle, and others did not. This […]

Tribology Lab descends on TFC 2019

We all went up to Chicago for the Tribology Frontiers Conference at the Drake Hotel in Chicago – even Helen, our undergraduate! We had a great time hearing about work and making new connections, as well as getting critical feedback on our own work. Prof. Dunn gave an invited talk at the ASME Feature session, […]