Transition to Fall 2021

So many things are changing around here! I’m excited to jump into this new semester with new teaching spaces, new students, and renewed perspective. Look for some announcements in the coming weeks, but generally, things are looking up. Here are a few reasons why: Everyone in the group is fully vaccinated! We can work in […]

New paper out: Hydrogel surfaces are softer than you think! Published in Experimental Mechanics

Hydrogels are inherently slippery — we know this from touching jello and sliding on banana peels. It’s been shown in many of our prior publications, as well as publications from the Sawyer group (University of Florida), the Spencer group (ETH), the tribology group at Imperial College, and many others. However, making polyacrylamide hydrogels in the […]

New paper out: “Cartilage-like tribological performance of charged double network hydrogels”

While we normally work with single-polymer hydrogels, we had the opportunity to work with the Grunlan group at Texas A&M to study their charged double-network hydrogels. These hydrogels are tough! Looking more like cartilage all the time. In this paper we present evidence that their lubrication behavior matches or exceeds that of native cartilage. Higher […]

New paper out: “Compositional Dependence of Polyacrylamide Hydrogel Abrasive Wear Resistance”

Many researchers are aware that hydrogels, even a single kind of hydrogel (polyacrylamide) can be designed to have properties that range from brittle to viscoelastic. It’s truly a versatile material! As hydrogels are being considered as replacements for cartilage in the body, they need to be able to take a beating: they can’t break under […]

Congratulations to Shab on her successful PhD defense on Friday! “Wear mechanisms of chemically crosslinked hydrogels under mild abrasion”

Hydrogels are the next “engineering material” that we need new textbooks for, to teach the next generation of engineers to design with them. Shabnam’s work contributes directly to that, and over the past 4 years she has discovered that the material nature of the hydrogel determines how it wears away — sometimes it acts brittle, […]

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. […]