Some of the most exciting work to come from Chris Johnson’s thesis was the ability to control the dimensions and contact mechanics of polyacrylamide hydrogels by simply starting with different recipes for the hydrogel in the first place. We already knew that the composition controlled the bulk structure, but now we know it controls the […]
I have started many posts this way, but in fact we keep discovering more reasons. I’m thrilled to share that our recent work shows how hydrogel surfaces have an innate structure that allows them to maintain robust low friction: a gradient layer. When you submerge a hydrogel into a water bath, the polymer chains want […]
The Spring 2022 semester was a whirlwind of activity, and 2 new group members have joined! Nusrat is joining after finishing her undergraduate degree at Bangladesh University of Engineering & Technology (BUET) in Mechanical Engineering. She is focusing her research on the area of permeability of hydrogels and mentors undergraduates. Habib is joining after earning […]
Hydrated gels are very slippery, and we now know it’s partly due to their surfaces! Chris made composite hydrogels with a soft surface skin, then fully characterized the effective stiffness of that layer, contact mechanics, and how it contributes to good lubrication (or not!) He did an impressively-large number of experiments involving materials synthesis, careful […]
Please join me in congratulating Jiho on his new position as a full-time faculty of Mechanical and System Design Engineering at Hongik University. I met Jiho the first week after arriving at Illinois, so my work over the past 7 years and success have always included him, and depended upon him! He graduated in 2020 […]
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 […]
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 […]
Latch mechanisms are one of the most fun mechanical systems, yet we rarely teach about them, or research them. When the ketchup bottle is open and closed, the problem is solved. But what if that little snap didn’t just hold the lid closed, but was designed to snap open a huge structure? That’s what the […]
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 […]
It was beautiful weather, and Shab outlasted us all in the soccer circle. Congrats again! And thanks to Lalith and Jiho for beautiful photos.