The more you learn about hydrogels, the weirder they become. They take their shape from water, but act as a brittle solid when you try to break them in your hands. However, they are also quite stretchy. These contradictions are sorted out a bit in Shab’s new paper “Brittle or Ductile? Abrasive Wear of Polyacrylamide […]
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 […]
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 […]
As soft robots are the new normal, polydimethylsiloxane, or PDMS, is becoming ubiquitious in labs. You know it as the material that makes “sticky hands” you throw against the wall, and it can be a clear, or slightly cloudy (turbid) soft solid. It can be molded into any shape conceivable, especially shapes with more than […]
Lihua worked hard with the Wissa group and Alleyne group to identify part of the mechanism of the click beetle hinge, and friction effects of diffraction grating features on insect cuticle. Congratulations Lihua!
We have sought the answer to this question for years! In fact, I started working with contact lenses as an undergraduate at Florida in Greg Sawyer’s lab. Our answer at the time was “chemistry.” Our answer through the years shifted to consider structured surface layers, polymer fluctuation, and hydration, among others. But it is just […]
Congratulations to Jiho on his contact measurements to provide some baselines of properties of PDMS to help with Professor Hutchens’ work on soft fracture using cavitation rheology! And if you are new to the word, just imagine inserting a needle into your jello and blowing a hole in it! This paper can help predict the […]
When you see these images of the beetle peg morphology, doesn’t it make you wonder about the contact mechanics? Us too! In this work by Ophelia and Lihua, we describe how the snap of the click beetle is enabled by the rigid peg. But we also say that the contact mechanics matter. So interesting how […]
How does a high-water-content hydrogel surface respond to step changes in speed? Jiho measured the lubrication mechanics of a complex shear interface through tribo-rheometry to try and figure it out. Out of all the possible responses, we find a combined time-dependent and shear-thinning response, just like a complex fluid. Check it out for more details.
Prof. Dunn presented Erik’s work “Slip versus Flow: Driving Hydrogel Lubricity against an Impermeable Probe” as a poster at the 2016 Soft Matter Symposium at the University of Florida. A great meeting for anyone in soft matter!