Can materials be both soft and tough? Historically, low toughness has severely limited implementation of soft materials, such as hydrogels, in emerging technologies. Our perspective “Pathways to tough yet soft materials” analyzes state-of-the-art techniques for enhancing mechanical properties of hydrogels. In this article, published in the latest issue of Science, postdoc Nikola Bosnjak discusses novel methods for achieving such material features, including unfolding of mechanophores and sliding of highly entangled polymer chains. We lay out chemical and physical strategies for further toughening of soft materials, and propose physics-based models as a tool to facilitate development of such materials.
Dr. Michael Buche’s paper on statistical mechanics derived modeling of mechanoresponsive elastomers is now out in the Journal of the Mechanics and Physics of Solids. Titled “Chain breaking in the statistical mechanical constitutive theory of polymer networks,” it methodically derives a constitutive model for elastomer networks with breakable bonds that encompasses and expands beyond the existing theories of transient networks and irreversible rate independent bond fracture.
In collaboration with the Kilian and Kruzic groups at the University of New South Wales, Michael also extended this model and applied it to a novel double network hydrogel that releases small molecules in response to applied load. This approach could be used to create implants with load responsive drug release. This second paper, “Force-mediated molecule release from double network hydrogels” is now published in Chemical Communications.
We’re a bit behind on posting, so here’s a bunch of MMD lab updates in one.
We have two new collaborative papers out: “Microstructural evolution of polyurea under hydrostatic pressure” in Polymer with the Fors group, contributed to by PhD student Steven Yang, and “Digital light processing of liquid crystal elastomers for self-sensing artificial muscles” in Science Advances with the Shepherd group, contributed to by PhD Student Joy Zhang.
Finally, check out this month’s imechanica blog by Prof Silberstein and PhD student Max Tepermeister on electromechanics of polyelectrolytes.
Congratulations to now officially PhD candidate Max Tepermeister for passing his qualifying exam and to no longer PhD candidate Michael Buche for successfully defending his thesis!!!!
MMD lab undergraduate Shreya Gowda won the prestigious Brooke Owens fellowship. See here for the department spotlight on her.
Welcome to Nikola Bosnjak and Max Tepermeister who joined the MMD lab this fall. Nikola is a postdoc who recently completed his PhD at NJIT on mechanics of gels. Max is a first year PhD student in the mechanical engineering field.
Click here to see the Cornell Research highlight of the Silberstein group work.
MMD Lab’s First Paper on Modulating Polymer Mechanical Properties with Electric Fields Now Published
“Can Polyelectrolyte Mechanical Properties Be Directly Modulated By an Electric Field? A Molecular Dynamics Study” has just been published in Advanced Functional Materials. This study was carried out by first author Prathamesh Raiter who just completed his MS in the lab, and the concept came from former postdoc Yuval Vidavsky. Using molecular dynamics, this work shows that the bulk mechanical properties of polyelectrolytes can be modulated by the application of electric fields. The dominant mechanisms responsible for the stiffening and strengthening in the explored systems are chain orientation, chain extension, entanglement density and electrostatic interactions. These functional materials have potential applications within the soft robotics and energy fields.
Congratulations to Shreya Gowda for winning an Engineering Learning Initiatives undergraduate research award for her project “Dynamic Bond Approach to Improving Resin Transfer Molding Composites”!
Congratulations to Prof Silberstein for winning the Wolfgang Knauss Young Investigator Award from the Society of Experimental Mechanics (https://sem.org/awardsknauss). This award is given biannually by the SEM in recognition of an individual who has made significant research contributions to the broad field of experimental mechanics, with a focus on time dependent materials. Prof Silberstein’s award is for “significant contributions in the areas of macromolecular tailoring, mechano chemistry, and the mechanics of polymeric nanofiber networks and developing constitutive models based on novel experimental techniques.” Many thanks to Prof Liechti for shipping the award since SEM was virtual this year.