ELMI student symposium

Bex Pendrak, Ellen van Wijngaarden, Si Chen, and Prof Silberstein all participated in the first annual ELMI student research symposium last week. See below for proof of pizza.

New paper on solvent free ionic conductivity out in Macromolecules

Metal–ligand coordination, as a non-covalent interaction, has been extensively applied in polymer matrices to enhance the mechanical toughness, tune viscoelasticity, and enable self-healing. In recent years, metal–ligand coordination has also been studied as a means of designing ionically conductive polymers. Silicone is a widely used elastomer due to its low cost, large strain to failure, and excellent chemical resistance. However, its poor ionic conductivity limits its application in many fields, including electrochemical devices, batteries, and fuel cells. In “Understanding How Metal–Ligand Coordination Enables Solvent Free Ionic Conductivity in PDMS“, we show that the incorporation of metal-ligand complexes into silicone can enhance its ionic conductivity without the need for a solvent and investigate the fundamental mechanisms governing this conductivity, using in-depth experimental studies with fully atomistic MD simulations. Our work provides insights into the strategic design of ionically conducting polymers that would benefit a range of applications. This effort was led jointly by MMD lab PhD graduate Xinyue Zhang and soon to be MS graduate Jinyue Dai, and in collaboration with Max Tepermeister, Prof Jingjie Yeo, and Yue Deng from the Archer lab.

Congratulations Bex

Congratulations to soon to be MMD lab alum Bex Pendrak for achieving honorable mention for the highly competitive NSF Graduate Research Fellowship Program! Bex will be starting a PhD program in the fall.

Solid or liquid?

On March 3rd, 2023, Postdoc Rob Wagner and Ph.D. candidate Zhongtong Wang, in conjunction with the Cornell Center for Materials Research, attended Dryden Elementary School to teach 3rd-grade students about the phases of matter, and viscoelastic materials. In this interactive lesson designed by Rob, Rob and Zhongtong used hands-on demonstrations spanning from rubber bands and maple syrup, to silly putty, ooblek, and shaving cream to teach the kids about the principles of elasticity, viscosity, and what happens when materials can have both! The lesson ended with a set of video demonstrations and open Q&A pertaining to some of Rob’s Ph.D. research on the mechanics of fire ant rafts, thus highlighting the creative ways researchers may use traditional material science concepts in the exploration of rich, yet widely untapped dynamic, active, and living materials. By allowing the students to make observations, postulate hypotheses, and then openly discuss the root causes of properties in these unusual materials, Rob and Zhongtong sought to spur curiosity, scientific reasoning, and a broader interest in STEM amongst these promising young minds!

Paper on modeling elastomers with ionic bonds and entanglements out in Mechanics of Materials

Dynamic crosslinks and entanglements play a significant role in tuning mechanical properties of elastomers and gels. In our recent paper in the journal of Mechanics of Materials, we report a continuum modeling framework that considers these two mechanisms for adding toughness and strength to polymers – ionic bonding and entanglements. This theoretical study led by Zhongtong Wang investigates these mechanisms in the context of bulk polyelectrolyte mechanical properties. This work firstly establishes the constitutive model that couples entanglement evolution with the ionic crosslink effects and ionic bonds provide strength and dissipate energy without stiffness loss. This theoretical framework could direct the design of customized materials for various applications.  

ELMI website updated!

The Engineered Living Materials Institute website is now live. Please check out our new institute home: elmi.cornell.edu.

Congratulations to Nikola!

Congratulations and good luck to Nikola Bosnjak for his new job at Nike!

Congrats to Zhongtong Wang!

Congratulations to mechanical engineering PhD candidate Zhongtong Wang for passing his A-exam earlier this week! Zhongtong’s PhD will be on “Constitutive Modeling of Polymers and Polymer Composites with Dynamic Bonds.”

Silberstein lab goes to IMECE

Mechanical engineering PhD students Max Tepermeister and Zhongtong Wang, and MS student Jinyue Dai all presented at ASME’s International Mechanical Engineering Congress and Exposition in Columbus, Ohio last week.

Publication on ionically crosslinked elastomers is out in Soft Matter

Incorporation of reversible crosslinks into polymers is an effective approach for tailoring their mechanical properties and to realizing behavior like self-healing, shape memory, and pH sensitivity. Among various reversible crosslink types, ionic bonds are particularly interesting because of their biocompatibility, saloplasticity, and relevance for energy conversion technologies. Understanding the structure-function relationship of such polymers is important for future development of advanced materials. In our latest paper, led by PhD candidate Hongyi Cai, we address this question by designing and characterizing a series of highly stretchable elastomers inspired by polyelectrolyte complexes. We demonstrate how ionic bonds formed among polymer chains strengthen the elastomers and also help them recover.