Our latest paper “Engineering bacterial biomanufacturing: characterization and manipulation of Sphingomonas sp. LM7 extracellular polymers” is now published in RSC Soft Matter. This study was spearheaded by Ellen van Wijngaarden in collaboration with Prof. David Hershey’s lab at Wisconsin-Madison. We identified the material properties of a novel polysaccharide, Promonan, and demonstrated improved thermal stability and material stiffness compared with similar bacterial polysaccharides currently used in industry. Our study also explored changing the material composition through alternative processing methods to reduce production time by over 50% and tune the material stiffness for possible applications in bioprinting, bioremediation, and healthcare. 

MMD lab’s emerging collaboration with Prof Ben McDonald of Brown University’s Chemistry Department has its first publication! PhD candidate Hongyi Cai lent his expertise in mechanical testing of polyelectrolyte elastomers and gels to help enable “Ion-Specific Interactions Engender Dynamic and Tailorable Properties in Biomimetic Cationic Polyelectrolytes.”

Ionic diodes, created at the intersection of polymers with different fixed charges, form the core of many ionic devices. Despite this centrality, the time dependent behavior of these diodes is not well understood. In a new paper published in Advanced Sensor Research and led by PhD candidate Max Tepermeister, we use a finite-volume based continuum simulation to explain how geometry and material properties influence each stage of a diodes transient response. We show that how a diode connects to a larger circuit can dramatically change its performance, and we develop a consistent set of metrics to quantify these differences and provide a basis for future device comparisons. Using what we learned, we make recommendations for tuning performance by changing how diodes are built.

Our research paper “Elucidating the impact of microstructure on mechanical properties of phase-segregated polyurea: Finite element modeling of molecular dynamics derived microstructures” is now published in Mechanics of Materials. This study was led by Dr. Steven Yang, who recently completed his PhD in the lab, in collaboration with Dr. Stephanie Rosenbloom and Prof. Brett Fors from Cornell Chemistry. We developed a modeling framework to uncover how the phase-segregated nanostructure of polyurea influences its mechanical properties. This work integrates a wide range of methodologies, including molecular dynamics and finite element simulations, constitutive theory, and both mechanical and X-ray scattering experiments.

https://doi.org/10.1016/j.mechmat.2023.104863