Congratulations to Rebecca! Our paper “Mechanically active materials in three-dimensional mesostructures,” in collaboration with Xin Ning, John Rogers, et al., is now online in Science Advances, and highlighted as a featured article.
The key idea is to combine advanced manufacturing and mechanics to integrate multiple, independently addressable piezoelectric thin-film actuators into complex, 3D mesostructures. Among the many possible uses, in this work we demonstrate the ability to measure viscosity and density of surrounding fluids.
The work is a tour de force of new theoretical derivations, first-of-their-kind model fitting to experiments, and new molecular insights for a transient polymer network.
We employ the concept of a parameterized continuous spectrum, which can dramatically reduce the number of fit parameters of a model, resulting in a model that is more credible, and with more certainty on parameter values for inferring molecular information.
The framework can be applied generally to a vast library of existing mathematical models (Corotational, Giesekus, etc.). The work demonstrates the potential of using weakly nonlinear oscillations, a developing area of characterization also known as medium-amplitude oscillatory shear (MAOS), to understand complex fluid and soft matter rheology.
Congratulations to Jonathon and our collaborators Yong-Hoon Lee and James Allison (UIUC, ISE) on receiving a 2017 Journal of Mechanical Design Editors’ Choice Award – Honorable Mention.
The award was given in Quebec City, Canada, at the annual ASME International Design Engineering Technical Conference.
Our paper (DOI link) describes design optimization with viscous Newtonian fluids and arbitrary surface shapes for reducing friction in sliding contacts. The approach goes beyond simple textures considered in the literature (dimples, wedges, etc.) and instead considers an arbitrary continuous texture geometry represented using a two-dimensional cubic spline interpolation. This results in significant improvement in performance with the best designs, which are textures resembling a spiral blade.
The results have implications for thrust bearings, hydraulic systems, and anywhere that textured surfaces can be used to reduce friction and improve energy efficiency in engineered systems.
Congratulations to Arif on our recent collaborative paper with Liu et al. “Dynamic Remodeling of Covalent Networks via Ring-Opening Metathesis Polymerization” DOI link
Led by the Moore Group (UIUC, Chemistry), we report a fascinating system which reversibly changes from solid polymer network to liquid monomers, and back again, controlled by temperature. Rheology helps to characterize and understand the reversible process.
The ability to “remodel” a material is used throughout biology for resiliency and maintenance. Our work here represents a promising candidate for a synthetic engineered material that can remodel itself.
Samya Sen has been awarded a PPG-MRL Graduate Research Assistantship. This is a competitive award that will support his research goals to understand how rheologically-complex fluids stick, splash, and coat surfaces upon impact.
Reaching out to the industries where rheology is important, Prof. Ewoldt (along with Prof. Gareth McKinley (MIT) and Prof. Vivek Sharma (UIC)) recently presented an Advanced Technology Webinar to members of The Adhesive and Sealant Council. Prof. Ewoldt presented work on “Rheological unicorns: mapping and designing extensible yield-stress fluids.” Event information here.