Date/Time
Date(s) - 11/28/2023
3:00 pm - 4:00 pm
Location
Rhines Hall 125
Categories
Abstract
We are fascinated by the complex fluid beauty and the challenges underlying the design and use of plant-based foods and sustainable formulations, including paints and coatings, fibers, cosmetic creams, nail lacquers, and personal care products like hand soaps, shampoos, and conditioners. The need to provide food and better living to the exploding world population promises to exacerbate climate change due to the high carbon cost per calorie and non-biodegradable products. Plant-based foods and formulations offer promising alternatives; however, their suitability as sustainable substitutes will require emulating properties, processing, and functionalities of the animal- and fossil-fuel-based products.
Flow behavior, stringiness, spinnability, and printability of formulations are often assessed qualitatively by dripping from a nozzle or a ladle or by stretching a liquid bridge between two surfaces (thumb and forefinger or between parallel plates). The handy tests examining the pinching time of a columnar neck undergoing spontaneous capillarity-driven pinching and extensional flows correlate better with stringiness and dispensing behavior than shear rheology characterized using torsional rheometers. However, well-documented challenges arise for the quantitative characterization of extensional rheology response, leaving unanswered questions about the influence of macromolecular properties on rheology, processing, and sensory perception, thus hampering the search for sustainable alternatives.
Here, we show that the dripping-onto-substrate (DoS) rheometry protocols we developed enable the characterization of extensional rheology of the polymer solutions and multicomponent formulations. We investigate the influence of polysaccharide thickeners on the rheology and fizzics of plant-based milk emulsions, real and vegan mayo, and model paints and cosmetics. We find that the pursuit of practically motivated problems concerning rheology, shelf-life, and consumer perception of sustainable formulations involves fundamental problems in soft matter physics and fluid mechanics. We probe the influence of ingredient-specific interactions and dynamics by elucidating the impact of significant stretching, unraveling, and orientation of polymers and proteins (or drop/bubble deformation and breakup) in response to nonlinear extensional flows. A deeper understanding of pinching dynamics and the governing mechanical quantities compels exploration and advances into the physics and mathematics of self-similarity, finite-time singularity, coalescence and spreading kinetics, stretched polymer physics, and scaling or dimensional analysis.
Bio
Vivek Sharma, Ph.D.
Associate Professor, Chemical Engineering
University of Illinois Chicago
Dr. Vivek Sharma is an Associate Professor of Chemical Engineering at the University of Illinois Chicago (UIC). His Soft Matter ODES-lab (optics, dynamics, elasticity, and self-assembly laboratory) develops distinctive experiments and theories to analyze interfacial and nonlinear flows, colloidal and surface forces, optics, shear and extensional rheology, and the processability of industrial and biological soft matter. His research program exploits and advances surfactant, proteins, & polymer physics, fizzics (the science of drops, bubbles, jets, foams, and emulsions), and fluid mechanics to facilitate macromolecular engineering of formulations, including coatings, fibers, cosmetics, and plant-based foods. Vivek also publishes as a poet, an essayist, and a translator.
Vivek received a B. Tech (Textile) from IIT Delhi and an M. S. (Polymer Science, 2003) from the University of Akron. He obtained his M. S. (Chemical Engineering, 2006) and Ph. D. (Polymers/MSE, 2008) from Georgia Tech. Following post-doctoral research in Mechanical Engineering at MIT, he established ODES-lab at UIC in November 2012. Vivek was selected as the Distinguished Young Rheologist by TA Instruments in 2015 and won the 3M Non-Tenured Faculty Award in 2019. At UIC, he received the College of Engineering (COE) Teaching Award in 2017 & 2023 and the COE Advising Award in 2022. Vivek is the winner of the 2023 John H. Dillon Medal awarded by the American Physical Society.