Michael J. Solomon

Michael J. Solomon

University of Michigan

Chemical Engineer
Fellow, Elected 2022

Michael J. Solomon has contributed to rheology through discoveries about the rheological and micromechanical properties of gels and biofilms; development of rheological methods that combine visualization and deformation; and service to the society and discipline. Solomon has generated new knowledge in rheology through his research group’s discovery of the micromechanical origins of colloidal gel rheology. Colloidal gels are commonly incorporated into materials in the consumer products, agricultural, and pharmaceutical industries because their elasticity and yield stress serve to stabilize material formulations. By novel application of confocal microscopy imaging he addressed the question of how colloidal gels yield upon shear deformation by observing the microscopic location of bond rupture events. He discovered that a set of highly connected (“rigid”) particles survive the deformation and determine the remnant mechanical properties of the yielded gel. Further discoveries have included the role anisotropy and backbone rupture in determining colloidal gel yielding and the generation of anisotropic microstructure during the steady flow of gels. He and his co-workers created active colloidal gels – materials comprised of active particles embedded in colloidal gels. They demonstrated how active particles modulate rheology in unexpected, amplified ways. Finally, he has pursued research that established how bacterial biofilm rheology is mediated by the physical chemical properties of microbial cells, their secreted extra-polymeric substances, and the interactions between these two biofilm components. This connection offers the possibility of using physical variables such as temperature, ionic strength, and pH as variables which can control biofilm proliferation and persistence on surfaces, as applicable to human health, environment, and water systems.

These fundamental discoveries in rheology were facilitated by the development of experimental methods which integrated viscometric flows with confocal microscopy direct visualization and with time-resolved small-angle light scattering. His research group also pioneered methods to measure the rheology of microbial biofilms by means of mechanical rheology, microfluidics, and microrheology.

Solomon has contributed to rheology through his service as Chair of The Society of Rheology Education Committee (2005-2010), during which the suite of short course offerings was expanded, and the Society moved to host multiple short courses during the annual meeting. He also served as a member of the Executive Committee during which the Society conducted strategic planning leading to the adoption of a mission statement. He was member and then chair of the Society’s newly established Financial Advisement Committee.

Mike received his Ph.D. in chemical engineering from the University of California at Berkeley in 1996. After a post-doctoral appointment at the University of Melbourne, Australia, he joined the faculty at the University of Michigan. He was 2011 recipient of the Soft Matter Lectureship, awarded by The Royal Society of Chemistry’s journal Soft Matter; he is an AAAS (2016) and APS Fellow (2017).

Based on the documents submitted by Ronald G. Larson.