Michael J. Solomon
Professor, Dean and Vice-Provost for Academic Affairs – Graduate Studies, Rackham Graduate School
2800 Plymouth Road, Ann Arbor, MI 48109-2800
University of California at Berkeley
PhD ChE ’96
University of Wisconsin at Madison
BS ChE and Economics ’90
Our research investigates complex fluids and soft matter – soft materials with properties intermediate between fluids and solids. Our current interests include self-assembly of colloids, colloidal gelation, active matter, and the biomechanics of bacterial biofilms. Applications that interest us include creating new optical materials, sensors, biomedical devices and procedures, as well as materials for energy management. The potential to create new materials that reconfigure autonomously – and in response to environmental stimuli – is of particular interest to us.
The assembly of colloids into useful structures has long been a key aim of chemical engineers and materials scientists. For example, ordered arrays of colloidal particles formed in the liquid state can be further processed to yield iridescent, structural color materials useful for sensing, optical materials, and control of the electromagnetic response of materials. There structures could be reconfigured to manipulate loads, as needed for microrobotic applications. Yet, the success of this technological aim is severely hindered by some deep fundamental problems. For example, the crystal structures that have been fabricated to date are disappointingly small, most likely because typical colloidal building blocks are not nearly complex as molecules. Structures are also quite defect prone. We address this challenge by synthesizing colloids—often anisotropic—and assembling them with the assistance of applied electric fields. In a second effort, we address the fact that the typical size of the ordered arrays that have been produced in academia is currently too small for real-world applications. These questions are studied within a collaborative, student-driven research program that includes novel colloid synthesis, direct visualization of assembly structure and dynamics by confocal microscopy, functional property characterization by light scattering and reflectivity measurements, and rheological measurements. This research is supported by DOE and involves collaboration with Professor Sharon Glotzer.
Colloidal gelation and active matter
Colloidal gelation is a common industrial process to manage the rheological and microstructural properties of complex fluid formulations used in the stabilization of consumer products, ceramic materials and pharmaceutical formulations. By developing new 3D confocal microscopy methods, our group has made fundamental discoveries about gels that are currently being applied in industry to develop new materials and complex fluid processing methods. Currently, we are engaged in investigation of the thixotropic response of gels in collaboration with Professor Ron Larson. A new direction of this work is to incorporate active matter into colloidal gels. By incorporating colloids with driven dynamics, we control and exploit the microrheological response of colloidal gels for technological applications. It is also a rich avenue for the scientific investigation of the interaction of active matter with passive colloids. This work involves a combination of advanced microscopy techniques, flow cell fabrication using methods such as microfabrication, and rheological measurements. This research is supported by NSF and Procter & Gamble.
Biomechanics of bacterial biofilms
With Dr. Scott vanEpps of the University of Michigan Department of Emergency Medicine, we are exploring the biomechanical properties of bacterial biofilms. Biofilms are colonies of microorganisms that are pervasive in a range of natural and industrial settings. They can also grow on devices, such as intravascular catheters, that are introduced into the body as part of medical practice. Biofilm structure and mechanics is thought to play a protective role by, for example, improving the resistance of bacteria to antibiotic treatments. The aim of this project is to understand and measure the mechanical properties of biofilms and understand physical variables that might be able to control and resolve their infection in medical devices. We are in particular engaged in exploiting heat effects on biofilm viability and structure as a control mechanism. We are also investigating the fundamental science of biofilm and host interactions. We also engaged in studies of the polymer science of the extracellular polysaccharides and other polysaccharide polymers, rheological characterization of whole biofilms, and confocal microscopy visualization of the complex microscopic structure of biofilms. This research is supported by NIH.
Michael Solomon is professor of chemical engineering, professor of macromolecular science and engineering, dean of Rackham Graduate School, and vice provost for academic affairs – graduate studies at the University of Michigan. He was previously Dow Corning assistant professor of chemical engineering and has been member of the Michigan faculty since 1997. Prior to joining Michigan, Mike was a post-doctoral research fellow at the University of Melbourne, Australia. He received his B.S. in chemical engineering and economics from the University of Wisconsin at Madison in 1990 and his Ph.D. in chemical engineering from the University of California at Berkeley in 1996. He was a Rotary Foundation International Fellow in economics at the Université d’Aix-Marseille II, Aix-en-Provence, France from 1990-1991.
Solomon’s research interests are in the area of complex fluids and soft matter – soft materials with properties intermediate between fluids and solids. He and his group have been recongnized for their application of confocal microscopy direct visualization tools to understand the assembly and function of soft matter, including the yielding of colloidal gels, the self-assembly of anisotropic colloids, field-assisted colloidal crystallization, and the microrheology of bacterial biofilms.
His teaching interests have included development of undergraduate courses in polymer science and engineering, molecular engineering, and chemical engineering process economics as well as graduate electives in nano and colloidal assembly and light scattering. Mike has received the College of Engineering 1938E Award (2002), the University of Michigan Russel Award (2003), the U-M ASEE Outstanding Professor of the Year Award (2006), the University of Michigan’s Faculty Recognition Award (2008) and the COE Education Excellence Award (2010). He has been recipient of the NSF CAREER award, 3M’s non-Tenured Faculty award, and the 2011 Soft Matter Lectureship from the Royal Society of Chemistry’s journal Soft Matter. He is fellow of the American Association for the Advancement of Science and the American Physical Society.
Solomon previously chaired the Society of Rheology’s Education Committee and its Metzner Award Committee as well as the Fluid Mechanics Programming Committee of the American Institute of Chemical Engineers. He is currently member of the Editorial Advisory Board of the Journal Rheologica Acta and past Editorial Board member of Langmuir. From 2012 – 2017 he was Associate Dean for Academic Programs and Initiatives at the Horace H. Rackham School of Graduate Studies. He was named dean of Rackham Graduate School and vice provost for academic affairs – graduate studies in July 2018.
Solomon has taught the junior-level separation course (ChE 343), for which he wrote a course pack. Previous electives Professor Solomon has offered are Polymer Science and Engineering (ChE 472), Molecular Engineering (ChE 496, with Mark Burns), Scattering and Optical Methods for Complex Fluids (ChE 696) as well as Nano and Colloidal Assembly (ChE 696). He also created the department’s new one-credit course in ChE process economics (ChE 485). Previously, Solomon taught the introductory material and energy balance course (ChE 230), undergraduate fluid mechanics (ChE 341), the junior chemical engineering laboratory (ChE 360) and graduate fluid dynamics (ChE 527).
Ferrar, J.A., D.S. Bedi, S. Zhou, P. Zhu, X. Mao, and M.J. Solomon,” Capillary-driven binding of thin triangular prisms at fluid interfaces,” Soft Matter, 14 3902-3918 (2018), DOI: 10.1039/C8SM00271A.
Solomon, M.J., “Tools and Functions of Reconfigurable Colloidal Assembly,” Langmuir (2018); DOI: 10.1021/acs.langmuir.7b03748.
Wei, Y., M.J. Solomon, and R.G. Larson, “A Multi-Mode Structural Kinetics Constitutive Equation for the Transient Rheology of Thixotropic Elasto-viscoplastic Fluids,” Journal of Rheology 62 (2018) DOI: 10.1122/1.4996752.
Ferrar, J.A., L. Pavlovsky, Y. Liu, E. Viges, and M.J. Solomon, “Two-step continuous production of monodisperse colloidal ellipsoids at rates of one gram per day,” AIChE Journal 64(2) 697-707 (2018); DOI:10.1002/aic.16009.
Adams, A., X. Xia, M.J. Solomon, and R.G. Larson, “Concentration, salt and temperature dependence of strain hardening of step shear in CTAB/NaSal surfactant solutions,” Journal of Rheology 61, 967–977 (2017). doi:10.1122/1.4996008 .
Hsiao, L.C., I. Saha-Dalal, R.G. Larson, Solomon, M.J., “Translational and rotational dynamics in dense suspensions of smooth and rough colloids,” Soft Matter 13(48) 9229-9236 (2017). DOI: 10.1039/c7sm02115a.
Ma, T.M., J.S. vanEpps, M.J. Solomon, “Structure, Mechanics, and Instability of Fibrin Clot Infected with Staphylococcus epidermidis,” Biophysical Journal 113(9) 2100-2109 (2017). DOI: http://dx.doi.org/10.1016/j.bpj.2017.09.001 .
Silvera Batista, C., H. Rezvantalab, R.G. Larson, and M.J. Solomon, “Controlled Levitation of Colloids through Direct Current Electric Fields,” Langmuir 33 (41), 10861–10867 (2017). DOI: 10.1021/acs.langmuir.7b00835.
Hsiao, L. C., Jamali, S., Glynos, E., Green, P. F., Larson, R. G., and Solomon, M. J. “Rheological State Diagrams for Rough Colloids in Shear Flow,” Physical Review Letters 119, no. 15 (2017): 158001. doi:10.1103/PhysRevLett.119.158001.
Szakasits, M.E., W. Zhang, and M.J. Solomon, “Dynamics of fractal cluster gels with embedded active colloids,” Physical Review Letters 119, 58001 (2017). doi:10.1103/PhysRevLett.119.058001 .
Ganesan, M. and M.J. Solomon, “High-density Equilibrium Phases of Colloidal Ellipsoids by Application of Optically Enhanced, Direct Current Electric Fields,” Soft Matter 6, 557–562 (2017). doi:10.1039/C7SM00359E.
Stewart, E.J., D.E. Payne, B.R. Boles, J.G. Younger, M.J. Solomon, “Effect of antimicrobial and physical treatments on growth of multispecies staphylococcal biofilms,” Applied and Environmental Microbiology, (2017) doi: 10.1128/AEM.03483-16.
Wei, Y., M.J. Solomon, and R.G. Larson, “Quantitative nonlinear thixotropic model with stretched exponential relaxation in transient shear flows,” Journal of Rheology, 60 1301-1315 (2016). DOI: 10.1122/1.4965228.
Ganesan, M., S. Knier, J.G. Younger, and M.J. Solomon, “Associative and entanglement contributions to the solution rheology of a bacterial polysaccharide,” Macromolecules 49(21) 8313-8321 (2016). DOI: 10.1021/acs.macromol.6b01598.
McCarroll, L., M.J. Solomon, and W. Schultz, “Differential analysis of capillary break-up rheometry for Newtonian liquids,” J. Fluid Mechanics 804 116-129 (2016). DOI: http://dx.doi.org.proxy.lib.umich.edu/10.1017/jfm.2016.531.
Kim, Y, A. Adams, W.H. Hartt, R.G. Larson, and M.J. Solomon, “Transient, near-wall shear-band dynamics in channel flow of wormlike micelle solutions,” J. Non-Newtonian Fluid Mechanics 232 77-87 (2016). DOI: 10.1016/j.jnnfm.2016.03.009.
Stotsky, Jay A., Jason F. Hammond, Leonid Pavlovsky, Elizabeth J. Stewart, John G. Younger, Michael J. Solomon, and David M. Bortz. “Variable Viscosity and Density Biofilm Simulations Using an Immersed Boundary Method, Part II: Experimental Validation and the Heterogeneous Rheology-IBM.” Journal of Computational Physics 316: 204–22 (2016). doi:10.1016/j.jcp.2016.04.027.
Beltran-Villegas, D., Colón-Meléndez, L., M.J. Solomon, and R.G. Larson, “Kinetic modeling and design of colloidal lock and key assembly,” J. Colloid Interface Science 463 242-257 (2016). DOI: 10.1016/j.jcis.2015.10.062.
Richardson, I.P., R. Sturtevant, M. Heung, M.J. Solomon, J.G. Younger, and J. Scott VanEpps, “Hemodialysis Catheter Heat Transfer for Biofilm Prevention and Treatment,” ASAIO Journal 62(1) 92-9 (2016). doi: 10.1097/MAT.0000000000000300. PMID: 26501916.
Schwartz, K., M. Ganesan, D.E. Payne, M.J. Brown, M.J. Solomon, B.R. Boles, “Extracellular DNA facilitates the formation of functional amyloids in Staphylococcus aureus biofilms,” Molecular Microbiology 99(1) 123-134 (2016). DOI: 10.1111/mmi.13219.
Rahami, S., C.H. Villa, A.F. Dishman, M.E. Grabowski, D. Pan, H. Durmaz, A.C Misra, L. Colón-Meléndez, M.J. Solomon, V.R. Muzykantov, and J. Lahann, “Long-circulating Janus nanoparticles made by electrohydrodynamic co-jetting for systemic drug delivery applications,” Journal of Drug Targeting 23 750-758 (2015). DOI: 10.3109/1061186X.2015.1076428.
Hsiao, L.C., B.A. Schultz, J. Glaser, M. Engel, M.E. Szakasits, S.C. Glotzer, M.J. Solomon, “Metastable orientational order of colloidal discoids,” Nature Communications, 6:8507 (2015). doi: 10.1038/ncomms9507.
Stewart, E.J., M. Ganesan, J.G. Younger, and M.J. Solomon, “Artificial biofilms establish the role of matrix interactions in staphylococcal biofilm assembly and disassembly,” Scientific Reports, 5, 13081 (2015); doi: 10.1038/srep13081. PMID: 26272750.
Sturtevant, R.A., P. Sharma, L. Pavlovsky, E.J. Stewart, M.J. Solomon, J.G. Younger, “Thermal Augmentation of Vancomycin against Staphylococcal Biofilms,” Shock, 44(2), 121-127 (2015); doi: 10.1097/SHK.0000000000000369. PMID: 25784524.
Colón-Meléndez, L., D. Beltran-Villegas, J. Liu, M. Spellings, S. Sacanna, D. Pine, S.C. Glotzer, R.G. Larson and M.J. Solomon, “Measuring and predicting rate constants for colloidal particle lock-and-key binding,” Journal of Chemical Physics 142(17) 174909 (2015). DOI: 10.1063/1.4919299.
Ferrar, J.A. and M.J. Solomon, “Kinetics of colloidal deposition, assembly, and crystallization in steady electric fields,” Soft Matter, 11, 3599 – 3611 (2015). DOI: 10.1039/C4SM02893G.
Pavlovsky, L., R. Sturtevant, J.G. Younger, and M.J. Solomon, “Effects of Temperature on the Morphological, Polymeric, and Mechanical Properties of Staphylococcus epidermidis Bacterial Biofilms,” Langmuir 31(6) 2036-2042 (2015). DOI: 10.1021/la5044156. PMID: 25602470.
Shah, A.A. B. Schultz, W. Zhang, S.C. Glotzer, and M.J. Solomon, “Actuation of shape-memory colloidal fibres of Janus ellipsoids,” Nature Materials 14 117-124 (2015) DOI: 10.1038/nmat4111.
Shemi, O. and M.J. Solomon, “Effect of surface chemistry and metallic layer thickness on the clustering of metallodielectric Janus spheres,” Langmuir 30(51) 15408-15415 (2014). DOI: 10.1021/la503486p.
Hsiao, L.C., H. Kang, K.H. Ahn, and M.J. Solomon, “Role of shear-induced dynamical heterogeneity in the non-linear rheology of colloidal gels,” Soft Matter 10(46) 9254-9259 DOI: 10.1039/C4SM01375A (2014).
Pavlovsky, L., M. Ganesan, J.G. Younger, and M.J. Solomon, “Elasticity of microscale volumes of viscoelastic soft matter by cavitation rheology,” Applied Physics Letters 105, 114105 (2014); DOI: 10.1063/1.4896108. PMID: 25316925.
Shah, A.A., M. Ganesan, J. Jocz, and M.J. Solomon, “Direct Current Electric Field Assembly of Colloidal Crystals Displaying Reversible Structural Color,” ACS Nano 8(8), 8095–8103 (2014). DOI: 10.1021/nn502107a.
Hsiao, L.C., K.A. Whitaker, M.J. Solomon, and E.M. Furst, “A model colloidal gel for coordinated measurements of force, structure, and rheology,” 58 1485-1504, J. Rheology (2014). DOI: 10.1122/1.4884965.
Hammond, J.F., E.J. Stewart, J.G. Younger, M.J. Solomon, and D.M. Bortz, “Variable Viscosity and Density Biofilm Simulations using an Immersed Boundary Method, Part I: Numerical Scheme and Convergence Results,” Computer Modeling in Engineering and Sciences 1(1) 1-47 (2014). DOI: 10.3970/cmes.2014.098.295.
Kim, Y, A.A. Shah, and M.J. Solomon, “Spatially and temporally reconfigurable assembly of colloidal crystals,” Nature Communications, 5:3676 DOI: 10.1038/ncomms4676 (2014).
For a complete list of publications, please cf. Mike Solomon’s cv.