University of California at Berkeley
PhD CHE ’96
University of Wisconsin at Madison
BS CHE and Economics ’90
Our research investigates complex fluids – soft materials with properties intermediate between fluids and solids. Our current interests include nanocolloidal assembly, colloidal gelation, 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 assembly of nanocolloids 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 photonic crystal structures useful for sensing and optical materials. 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 nanocolloidal building blocks are not nearly complex as molecules. We address this challenge by synthesizing anisotropic colloids and assembling them with the assistance of applied electric, shear and gravitational fields. We collaborate with Profs. Sharon Glotzer, Mark Burns and Joanna Millunchick in pursuit of this aim. 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. In collaboration with Professor Ron Larson, we have investigated the complex fluid dynamics of large-scale methods for colloidal crystal production, such as spin coating. These questions are studied within a collaborative, student-drive research program that includes novel colloid synthesis, direct visualization of assembly structure and dynamics by confocal microscopy as well as rheological measurements.
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 an investigation of the origin of rupture and yielding in colloidal gels. The work involves a combination of advanced microscopy techniques, flow cell fabrication using methods such as microfabrication, and rheological measurements.
Biomechanics of bacterial biofilms
With Dr. John Younger of the U-Michigan Department of Emergency Medicine and collaborators at two other universities, 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 of size about 10 – 100 microns, since these dimensions match the scales relevant to medical practice. As part of this work, we have developed a flexible microfluidic rheometer for micromechanical measurements of bacterial biofilm elasticity. Current work is focused on molecular characterization of the extracellular polysaccharides present in biofilms, rheological characterization of whole biofilms, and confocal microscopy visualization of the complex microscopic structure of biofilms.
Our research is supported by NSF, NIH, DOE, and Procter & Gamble.
Michael Solomon is Professor of Chemical Engineering and Professor of Macromolecular Science and Engineering 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 U-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 – soft materials with properties intermediate between fluids and solids. His group has developed and applied 3D confocal microscopy methods to study the soft matter phenomena of self-assembly, gelation, and the biomechanics of bacterial biofilms. His work has also included discovery of a universal scaling for polymer scission in turbulence that identifies the limits that scission imposes on turbulent drag reduction. Other research interests have included the rheology of polymer nanocomposites, the microrheology of complex fluids and the microfluidic synthesis of anisotropic particles.
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 Rackham Graduate School’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.
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 current member of the Editorial Advisory Board of the Journal Rheologica Acta. Currently, Solomon is Associate Dean for Academic Programs and Initiatives at the Horace H. Rackham School of Graduate Studies at the University of Michigan.
Most recently, Solomon has taught the junior-level separation course (ChE 343), for which he wrote a course pack, and Chemical Engineering Process Economics (ChE 485). 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).
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, accepted for publication (2015).
Stewart, E.J., M. Ganesan, J.G. Younger, and M.J. Solomon, “Bacterial constructs with biofilm-like properties by physical self-assembly of cellular and polymeric constituents,” 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. Published online 10 November 2014.
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).
Stewart, E.J., A. Satorius, J.G. Younger, and M.J. Solomon, “Role of environmental and antibiotic stress on Staphylococcus epidermidis biofilm microstructure,” Langmuir. 29(23) 7017-7024 (2013). PMID: 23688391.
Ganesan, M., E.J. Stewart, J. Szafranksi, A.E. Satorius, J.G. Younger, and M.J. Solomon, “Molar mass, entanglement, and associations of the biofilm polysaccharide of Staphylococcus epidermidis,” Biomacromolecules, 14 1474-1481 (2013). PMID: 23540609.
Satorius AE, Szafranski J, Pyne D, Ganesan M, Solomon MJ, Newton DW, Bortz DM, Younger JG. “Complement c5a generation by staphylococcal biofilms,” Shock 39(4) 336-342 (2013). PMID: 23459111.
Shah, A, B. Schultz, K.L. Kohlstedt, S.C. Glotzer, and M.J. Solomon, “Synthesis, Assembly, and Image Analysis of Spheroidal Patchy Particles,” Langmuir, 29 4688-4696 (2013).
Pavlovsky, L., J.G. Younger and M.J. Solomon. “In situ rheology of Staphylococcus epidermidis Bacterial Biofilms,” Soft Matter, 9(1) 122-131 (2013). PMID: 25544855.
Hsiao, L.C., R.S. Newman, S.C. Glotzer, and M.J. Solomon, “Role of isostaticity and load-bearing microstructure in the elasticity of yielded colloidal gels,” Proceedings of the National Academy of Sciences of the United States of America 109(40) 16029-16034 (2012).
Thornton, M., C. Irvin, H. M. Chung, D. M. Bortz, M. J. Solomon, & J. G. Younger., “Multicellularity and Antibiotic Resistance in Klebsiella pneumoniae Grown under Bloodstream-Mimicking Fluid Dynamic Conditions,” J. Infectious Diseases 206 588-595 (2012).
Shah, A., H. Kang, K. Kohlstedt, K-H Ahn, S.C. Glotzer, C.W. Monroe and M.J. Solomon, “Liquid crystal order in colloidal suspensions of ellipsoidal particles by direct current electric field assembly,” Small 8(10) 1551-1562 (2012).
Solomon, M.J., “Directions for targeted self-assembly of anisotropic colloids from statistical thermodynamics,” Current Opinion in Colloid Interface Science, 16 158-167 (2011).
Dzul, S.P., M.M. Thornton, D.N. Hohne, D.M. Bortz, M.J. Solomon and J.G. Younger, “Contribution of the Klebsiella pneumoniae Capsule to Bacterial Community Microstructure Determined With High-Resolution Confocal Microscopy,” Applied and Environmental Microbiology 77(5) 1777-1782 (2011).
Byrne, E., S. Dzul, M.J. Solomon, J. Younger and D.M. Bortz, “Postfragmentation density function for bacterial aggregates in laminar flow,” Phys. Rev E. 83 041911 (2011).
Mukhija, D. and M.J. Solomon, “Nematic order in suspensions of colloidal rods by application of a centrifugal field,” Soft Matter, 7 540-545 (2011).
Elbing, B., M.J. Solomon, M. Perlin, D. Dowling and S.L. Ceccio, “Degradation of Drag-Reducing Polymer Solutions within a High-Reynolds Number Turbulent Boundary Layer,” J. Fluid Mechanics 670 337-364 (2011).
Shereda, L.T., R.G. Larson, and M.J. Solomon, “Shear banding in crystallizing colloidal suspensions,” Korea-Australia Rheology Journal 22(4) 309-316 (2010).
Shereda, L.T., R.G. Larson, and M.J. Solomon, “Boundary-driven colloidal crystallization in simple shear flow,” Physical Review Letters, 105 228302 (2010).
Iacovella, C.R., R.E. Rogers, S.C. Glotzer and M.J. Solomon, “Pair interaction potentials of colloids by extrapolation of confocal microscopy measurements of collective structure,” J. Chem. Phys. 133 art no 164903 (2010).
Zeitoun, R., D. Chang, S. Langelier, J. Millunchick, M. J. Solomon and M.A. Burns, “Selective Arraying of Complex Particle and Cell Pattern,” Lab on a Chip 10 1142-1147 (2010).
Solomon, M.J., “Reconfigurable colloids,” Nature 464 496-498 (2010).
Solomon, M.J. and P.T. Spicer, “Microstructural regimes of colloidal rod suspensions, gels, and glasses,” Soft Matter, 6 1391-1400 (2010).
Solomon, M.J. R. Zeitoun, D. Ortiz, K.E. Sung, A. Shah, M.A. Burns, S.C. Glotzer, J.M. Millunchick, “Toward assembly of open colloidal structures from anisotropic pentamer particles,” Macromolecular Rapid Communications 31 196-201 (2010).
Kogan, M and M.J. Solomon, “Electric-field induced yielding of colloidal gels in microfluidic capillaries,” Langmuir, 26(2) 1207-1213 (2010).