Kenneth S Schweizer
- Morris Professor of Materials Science and Engineering
Develops and applies statistical mechanical theories to understand equilibrium and dynamical phenomena in soft materials, e.g. colloids, polymers, and liquid crystals.
- Ph.D., Physics - University of Illinois, Urbana-Champaign - 1981
- M.S., Physics - University of Illinois, Urbana-Champaign - 1976
- B.S. (summa cum laude), Physics - Drexel University - 1975
- Macromolecular, Colloidal and Complex Fluid Theory
Macromolecular, Colloidal, and Complex Fluid Theory
Our overarching goal is the development and application of novel molecular-scale statistical mechanical theories of the equilibrium and dynamic properties of polymers, colloids, nanoparticles, liquid crystals, elastomers, nanocomposites and other complex fluids and soft materials. A common theme is to both understand existing systems at a fundamental level and develop predictive methods for guiding the experimental design of new materials. Five broad areas are of present interest.
The uniquely slow dynamics and elasticity of entangled polymer liquids is a fascinating scientific problem of high engineering and processing importance. Existing theoretical approaches are phenomenological. We are developing first principles statistical mechanical theories that explicitly capture the dynamical consequences of polymer connectivity and uncrossability for diverse macromolecular architectures (rigid rods, flexible chains, star-branched objects) in solution, melts, thin films and liquid crystalline states. Molecular level theories of the rheology of these systems under both constant constant stress and strain rate conditions are also being developed. The work is relevant not only to synthetic polymeric materials, but also dense collections of stiff biopolymers commonly found in cell biology and crucial for the mechanical function of the cytoskeleton.
"Particle-polymer" mixtures, in solution and melt states, are ubiquitous in diverse areas of science and technology. We have developed predictive theories of the equilibrium structure, properties and phase behavior of such polymer nanocomposites based on integral equation methods. Present work is focused on dense nanocomposites involving functional particles such as buckeyballs, or fillers that are soft and fluctuating such as crosslinked nanogels. We are building on our advances in predicting equilibrium structure to tackle the complex problem of the dynamics and mechanical response of these hybrid materials. Questions such as how fast do nanoparticles diffuse and hop in a polymer liquid or network, can nanoparticles gel or jam in the polymer matrix, how do particles modify polymer entanglements, elasticity (reinforcement) and viscosity, and the role of particle size, shape, interactions with the polymer, and nanocomposite statistical microstructure are being investigated.
A broad area of enduring interest is the slow dynamics of glass-forming fluids. We are developing molecular-level theories of relaxation, diffusion, viscoelasticity and vitrification of deeply supercooled liquids including molecular, polymer, metallic and colloidal and nanoparticle systems. New ideas about the origin of dynamic cooperativity and rare collective activated events have been conceived and are being quantitatively applied to experimental materials. This advance provides a foundation for treating polymer thin films which are of high engineering importance. A major aim is to understand the remarkably large speed up of dynamics observed when polymer films are thinner than 30-50 nanometers and have at least one surface exposed to air.
The development of functional colloidal assemblies in solution is of high interest. We are developing microscopic statistical mechanical theories of the self-assembly of patchy Janus colloids, the coupled translation-rotation dynamics, vitrification, and gelation of dense suspensions of nonspherical particles, electron conductivity in metallic nanoparticle gels, and how colloids organize and move in large mesh polymer networks. These topics connect with our efforts in the interdisciplinary area of basic energy sciences.
A new direction is to understand gas and molecule permeability in polymeric materials in the molten, crosslinked rubber, and glass states. This requires treating the effect of penetrant size, shape and interactions with the polymer on solubility, and the role of length scale dependent polymer dynamics and free volume on penetrant diffusion. A major goal is to establish molecular-level design rules for both optimizing permeability for membrane-based separation applications, and minimizing permeability to fabricate new barrier materials that protect polymers from degradation processes. In addition, the effect of nonequilibrium physical aging and external stress on these phenomena is of interest. This research also underpins the development of high performance “self-healing” materials where controlling the transport of small molecules and oligomers in polymeric microcapsules is essential.
Selected Articles in Journals
- D.M. Sussman, K.S. Schweizer, Space-time Correlated Two-particle Hopping in Glassy Fluids: Structural Relaxation, Irreversibility, Decoupling, and Facilitation, Physical Review E 5, 061504 (2012).
- D.M.Sussman and K.S.Schweizer, Microscopic Theory of the Dynamics of Quiescent and Deformed Topologically Entangled Rod Solutions: General Formulation and Nonlinear Stress Relaxation, Macromolecules, 45, 3270 (2012).
- D.M. Sussman and K.S. Schweizer, Communication: Effects of Stress on the Tube Confinement Potential and Dynamics of Topologically Entangled Rod Fluids, Journal of Chemical Physics, 135, 131104, (2011).
- R. Jadrich and K.S. Schweizer, Percolation, Phase Separation, and Gelation in Fluids and Mixtures of Spheres and Rods, J. Chemical Physics, 135, 234902, (2011).
- U. Yamamoto and K.S. Schweizer, Theory of Nanoparticle Diffusion in Unentangled and Entangled Polymer Melts, J. Chemical Physics, 135, 224902, (2011).
- S.Y. Kim, K.S. Schweizer and C.F. Zukoski, Multiscale Structure, Interfacial Cohesion, Adsorbed Layers, and Thermodynamics in Dense Polymer-Nanoparticle Mixtures, Physical Review Letters, 107, 225504, (2011).
- D.M. Sussman and K.S. Schweizer, Microscopic Theory of the Tube Confinement Potential for Liquids of Topologically Entangled Rigid Macromolecules, Physical Review Letters, 107, 078102, (2011).
- R. Zhang and K.S. Schweizer, Kinetic Arrest, Dynamical Transitions and Activated Relaxation in Dense Fluids of Attractive Nonspherical Colloids, Phys. Rev. E-Rapid Commun., 83, 060502(R) (2011).
- D.M. Sussman and K.S. Schweizer, Microscopic Theory of Topologically Entangled Fluids of Rigid Acromolecules, Physical Review E, 83, 061501, (2011).
- K. Chen and K.S. Schweizer, Theory of Yielding, Strain Softening & Steady Plastic Flow in Polymer Glasses Under Constant Rate Deformation, Macromolecules, 44, 3988-4000 (2011).
- J. Yang and K.S. Schweizer, Glassy Dynamics and Mechanical Response in Dense Fluids of Soft Repulsive Spheres. II. Shear Elasticity, Connections Between Relaxation and Mechanical Response, and Nonlinear Rheology, J. Chem. Phys., 134, 204909 (2011).
- J.Yang and K.S.Schweizer, Glassy Dynamics and Mechanical Response in Dense Fluids of Soft Repulsive Spheres. I. Activated Relaxation, Kinetic Vitrification and Fragility, Journal of Chemical Physics, 134, 204908 (2011).
- R. Chakrabarti, J.-Y. Delannoy, M. Couty and K.S. Schweizer, Packing Correlations, Collective Scattering and Compressibility of Fractal-like Aggregates in Polymer Nanocomposites and Suspensions, Soft Matter, 7, 5397 (2011).
- L.M. Hall and K.S. Schweizer, Impact of Monomer Sequence, Composition and Chemical Heterogeneity on Copolymer-Mediated Effective Interactions between Nanoparticles in Melts, Macromolecules, 44(8), 3149-3160 (2011).
- M. Tripathy and K.S. Schweizer, Activated Dynamics in Dense Fluids of Attractive Nonspherical Particles. II. Elasticity, Barriers, Relaxation, Fragility and Self-Diffusion, Physical Review E, 83, 041407, (2011).
- M. Tripathy and K.S. Schweizer, Activated Dynamics in Dense Fluids of Attractive Nonspherical Particles. I. Kinetic Crossover, Dynamic Free Energies, and the Physical Nature of Glasses and Gels, Physical Review E, 83, 041406 (2011)
- D.M. Sussman and K.S. Schweizer, Theory of Two-Particle Correlated Activated Glassy Dynamics: General Formulation and Heterogeneous Structural Relaxation in Hard Sphere Fluids, J. Chemical Physics, 134, 064516 (2011).
- S.Y. Kim, L.M. Hall, K.S. Schweizer and C.F. Zukoski, Long Wavelength Concentration Flucutations and Cage Scale Ordering of Nanoparticles in Concentrated Polymer Solutions, Macromolecules, 43, 10123-10131 (2010).
- R. Chakrabarti and K.S. Schweizer, Polymer-mediated Spatial Organization of Nanoparticles in Dense Melts: Transferability and an Effective One-component Approach, Journal of Chemical Physics, 133, 144905 (2010).
- R.C. Kramb, R. Zhang, K.S. Schweizer and C.F. Zukoski, Re-entrant Kinetic Arrest and Elasticity of Concentrated Suspensions of Spherical and Nonspherical Repulsive and Attractive Colloids, Journal of Chemical Physics, 134, 014503 (2011).
- K. Chen and K.S. Schweizer, Theory of Aging, Rejuvenation, and the Nonequilibrium Steady State in Deformed Polymer Glasses, Physical Review E, 82, 041804 (2010).
- R. Zhang and K.S. Schweizer, Dynamic Free Energies, Cage Escape Trajectories, and Glassy Relaxation in Dense Fluids of Uniaxial Hard Particles, J. Chemical Physics, 133, 104902 (2010).
- R.C. Kramb, R. Zhang, K.S. Schweizer and C.F. Zukoski, Glass Formation and Shear Elasticity in Dense Suspensions of Nonspherical Repulsive Particles, Physical Review Letters, 105, 055702 (2010).
- K. Chen, E.J. Saltzman and K.S. Schweizer, Molecular Theories of Segmental Dynamics and Mechanical Response in Deeply Supercooled Polymer Melts and Glasses, Annual Reviews of Condensed Matter Physics, 1, 277 (2010). (Invited)
- J. Yang and K.S. Schweizer, Tunable Dynamic Fragility, Shear Elasticity and Soft Jamming in Dense Suspensions of Many Arm Star Polymer Colloids, Europhysics Letters, 90, 66001 (2010).
- B. Wang, J. Guan, S.M. Anthony, S.C. Bae, K.S. Schweizer and S. Granick, Confining Potential when a Biopolymer Reptates, Phys.Rev.Lett., 104, 118301 (2010).
- L.M.Hall, A.Jayaraman and K.S.Schweizer, Molecular Theories of Polymer Nanocomposites, Current Opinion in Solid State and Materials Science 14, 38 (2010). (Invited)
- M.Tripathy and K.S.Schweizer, The Influence of Shape on the Glassy Dynamics of Hard Nonspherical Particle Fluids I. Dynamic Crossover and Elasticity, J.Chemical Physics, 130, 244906 (2009).
- K.Chen and K.S.Schweizer, Suppressed Segmental Relaxation as the Origin of Strain Hardening in Polymer Glasses, Physical Review Letters, 102, 038301(2009).
- A.Jayaraman and K.S.Schweizer, Effective Interactions, Structure and Phase Behavior of Lightly Tethered Nanoparticles in Polymer Melts, Macromolecules, 41, 9430 (2008).
- K.Chen and K.S.Schweizer, Microscopic Constitutive Equation Theory for the Nonlinear Mechanical Response of Polymer Glasses, Macromolecules, 41, 5908 (2008).
- L. Hall and K.S.Schweizer, Many Body Effects on the Structure and Miscibility of Polymer Nanocomposites, J. Chemical Physics, 128, 234901 (2008).
- E.J.Saltzman and K.S.Schweizer, Large Amplitude Jumps and Nongaussian Dynamics in Glassy Hard Sphere Fluids, Physical Review E, 77, 051504 (2008).
- D.Viehman and K.S.Schweizer, Theory of Gelation, Vitrfication and Activated Barrier Hopping in Mixtures of Hard and Sticky Spheres, J.Chemical Physics, 128, 084509 (2008).
- William L. Everitt Award for Teaching Excellence, COE, UIUC (2002)
- Burnett Award for Undergraduate Teaching Excellence (1997)
- Joel Henry Hildebrand Award in the Theoretical and Experimental Chemistry of Liquids, American Chemical Society (2016)
- Polymer Physics Prize, American Physical Society (2008)
- Tau Beta Pi Daniel P. Drucker Eminent Faculty Award, COE, UIUC (2008)
- G. Ronald and Margaret H. Morris Endowed Professorship of Materials Science and Engineering, UIUC/MatSE (2001)
- DOE-BES Award for Outstanding Scientific Achievement in Materials Chemistry (1996)
- Fellow, American Physical Society (1996)
- R&D100 Award for Technologically Significant Innovation (1992)
- John H. Dillon Medal, American Physical Society (1991)
- Sandia National Laboratories Award for Excellence in Research (1990)