Biographical Information

Family: wife Bebe and children Rachel, Emily, Andrew, and Eric

Education

Professional Experience

Recent Honors and Awards

Professional Service

Research Interests

Rheology and Flow of Complex Fluids. Many everyday substances are not readily classified as solids or liquids, but have flow properties (i.e., rheology) somewhere in between. Such fluids typically have a polymeric or colloidal microstructure much larger than the atomic which dominates the rheological (i.e., flow) properties. Through rheological experiments, theory, and computer simulations, our group is working out the relationship between the structure of these complex fluids and their rheology. Such knowledge is valuable in the optimal design of such fluids for applications in the polymer, pharmaceutical, and consumer products industries. Of particular interest at present are branched polymer melts, surfactant solutions, coating fluids, colloids, and biopolymers. We have current projects on the rheology of surfactant solutions, including those used in shampoos and body washes, and on the interfacial action of dispersants used in oil-spill clean up.  We also have a project to determine how best to control the rheology of latex coatings. We are developing advanced theories for the rheological properties of entangled polymers with long-chain branching.  We also helping design novel methods of high-speed manufacture of nanofibers, using rotary jet spinning.  The work includes experimental, theoretical, and computational components.

Molecular Simulations of Complex Fluids and Materials. Our group has multiple projects involving molecular simulations of polymers, surfactants, and colloids.  These include molecular dynamics simulations at the atomistic level, starting from interactions between atoms derived in part from ab initio (quantum mechanical) calculations, coarse-grained molecular dynamics simulations, Brownian dynamics simulations, Stochastic Rotation Dynamics, and Stokesian dynamics simulations.  We are specifically looking at polymers in strong flows, at levels of resolution ranging from atomistic simulations of short chains to Brownian dynamics simulations of very long chains.  This includes simple flows as well as flows of polymers through complex geometries, such as channels with contractions. We are also simulating self-assembling colloids, where anisotropic interactions between particles allow unique structures to self assemble and re-configure. We are carrying out atomistic and coarse-grained simulations of latex particle dispersions to better control their flow properties. We are simulating the interactions between drugs and cellulosic polymers used to optimize their release in the body.

Polyelectrolyte Interactions. We are studying the complexes formed by polymers of opposite charge, which are used to make layer-by-layer assemblies used for drug delivery or structured materials.  A special case is that of negatively charged DNA interacting with either positively charged proteins or positively charged nanoparticles.  In particular, we are examining the process by which such proteins find their target sites along double-stranded DNA molecules, using both single-molecule imaging methods, and theory.

Graduate Students:

Indranil Saha Dalal
Priyanka Desai
Wenjun Huang
Kyle Huston
Lei Jiang
Ali Salehi
Xueming Tang
Shi Yu
Fang Yuan
Weizhong Zou

Post-docs:

Daniel Beltran
Prateek Jha
Jun Liu
Mohammad Taghavi
Shihu Wang

Visiting Scholars:

Tongyang Zhao
Miqiu Kong

Other Relevant Homepages:

Mike Solomon Homepage
Mark Burns Homepage

Publications

Books

Structure and Rheology of Molten Polymers: From Structure to Flow Behavior and Back Again, Hanser Gardner (2006)
(Errata-PDF)

Constitutive Equations for Polymer Melts and Solutions , Out of Print, photocopied versions can be ordered by email for a $20 fee for photocopy expenses from Ron Larson at rlarson@engin.umich.edu
(Errata-PDF)

The Structure and Rheology of Complex Fluids , Oxford University Press (1999)
(Errata-PDF)

Recent Journal Publications

N. Watari and R.G. Larson, Phys. Rev. Lett. 102:246001 2009; “Shear-Induced Chiral Migration of Particles with Anisotropic Rigidity.

L.T. Shereda, R.G. Larson, and M.J. Solomon, Phys. Rev. Lett. 101:038301; "Local Stress Control of Spatiotemporal Ordering of Colloidal Crystals in Complex Flows."

Watari, M. Doi, and R.G. Larson, Phys. Rev. E, 78:011801 2008 "Fluidic trapping of deformable polymers in micro-flows."

Z.W. Wang and R.G. Larson Macromolecules 41:4945-4960 2008 "Constraint Release in Entangled Binary Blends of Linear Polymers: A Molecular Dynamics Study."

M.S. Rahman, R. Aggarwal, R.G. Larson, J.M. Dealy, and J. Mays, Macromolecules, 41:8225-8230 2008, "Synthesis and Dilute Solution Properties of Well-Defined H-Shaped Polybutadienes."

X. Chen, and R.G. Larson, Macromolecules 41:6871-6872 2008 "Effect of Branch Point Position on the Linear Rheology of Asymmetric Star Polymers."

Y. Heo, and R.G. Larson, Macromolecules, 41:8903-8915 2008, "Universal Scaling of Linear and Nonlinear Rheological Properties of Semi-Dilute and Concentrated Polymer Solutions."
S.L. Duncan, and R.G. Larson Biophys. J., 94:2965-2986, 2008 "Comparing Experimental and Simulated Pressure-Area Isotherms for DPPC."

L. Monticelli, S.K. Kandasamy, X. Periole, R.G. Larson, D.P. Tieleman, and S.J. Marrink, J. Chem. Theory and Computation, 4:819-834 2008 "The MARTINI Coarse-Grained Force Field: Extension to Proteins."

H. Lee and R.G. Larson, J. Phys. Chem. B 112:7778-7784 2008, "Coarse-Grained Molecular Dynamics Studies of the Concentration and Size Dependence of Fifth- and Seventh-Generation PAMAM Dendrimers on Pore Formation in DMPC Bilayer."

H. Lee and R.G. Larson, J. Phys. Chem. B 112:12279-12285 2008, "Lipid Bilayer Curvature and Pore Formation Induced by Charged Linear Polymers and Dendrimers: The Effect of Molecular Shape."

S.P. Holleran and R.G. Larson, Macromolecules 41:5042-5054 2008 "Multiple Regimes of Collision of an Electrophoretically Translating Polymer Chain Against a Thin Post."

S. Jain and R.G. Larson, Macromolecules 41:3692-3700 2008 "Effects of Bending and Torsional Potentials on High-Frequency Viscoelasticity of Dilute Polymer Solutions."

Courses Taught at the University of Michigan

Undergraduate ChE Courses

ChE 341 - Undergrad. Fluid Mechanics (shared)
ChE 466 - Process Dynamics and Control

Graduate ChE Courses

ChE 629 - Complex Fluids
ChE 696/EECS 598 Biological Application of Micro- and Nanofluidics

Extension Courses - (Chulalongkorn University, Bangkok, Thailand)

Polymer Rheology (shared)
Polymer Physics (shared)