Biographical Information

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

Education

Professional Experience

Recent Honors and Awards

Professional Service

Research Interests

Rheology of Complex Fluids. Many everyday substances are not readily classified as solids or liquids, but have flow properties somewhere in between. Examples include mayonnaise, toothpaste, and silly putty. 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, I am trying to work out the relationship between the structure of complex fluids and their rheology. Such knowledge is valuable in the optimal design of such fluids for applications in the polymer, pharmaceutical, and electronics industries. Of particular interest at present are branched polymer melts, surfactant solutions, and biopolymers. For a movie showing the measurement of the extensional rheology of polymer melts, click here.

Flow Properties of Biomolecules. An area of rapidly growing interest is the micromanipulation of biomolecules such as DNA, for genome analysis and other applications. Using theories of polymer flow dynamics adapted to DNA molecules, combined with microscopy experiments, we are attempting to facilitate the use of flow fields for manipulating DNA and other biomolecules. For a video showing experimental and simulated imagespolymer/ of a DNA molecule stretching in an extensional flow, go to the DNA page.

Simulation of Surfactant and Lipid Microstructures. Because of increases in computer speed, lattice simulation methods such as Monte Carlo sampling can now be used to predict the structure and self assembly of complex microstructures including micelles, liquid crystalline phases and their phase diagrams. My group is developing fast lattice methods that can be used to determine the relationship between molecular architecture and the self-assembled structure. Recent work concentrates on polymer/surfactant complexes, including micellization along polymer chains. We have determined the structures of micelles formed from mixed surfactants, including the formation of rod-like micelles and a very unusual donut-shaped micelle. We are also using molecular dynamics methods to simulate lipid/protein interactions, including the proteins in lipid membranes. We are especially interested in the structure of lung surfactant, which contains not only surfactants, but proteins which are responsible for the ability of lung surfactant to expand and compress without collapse. The absence of the protein SP-B in the lungs of pre-mature infants is believed to be responsible for respiratory distress syndrome, the most serious life-threatening condition common in infants of fewer than 26 weeks gestation. Our molecular dynamics simulations are attempting to determine the location and orientation of the SP-B protein in a monolayer of lung surfactant.

Viral Genomics Using Microfrabricated Devices (with Burns, Solomon, Burke and Fuller) We are developing microfabricated devices capable of distinguishing variations in viruses by detecting differences in their genomes. Such devices would allow cheap, portable, rapid diagnosis of variations in rapidly mutating viruses, such as influenza.

Graduate Students:

Xue Chen (PhD candidate)
Indranil Saha Dalal (PhD candidate)
Susan Duncan (PhD candidate)
Laura Shereda (PhD candidate) (joint with Mike Solomon)
Nobuhiko Watari (PhD candidate)

Post-docs:

Nazish Hoda
Zhicheng Log
Zuowei Wang

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)