David M. Ronis

Address

Department of Chemistry, McGill University

Otto Maass Chemistry Building, 801 Sherbrooke Street West

Montreal, Quebec H3A 2K6, CANADA

Tel: (514) 398-5099 Fax: (514) 398-3797

Email: david.ronis@mcgill.ca

WARNING: I have continuous problems with e-mail spam and have several blocking mechanisms in place. Your messages may be silently ignored, so if you don't hear from me, please send a FAX, regular mail, phone.

Interested in working with me as a postdoc? Apply online here.

Some results of a mean-field Monte Carlo simulation
of a polyelectrolyte coated colloidal particle in dilute
and concentrated salt solutions.
(Click on the images for enlargements).

Personal Data

Research Interests

Transport in membrane and zeolite channels. In these systems, pores or channels selectively allow ions or neutral molecules to pass through the system, and play important roles in cell biology and industrial filtration processes. Our goal is to develop molecular theories of passive transport through channels in biological-membranes and zeolites that can be compared with experiment. Here are the slides of a recent talk I gave on this topic.

Static and dynamic properties of suspensions of highly charged colloidal particles. In many respects, dilute colloidal suspensions mimic atomic systems and can be used to study static and dynamic processes such as solidification, rheology, shear induced melting, and shear induced order or pattern formation. The Ronis group has developed several simple, but successful, theoretical models that explain many features of experiments on these systems.

Correlations and conformations in polymer-coated colloids. An key way in which colloidal suspensions are stabilized is by coating the individual colloidal particles with charged or neutral polymer chains that keep the particles from coming into contact and flocculating. Here we are developing theories to describe the coupled intra- and inter-particle interactions in systems comprised of colloidal particles coated with charged or neutral, polymeric chains, (e.g, as shown above). Our goal is to quantitatively answer the following questions: How to calculate the average distribution of neighboring colloids around any particle? What is the distribution of counter-ions in the polymer layer and in the space between the colloidal particles? What is the polymer configuration and how does it change when macroscopic conditions change? What is the degree of overlap of polymer layers? What if the monomers are reactive (e.g., they ionize or bind)? Here are the slides of a recent talk I gave on this topic.

Surface Texturing in Polymer Extrudates. We have recently developed a simple theory that explains the defect texturing seen on the surfaces of extruded plastics. Our approach, while mathematically simple, brings together many ideas from works on hydrodynamics and rheology, reptation physics, the kinetics of phase transitions, and dynamical systems analysis and chaos, and describes a surprisingly rich range of phenomena including chaotic behavior (here is an example) and pattern formation (here is an example).

Dynamics in critical fluids far from equilibrium. We are studying turbulent fluid flow and its effects on the thermodynamics and kinetics of phase transitions in binary liquid mixtures using renormalization-group methods.

Energy-Transfer. The mechanisms of radiative energy-transfer processes in microparticles can differ from those in the bulk, and experiments find large enhancements in the quantum yield for transfer and anomalous kinetics. We are using electrodynamic, multiple-scattering methods to explain this phenomena with applications to colloidal and cellular systems.

Representative Publications

• M. Vertenstein and D. Ronis, Microscopic Theory of Membrane Transport III: Transport in Multiple Barrier Systems, J. Chem. Phys. 85, 1628 (1986).
  
  
• D. Ronis and S. Khan, Stability and Fluctuations in Sheared Colloidal Crystals, , Phys. Rev. A, 42, 4694 (1990).
  
  
• J.-Y. Yuan and D. Ronis, Instability and pattern formation in colloidal suspension Taylor-Couette flow, Phys. Rev. E 48, 2280 (1993).
  
  
• D. Ronis, Statistical mechanics of ionomeric colloids: thermodynamics, correlations, and scattering, Phys. Rev. A 44, 3769 (1991).
  
  
• D. Ronis, Statistical mechanics of ionomeric colloids II: Ionomer Conformational Equilibria, Macromolecules 26, 2016 (1993).
  
  
• D. Ronis, Statistical mechanics of ionic colloids: Interparticle correlations and conformational equilibria in suspensions of polymer coated colloids, Phys. Rev. E 49, 5438 (1994).
  
  
• Y. Drossinos and D. Ronis, Critical Dynamics of Unstable States, Phys. Rev. B 42, 4694 (1990).
  
  
• J.-Y. Yuan and D. Ronis, Theory of fully developed hydrodynamic turbulent flow: Applications of renormalization group methods, Phys. Rev. A 45, 5578-5595 (1992).
  
  
• A. C. Pineda and D. Ronis, A Classical Model for Energy Transfer in Microspherical Droplets, Phys. Rev. E 52, 5178-5194 (1995).
  
  
• B. Morin and D. Ronis, Disorder and Order in Sheared Colloidal Suspensions, Phys. Rev. E 54, 576 (1996).
  
  
• J. D. Shore, D. Ronis, L. Piche, and Martin Grant, Model for melt fracture instabilities in capillary flow of polymer melts, Phys. Rev. Lett. 77, 655 (1996).
  
  

Some Preprints and Reprints (NEW)

• T. Croteau and D. Ronis, Non-equilibrium velocity distributions in liquids: Systems under shear, Phys. Rev. E 66, 066109 (2002)
• B. Palmieri and D. Ronis, Diffusion in channeled structures: Xenon in crystalline sodalites, Phys. Rev. E, Phys. Rev. E, 68, 046127 (2003).
• Benoit Palmieri and David Ronis, Diffusion in channeled structures II: Systems with large energy barriers, J. Phys. Chem. B, 109, 21334 (2005).
• Benoit Palmieri and David Ronis, Effective classical partition functions with an improved time-dependent reference potential , Phys. Rev. E, 73, 061105 (2006).
• David L. Kolin, David Ronis and Paul W. Wiseman, k-Space Image Correlation Spectroscopy: A Method for Accurate Transport Measurements Independent of Fluorophore Photophysics , Biophys. J., 91, 3061 (2006).
• Benoit Palmieri and David Ronis, The Jarzynski equality: Connections to thermodynamics and the Second Law, Phys. Rev. E, 75, 011133 (2007).
• Benoit Palmieri and David Ronis, Diffusion in Channeled structures III: Quantum corrections induced by lattice vibration, Phys. Rev. E, 76, 011124 (2007).
• David Ronis, Response Theory and Reduced Equations of Motion, Phys. Rev. E, 79, 031106 (2009).
• Carl Bartels and David Ronis, Competition between conformational and chemical equilibrium in suspensions of polyelectrolyte coated particles, Macromolecules, 44, 3174-3178 (2011).

Here are some useful links

• McGill Department of Physics Homepage
• Preprint Database
• Chemical-Physics Preprint Database
• Condensed-Matter Physics Preprint Database

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Links to My Past and Present Course Pages

• Chemistry CHEM223, Introductory Physical Chemistry 1
• Chemistry CHEM243, Introductory Physical Chemistry 2
• Chemistry CHEM345, Molecular Properties and Structure 1
• Chemistry CHEM365, Statistial Thermodynamics
• Chemistry CHEM593, Statistical Mechanics
• Chemistry CHEM646, Advanced Statistical Mechanics
• Chemistry CHEM213, Introductory Physical Chemistry (No longer offered)
• Chemistry CHEM293, Chemistry for Civil Engineers (No longer offered)