Mark Stevens

Scientist, Center for Integrated Nanotechnologies
Science Thrust:

Phone: 505-844-1937
Fax: 505-284-7778
msteve@sandia.gov

MS 1315, P.O. Box 5800                                                        
Sandia National Laboratories                                                  
Albuquerque, NM  87185


 

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Education and Training

Undergraduate: University of Cincinnati, B.A, B.S, 1984
Graduate: The Johns Hopkins Univ., Ph. D., 1991

Research

Among the tantalizing possibilities of nanotechnology are novel, composite materials with nanoparticle components that have widely diverse material properties (e.g. magnetic, optical, electronic). Nanoscience promises the ability to form complex systems composed of many types of nanoparticles, giving rise to multifunctional properties. If we consider proteins as nanoparticles, then the complexity of a cell shows how great the possibilities are. Thousands of different proteins interact within the cell and yet are organized and yield a system whose properties, including multifunctionality, arise from multiple competing interactions. Learning to exploit the full range of possibilities within such complex systems requires that we be able to calculate these interactions and understand how the structures and properties depend on them. My work involves understanding the structure and dynamics by performing molecular dynamics simulations on a variety of systems including natural systems that contain characteristics that we want to incorporate into materials. In general, nanoparticles are coated and the interaction between nanoparticles is influenced primarily by the coating. For several years, my group has worked on atomistic simulations of self-assembled monolayers studying the interactions between planar surfaces. This work now include the modeling of interactions between a tip (e.g. AFM) and a self-assembled monolayer and is evolving to treat coated nanoparticles. Another broad interest at CINT is interactions of nanoparticles with lipid bilayers. For several years, I have been performing MD simulations of lipid bilayers studying fusion and domain formation. The dynamics of membrane proteins within a lipid bilayer is now being studied and generalized to the dynamics of nanoparticles interacting with the membrane. I have a long standing interest in electrostatic interactions and charged macromolecules. Recent research has focused on the mechanical and structural properties of charge polymer brushes. Both atomistic and coarse-grained models are used to study the dynamics. The simulations are performed using the LAMMPS molecular dynamics code.

Selected Publications

  • D.S. Bolintineanu, M. J. Stevens and A.L. Frischknecht, Atomistic Simulations Predict a Surprising Variety of Morphologies in Precise Ionomers, ACS Macro Letters 2, 206 (2013).
  • A. Dickey and M. J. Stevens, Site-Dipole Field and Vortices in Confined Water, Phys. Rev. E 86, 051601 (2012).
  • M. J. Stevens, D. B. McIntosh and O. A. Saleh, Simulations of Stretching a Strong, Flexible Polyelectrolyte, Macromolecules 45, 5757, (2012).
  • Y. Ou, J.B. Sokoloff and M. J. Stevens, Comparison of shear behavior between two planar neutral brushes and polyelectrolyte brushes through molecular dynamics simulation, Phys. Rev. E 85, 011801 (2012).
  • M. J. Stevens and J.H. Hoh, Interactions between planar grafted neurofilament side-arms, J. Phys. Chem. B, 115, 7541 (2011).
  • L.M. Hall, M. J. Stevens, A. Frischknecht, Effect of Polymer Architecture and Ionic Aggregation on the Scattering Peak in Model Ionomers, Phys. Rev. Lett. 106, 127801 (2011).

Selected User Projects

  • Molecular basis for protein nanomechanics, Jan Hoh, The Johns Hopkins Medical School
  • Theory of Nanolubrication using Polymer Brushes, Jeff Sokoloff, Northeastern University.
  • Coarse-grained Computer Simulation of Self-assembly and Mechanics ofTwo-Dimensional Protein Structure, William Klug, UCLA