Tom Haxton

Postdoctoral Fellow
Theory of Nanostructured Materials Facility
tkhaxton@lbl.gov
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Ph. D., Physics, University of Pennsylvania (2010)
S. B., Mathematics and Physics, University of Chicago (2004)


Research Interests

My research focuses on developing design rules for the self-assembly of or directed assembly of molecular building blocks into hierarchically structured materials, using a combination of statistical mechanical theory, coarse-grained and multi-scale modeling, and experimental collaborations.

Inspired by recent and ongoing experiments at the Molecular Foundry, Steve Whitelam and I developed a set of design rules for the efficient self-assembly of a model porous crystal, demonstrating two main results. First, the assembly of anisotropic components into porous structures follows very different design principles than the assembly of isotropic components into close-packed structures. Second, the optimal assembly of hierarchical structures does not necessary follow hierarchical assembly pathways.

In a Molecular Foundry collaboration with Ron Zuckermann and his lab, we have combined physical chemical, scattering, imaging, and computational approaches to understand and control the hierarchical self-assembly of peptoid polymers (synthetic isomers of peptides) into solid, free-floating bilayer nanosheets. We have discovered microscopic mechanisms by which this unique material sequentially assembles through adsorption, compression, and collapse at an air-water interface.

Publications

  • R. V. Mannige, T. K. Haxton, C. Proulx, G. L. Butterfoss, R. N. Zuckermann, and S. Whitelam, “Novel secondary structure of biomimetic polymers enables extended two-dimensional assemblies,” submitted.
  • T. K. Haxton, “High-resolution coarse-grained modeling using oriented coarse-grained sites,” J. Chem. Theory Comput. 11, 1244 (2015).
  • T. K. Haxton, R. V. Mannige, R. N. Zuckermann, and S. Whitelam, “Modeling sequence-specific polymers using anisotropic coarse-grained sites allows quantitative comparison with experiment,” J. Chem. Theory Comput. 11, 303 (2015).
  • B. Rad, T. K. Haxton, A. Shon, S.-H. Shin, S. Whitelam, and C. M. Ajo-Franklin, “Ion-specific control of the self-assembly dynamics of a nanostructured protein lattice,” ACS Nano 9, 180 (2015).
  • B. Sanii, T. K. Haxton, G. K. Olivier, A. Cho, B. Barton, C. Proulx, S. Whitelam, and R. N. Zuckermann, “Structure-determining step in the hierarchical assembly of peptoid nanosheets,” ACS Nano 8, 11674 (2014).
  • S. Whitelam, I. Tamblyn, T. K. Haxton, M. B. Wieland, N. R. Champness, J. P. Garrahan, and P. H. Beton, “Common physical framework explains phase behavior and dynamics of atomic, molecular, and polymeric network-formers,” Phys. Rev. X 4, 011044 (2014).
  • T. K. Haxton, H. Zhou, I. Tamblyn, D. Eom, Z. Hu, J. B. Neaton, T. F. Heinz, and S. Whitelam, “Competing thermodynamic and dynamic factors select molecular assemblies on a gold surface,” Phys. Rev. Lett. 111, 265701 (2013).
  • T. K. Haxton and S. Whitelam, “Do hierarchical structures assemble best via hierarchical pathways?,” Soft Matter 9, 6851 (2013).
  • L. J. Daniels, T. K. Haxton, N. Xu, A. J. Liu, and D. J. Durian, “Temperature-pressure scaling for air-fluidized grains on approaches to Point J,” Phys. Rev. Lett. 108, 138001 (2012).
  • T. K. Haxton and S. Whitelam, “Design rules for the self-assembly of a protein crystal,” Soft Matter 8, 011503 (2012).
  • T. K. Haxton, “Ratio of effective temperature to pressure controls the mobility of sheared hard spheres,” Phys. Rev. E 85, 011503 (2012).
  • M. Schmiedeberg, T. K. Haxton, S. R. Nagel, and A. J. Liu, “Mapping the glassy dynamics of soft spheres onto hard-sphere behavior,” EPL 96, 36010 (2011).
  • T. K. Haxton, M. Schmiedeberg, and A. J. Liu, “Universal jamming phase diagram in the hard-sphere limit,” Phys. Rev. E 83, 031503 (2011).
  • T. K. Haxton and A. J. Liu, “Kinetic heterogeneities at dynamical crossovers,” EPL 90, 6604 (2010).
  • N. Xu, T. K. Haxton, A. J. Liu, and S. R. Nagel, “Equivalence of glass transition and colloidal glass transition in the hard-sphere limit,” Phys. Rev. Lett. 103, 245701 (2009). Editor's suggestion. Physics synopsis
  • T. K. Haxton and A. J. Liu, “Activated dynamics and effective temperature in a steady state sheared glass,” Phys. Rev. Lett. 99, 195701 (2007).