Many mechanical, dynamical and structural properties of materials remain poorly understood for reasons independent of system-specific chemistry. Great advances in understanding these properties can be achieved through coarse-grained and multiscale simulations that are computationally efficient enough to access experimentally accessible spatiotemporal scales yet "chemically" realistic enough to capture the essential physics underlying the properties under study. I have and will continue to concentrate on explaining poorly-understood behaviors of polymeric, colloidal, and nanocomposite systems through coarse-grained modeling and concomitant development of analytic theories. The general theme is to do basic research on topics that are of high practical interest. More details can be found on my CV. I joined the Department of Physics at the University of South Florida as an assistant professor in Fall 2012, and am actively recruiting Ph.D. students. If you are interested in joining my group, please contact me.



People

Collaborators: Ayman Abouraddy, Josef Jancar, Nikos Ch. Karayiannis
Current students: Hong Nguyen
Alumni: Tyler Smith, Krystle Quinn, Arvind Srikanth, Earl Johnson, Brandon Sweeting

The group in Spring 2015: Rob Hoy, Tyler Smith,
Krystle Quinn, Hong Nguyen, and Andrew Stevens
from left to right.

Contact Info

University of South Florida
Department of Physics, ISA 4209
Tampa, FL 33620-5700
Phone: 813-399-2976
Fax: 813-974-5813
email: rshoy at usf dot edu

News

Our NSF-CAREER proposal "Fundamental Studies of Glassy Polymer Mechanics" was funded! The funds will support two graduate students, as well as education efforts associated with USF's APS Bridge Program.

Congratulations to group alumni Tyler Smith and Krystle Quinn! Tyler enrolled in the Physics Ph.D. program at Emory, and Krystle accepted a software design position at Raytheon Corp.

Our recent work on enumerating sticky sphere packings was featured in the November-December 2012 issue of American Scientist. You can view the article online or in PDF form here.

Papers

Jamming of Semiflexible Polymers
R. S. Hoy
Physical Review Letters v. 118, 068002 (2017) (pdf)

Entanglements in Glassy Polymer Crazing: Cross-Links or Tubes?
T. Ge, C. Tzoumanekas, S. Anogiannakis, R. S. Hoy and M. O. Robbins
Macromolecules v. 50, 459 (2017) (pdf)

Effect of chain stiffness and temperature on the dynamics and microstructure of crystallizable bead-spring polymer melts
H. T. Nguyen and R. S. Hoy
Physical Review E v. 94, 052502 (2016) (pdf)

Controlled fragmentation of multimaterial fibres and films via polymer cold-drawing
S. Shabahang, G. Tao, J. J. Kaufman, Y. Qiao, L. Wei. T. Bouchenot, A. P. Gordon, Y. Fink, Y. Bai, R. S. Hoy, and A. F. Abouraddy
Nature v. 534, 529 (2016) (pdf)

Effect of chain stiffness on the competition between crystallization and glass-formation in model unentangled polymers
H. T. Nguyen, T. B. Smith, R. S. Hoy and N. Ch. Karayiannis
J. Chem. Phys. v. 143, 144901 (2015) (pdf)

Effect of temperature, strain rate, and particle size on the yield stresses and post-yield strain softening of PMMA and its composites
J. Jancar, R. S. Hoy, E. Jancarova and J. Zidek
Polymer v. 63, 196 (2015) (pdf)

Structure and dynamics of model colloidal clusters with short-range attractions
R. S. Hoy
Physical Review E, v. 91. 012303 (2015) (pdf)

Role of Entanglements and bond scission in high strain-rate deformation of polymer gels
Y. R. Sliozberg, R. S. Hoy, R. A. Mrozek, J. L. Lenhardt and J. W. Andzelm
Polymer v. 55, 2543 (2014) (pdf)

Effect of Particle Size, Temperature, and Deformation Rate on the Plastic Flow and Strain Hardening Response of PMMA Composites
J. Jancar, R. S. Hoy, A. J. Lesser, E. Jancarova and J. Zidek
Macromolecules v. 46, 9409 (2013) (pdf)

Particle-scale reversibility in athermal particulate media below jamming
C. F. Schreck, R. S. Hoy, M. D. Shattuck and C. S. O'Hern
Physical Review E, v. 88, 052205 (2013) (pdf)

Nonlinear mechanics of thermoreversibly associating dendrimer glasses
A. Srikanth, R. S. Hoy, B. C. Rinderspacher and J. W. Andzelm
Physical Review E, v. 88, 042607 (2013) (pdf)

Simple model for chain packing and crystallization of soft colloidal polymers
R. S. Hoy and N. Ch. Karayiannis
Physical Review E, v. 88, 012601 (2013) (pdf)

Minimal energy packings of nearly flexible polymers
R. S. Hoy, J. Harwayne-Gidansky and C. S. O'Hern
Journal of Chemical Physics, v. 138, 054905 (2013) (pdf)

Structure of finite sphere packings via exact enumeration: Implications for colloidal crystal nucleation
R. S. Hoy, J. Harwayne-Gidansky, and C. S. O'Hern
Physical Review E, v. 85, 051403 (2012) (pdf)

Glassy dynamics of crystallite formation: The role of covalent bonds
R. S. Hoy and C. S. O'Hern
Soft Matter, v. 8, 1215 (2012) (pdf)

Why is Understanding Glassy Polymer Mechanics So Difficult?
R. S. Hoy
J. Polym. Sci. Part B - Polym. Phys. v. 49, 979 (2011) (pdf)

End grafted polymer nanoparticles in a polymeric matrix: Effect of coverage and curvature
J. Kalb. D. Dukes, S. K. Kumar, R. S. Hoy and G. S. Grest
Soft Matter, v. 7, 1418 (2011) (pdf)

Viscoplasticity and large-scale chain relaxation in glassy-polymeric strain hardening
R. S. Hoy and C. S. O'Hern
Physical Review E, v. 82, 041803 (2010) (pdf)

Minimal energy packings and collapse of sticky tangent hard-sphere polymers
R. S. Hoy and C. S. O'Hern
Physical Review Letters, v. 105, 068001 (2010) (pdf)

Strain hardening in bidisperse polymer glasses: Separating the roles of chain orientation and interchain entanglement
R. S. Hoy and M. O. Robbins
Journal of Chemical Physics v. 131, 244901 (2009) (pdf)

Thermoreversible associating polymer networks: I. Interplay of thermodynamics, chemical kinetics, and polymer physics
R. S. Hoy and G. H. Fredrickson
Journal of Chemical Physics v. 131, 224902 (2009) (pdf)

Topological analysis of polymeric melts: Chain-length effects and fast-converging estimators for entanglement length
R. S. Hoy, K. Foteinopoulou, and M. Kröger
Physical Review E v. 80, 031803 (2009) (pdf)

Scaling of the strain hardening modulus of glassy polymers with the flow stress
M. O. Robbins and R. S. Hoy
J. Polym. Sci. Part B - Polym. Phys. v. 47, 1406 (2009) (pdf)

Strain hardening of polymer glasses: Entanglements, energetics and plasticity
R. S. Hoy and M. O. Robbins
Phys. Rev. E v. 77, 031801 (2008) (pdf)

Entanglements of an end-grafted polymer brush in a polymeric matrix
R. S. Hoy and G. S. Grest
Macromolecules v. 40, 8389 (2007) (pdf)

Strain hardening in polymer glasses: Limitations of network models
R. S. Hoy and M. O. Robbins
Phys. Rev. Lett. v. 99, 117801 (2007) (pdf)

Strain hardening of polymer glasses: Effect of entanglement density, temperature, and rate
R. S. Hoy and M. O. Robbins
J. Polym. Sci. Part B - Polym. Phys. v. 44, 3487 (2006) (pdf)

Effect of equilibration on primitive path analyses of entangled polymers
R. S. Hoy and M. O. Robbins
Phys. Rev. E v. 72, 061802 (2005) (pdf)

Fcc-bcc transition for Yukawa interactions by applied strain deformation
R. S. Hoy and M. O. Robbins
Phys. Rev. E v. 69, 056103 (2004) (pdf)