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Examining the glass transition region of hard sphere colloids by simulations

Rogers, Steven
http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1276749504

Abstract Details

2010, Bachelor of Science (BS), Ohio University, Engineering Physics.
A recent analysis of experimental results for viscosity and diffusion coefficients as functions of the volume fraction in colloidal systems near the glass transition has uncovered a substantial discrepancy with the predictions of Mode Coupling Theory (MCT). Considering the degree of difficulty of the experiments, and in particular the difficulty in precisely determining the volume fraction for the systems under study, it hasn't been clear to what degree the discrepancy comes from inaccurate experimental values and to what degree it comes from failure of Mode Coupling Theory. The goal of this project was to shed light on this question by using computer simulations. We have used molecular dynamics to simulate a binary hard sphere colloidal system consisting of 8000 particles interacting via a Weeks-Chandler-Andersen (WCA) pair potential. Our simulations covered temperatures of 0.1 and 0.01 in LJ units and volume fractions between 0.006 and 0.69. We found that as the volume fraction increased, there was a sharp decrease in the product of diffusion coefficient and viscosity. Our results are in qualitative agreement with the available experimental data, but differ significantly from the Mode Coupling Theory predictions. We suggest a possible interpretation of these results in that they provide evidence for the presence of dynamical heterogeneities - strong spatial fluctuations in the relaxation rate in glass forming liquids.
Horacio Castillo (Advisor)
44 p.
Physics
glasses; simulations; hard-spheres

Recommended Citations

Citations

  • Rogers, S. (2010). Examining the glass transition region of hard sphere colloids by simulations [Undergraduate thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1276749504

    APA Style (7th edition)

  • Rogers, Steven. Examining the glass transition region of hard sphere colloids by simulations. 2010. Ohio University, Undergraduate thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1276749504.

    MLA Style (8th edition)

  • Rogers, Steven. "Examining the glass transition region of hard sphere colloids by simulations." Undergraduate thesis, Ohio University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1276749504

    Chicago Manual of Style (17th edition)

ouhonors1276749504
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© 2010, all rights reserved.
This open access ETD is published by Ohio University Honors Tutorial College and OhioLINK.