The Separation of Beaded Chains in a Two Dimensional Confined Environment

The Separation of Beaded Chains
in a Two Dimensional Confined Environment

M.Sc. report, unpublished, Sept. 2012.

Justin Bondy

Department of Physics, University of Toronto,
60 St. George St., Toronto, Ontario, Canada M5S 1A7.

The goal of this project was to study two dimensional entropically driven separation of two long beaded chains. This was accomplished by placing two brass chains initially mixed in a long 2D slot and observing their behavior as the slot is shaken. The motivation for this was to create an experimental analog for the separation of chromosomes during bacterial cell division. The two main factors that were tested to see how they affect chain separation were the confinement of the chains and the asymmetry of the container they were held in. It was predicted from theory and past simulations that increasing chain confinement and container asymmetry would increase the strength of the chain separation. Three methods of analysis were performed on the experimental data. A method that measured the length of the region that the two chains were overlapping each other, as well as dividing the container into 2D and 1D grids and counting the density of beads in each bin. An surprising result was the formation of tight spiral conformations, which were not expected to be formed in the frequency/acceleration regime we were testing in. These spirals occurred in ~ 40% of all chain configurations observed and polluted the data as their ratcheting motion was not the entropically driven forces we wished to study. No discernible trends were observed with regards to the effect of confinement or container geometry on chain separation.


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