Tuesday, November 6, 2007 - 5:10 PM
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The Phase Behavior Of Mono And Ditethered Nanospheres: Effect Of Particle Size And Tether Placement

Christopher R. Iacovella1, Mark A. Horsch2, Zhenli Zhang3, and Sharon C. Glotzer1. (1) Department of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI 48109-2136, (2) Dept. of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI 48109-2136, (3) University of Michigan, Dept. of Chemical Engieering, 2300 Hayward Street, Ann Arbor, MI 48103-2136

Diblock and triblock copolymers have been found to self assemble into a wide array of complex morphologies; the use of polymer tethered nanoparticles is a unique method to control the self-assembly of nanoparticles into phases reminiscent of block copolymers. In this work we utilize Brownian dynamics simulations to investigate the phase behavior of monotethered nanospheres analogous to diblock copolymers and also perform simulations of ditethered nanospheres analogous to ABC triblock copolymers.  Specifically, we investigate the impact of nanosphere diameter [1] and nanosphere interaction [1,2]  on the phase behavior and local packing of monotethered nanospheres. We also investigate the impact of block fraction and dihedral angle, the angle separating the two tethers, on the phase behavior of ditethered nanospheres [3].

[1] C.R. Iacovella, M.A. Horsch, Z-L Zhang, S.C. Glotzer. "Phase diagrams of self-assembled mono-tethered nanospheres from molecular simulation and comparison to surfactants" Langmuir, 21 (21), 9488-9494, (2005)

[2] C.R. Iacovella, A.S. Keys, M.A. Horsch, S.C. Glotzer "Icosahedral packing of polymer-tethered nanospheres and stabilization of the gyroid phase" Phys. Rev. E 75, 040801(R) (2007)

[3] C.R. Iacovella and S.C. Glotzer, preprint.