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Helix formation in linear achiral dendronized polymers: A computer simulation study

May 9th, 2010 Comments off

D. K. Christopoulos, A. F. Terzis, A. G. Vanakaras and D. J. Photinos, J. Chem. Phys., 125, 204907 (2006).

Abstract: We present a molecular simulation study of the structure of linear dendronized polymers. We use excluded volume interactions in the context of a generic coarse grained molecular model whose geometrical parameters are tuned to represent a poly(paraphenylene) backbone with benzyl ether, Frechet-type dendrons. We apply Monte Carlo sampling in order to investigate the formation of packing-induced chiral structures along the polymer backbone of these chemically achiral systems. We find that helical structures can be formed, usually with defects consisting of domains with reversed helical handedness. Clear signs of helical arrangements of the dendrons begin to appear for dendritic generation g=4, while for g=5 these arrangements dominate and perfect helices can be observed as equilibrium structures obtained from certain types of starting configurations.

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Self-Organization and Pattern Formation of Janus Particles in Two Dimensions by Computer Simulations

May 9th, 2010 Comments off

A. G. Vanakaras, Langmuir, 22, 88-93 (2006).

Abstract: The phase behavior and associated pattern formation of two-dimensional systems of hard disks decorated with amphiphilic coronae (Janus disks) are studied by means of Monte Carlo computer simulations. A primitive interaction potential that captures the essential interparticle interactions is introduced. Despite its simplicity, the system exhibits a very rich phase polymorphism. Apart from the isotropic phase and depending upon the coronal thickness, the simulated systems self-organize in a number of two-dimensional mesophases of various symmetries exhibiting a variety of novel patterns. The results of these simulations suggest that 2D Janus particles are promising candidates for bottom-up design of precise two-dimensional templates.

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