Thermodynamic and Transport Properties of Polyhedral Oligomeric Sislesquioxanes in Poly(dimethylsiloxane)

J. Phys. Chem. B, 109 (30), 14300 -14307, 2005. 10.1021/jp045388p S1089-5647(04)05388-X
Web Release Date: July 8, 2005

Thermodynamic and Transport Properties of Polyhedral Oligomeric Sislesquioxanes in Poly(dimethylsiloxane)

Alberto Striolo,* Clare McCabe, and Peter T. Cummings

Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235

Received: October 9, 2004

In Final Form: April 27, 2005

Abstract:

Polyhedral oligomeric silsesquioxane (POSS) molecules when functionalized appropriately and dispersed in polymers show promise as monodisperse organic-inorganic hybrid nanocomposite materials characterized by superior mechanical properties. We report here molecular-simulation results for POSS-POSS radial distribution functions, potentials of mean force, and self-diffusion coefficients for POSS monomers dissolved in poly(dimethylsiloxane) in the temperature range of 300-1000 K. Our results demonstrate that it is possible to modulate the effective POSS-POSS interaction by increasing the temperature or by substituting the hydrogen atoms in the POSS monomer with methyl groups. In addition, our results indicate that the motion of POSS monomers dissolved in poly(dimethylsiloxane) follows a hopping mechanism.

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