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Thermophysical and mechanical properties of two conjugated polymers, poly(p‐phenylene vinylene) (PPV) and polyacetylene (PA), are predicted using molecular dynamics simulations and compared with results obtained from differential scanning calorimetry, nanoindentation, and dynamic mechanical analysis experiments. Glass transition temperature (Tg) is calculated from the changes in the slopes of the specific volume versus temperature and cohesive energy density versus temperature plots, obtained from constant pressure and constant temperature simulations (NPT ensemble). The effects of temperature on the torsion angle distributions and characteristic ratio are analyzed. PPV is found to have a Tg of 416 ± 8 K. PA does not exhibit a glass transition in the temperature range of 120 to 500 K. Using the static deformation method, the values of Young's modulus are calculated to be 1.81 ± 0.34 GPa for PA and 9.20 ± 0.57 GPa for PPV at 298 K. These values are in good agreement with the experimental measurements, validating the suitability of these techniques in the prediction of the polymer properties.

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Front Cover: The glass transition behaviors and mechanical properties of the π‐conjugated polymers, polyacetylene (PA) and poly(para‐phenylene vinylene) (PPV), are predicted using atomistic simulations and compared with experimental measurements. The cover shows a molecular dynamics simulation box consisting of PPV molecules. The box, each side of which is about 7.4 nm, is filled with 60 polymer chains that are 40 monomer units long. The stresses generated upon subjecting the simulation box to small deformations are calculated employing force field parameters, and then used to determine the Young's modulus and the Poisson's ratio of the polymer. Also shown are representative data from nanoindentation measurements of PA and PPV at room temperature. Further details, including the temperature variations of the specific volumes, the cohesive energy densities, the torsion angle distributions, and the characteristic ratios of the two polymers, can be found in the article by Ramaswamy I. Venkatanarayanan, Sitaraman Krishnan,* Arvind Sreeram, Philip A. Yuya, Nimitt G. Patel, Adama Tandia, and John B. McLaughlin on page 238.

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