Molecular Simulations Group - publications

Monte Carlo structure factors and selected physical properties of symmetric copolymer melts at low temperatures

Wołoszczuk S.1, Banaszak M.1
  • 1Faculty of Physics, A. Mickiewicz University, ul. Umultowska 85, 61-614 Poznan, Poland
Nuclear Instruments and Methods in Physics Research B, Available online 19 April 2017, 2017
DOI: 10.1021/acs.macromol.6b02619
Abstract: Static and dynamic properties of diblock and triblock copolymer melts are simulated over a wide range of temperatures in vicinity of the order-disorder transition and also in the strong segregation regime. Dynamic Monte Carlo method, known as the Cooperative Motion Algorithm, is used with a parallel tempering scheme in order to determine a variety of physical properties. Structure factors are of particular interest since they can be directly related to Small Angle X-ray Scattering data. We also report energy, specific heat, mean-squared end-to-end distance, and the translational diffusion coefficient. Moreover, we determine order-disorder temperatures and investigate the behavior of the melts at low temperatures. We show that the finite size effects can be associated with the spatial reorientations of lamellae. Furthermore, we confirm the existence of a sharp low-temperature peak in specific heat, which we relate to the transition from a state with the diffused domain interface to a state with the sharp domain interface. The chain length dependence of the order-disorder temperatures and the interfacial smoothing temperatures are also presented. Below order-disorder transition temperature a significant loss of the chain mobility is observed, as indicated by an abrupt decrease of the diffusion coefficient.
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