Structure of random block copolymer melts at solid surfaces

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Using computer simulations of coarse-grained models, we investigate the molecular structure at the narrow interface and in the interphase of homopolymer and disordered, random block copolymer (RCP) melts in contact with a solid substrate. Two topics will be addressed: 1) We will investigate polydisperse systems that are characterized by a distribution of AB-sequences or molecular weights. The aim consists in exploring the coupling between the composition profile (fractionation) that a selective, solid substrate imparts onto the wide interphase of the disordered RCP, the single-chain structure and dynamics, and the local mechanical properties in the glassy state. Additionally, we will study how the presence of a solid substrate influences the polymerization process – both reversible/living as well as irreversible. 2) We will study to what extent a coarse-grained model can describe the narrow interface of a polymer melt in contact with a solid substrate. The dependence of the density profile and surface free energy on chain length and discretization, compressibility of the polymer liquid, and molecular stiffness will be investigated. We will derive a free-energy functional for the interface from simulations of a particle-based model and explore how to incorporate the properties of the narrow interface in a coarse-grained model focusing on the limiting case when the width of the interface is comparable to the size of a coarse-grained segment, the range of non-bonded interactions, or the statistical segment length.