Conformational variability of intrinsically isotropic polymers with varying stiffness immersed in nematogenic solvents

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We examined the conformation of polymer chains with varying stiffness, immersed in a nematic liquid crystal solvent of varying qualities due to the known ability of nematogenic solvents to elongate and align polymer chains. Using a coarse-grained model and molecular dynamics simulations, we considered single- and multi-chain polymer systems in both isotropic and nematic solvent mesophases. In the isotropic regime, chains exhibited a typical range of conformations from globular to random coil, while in the nematic regime, chains displayed a globular conformation with poorer solvent quality or anisotropic alignment with better solvent quality. Higher polymer stiffness and the application of an alignment field to enhance the long-range orientation order of solvent particles further improved chain anisotropic alignment. We also observed that polymer chains locally disrupted the nematic ordering of nearby solvent particles. Both stiffness-added single- and multi-chain systems in a nematic solvent spent a fraction of time in configurations with hairpin defects, similar to phenomena observed in biopolymers. We hope that molecular-level insights into the interplay between nematogenic solvent quality, polymer stiffness, and concentration will be useful in designing processes to create anisotropic chain conformations of polymers of inherently isotropic chemistries.