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Morphology Development In Main-Chain Liquid Crystalline Polymer Fibers During Solvent Evaporation, Pratyush Dayal, Andrew Guenthner, Thein Kyu
Morphology Development In Main-Chain Liquid Crystalline Polymer Fibers During Solvent Evaporation, Pratyush Dayal, Andrew Guenthner, Thein Kyu
Thein Kyu
A nonequilibrium thermodynamic approach has been developed for describing the emergence of fiber morphologies from a liquid crystalline polymer solution undergoing solvent evaporation, including fibrillar structures, concentric rings, and spiral structures. We utilized Matsuyama–Kato free energy for main-chain liquid crystalline polymer (MCLCP) solutions, which is an extension of Maier–Saupe theory for nematic ordering and incorporates a chain-stiffening, combined with Flory-Huggins free energy of mixing. Temporal evolution of the concentration and nematic order parameters pertaining to the above free energy density of liquid crystalline polymer solution was simulated in the context of time-dependent Ginzburg–Landau theory coupled with the solvent evaporation rate …
Morphology Development In Polymer Fibers Undergoing Solvent/Non-Solvent Exchange, Pratyush Dayal, Thein Kyu
Morphology Development In Polymer Fibers Undergoing Solvent/Non-Solvent Exchange, Pratyush Dayal, Thein Kyu
Thein Kyu
The solvent/non-solvent interchange across the fiber surface affects the morphology of the fiber in various ways. In this paper, simulations have been performed to elucidate the diverse morphologies obtained during spinning of polymer fibers under the presence of a non-solvent. The proposed model deals with a ternary system derived from Cahn-Hilliard equation, alternatively known as Time Dependent Ginzburg Landau-TDGL model B equation, involving the spatio-temporal evolution of concentration order parameter. Depending on the coexistence region of the ternary phase diagram, various fiber morphologies including concentric bands, internal microfibrillar structures, and porous structures were discerned. It may be inferred that the …