Hierarchical structure of the triclinic α-phase crystal in nylon 6,12 mediated by two-dimensional confinement

Abstract

It has been recognized that macromolecular chains can self-assemble into a hierarchical structure from lamellae to spherulites in bulk crystallization. However, little account has been taken of crystal symmetry effects on the hierarchical nanostructure in polymers under cylindrical confinement. In this research, a model polymer, nylon 6,12, most commonly occurring in the triclinic phase, was chosen in order to demonstrate the effect of triclinic symmetry on the 2D-constrained polymer nanostructure. The self-arranging unit of nylon 6,12 takes various forms, including stems, unit cells, hydrogen-bonded sheets, lamellae and complex spherulites, which is an essential structural feature for investigating hierarchical nanostructure. The rod nanostructure in confinement was examined by cross-checking electron and X-ray diffraction techniques. It is found that the a* axis of the -phase cell is inclined at about AE6-11 to the rod long axis within the a*b* plane around the c axis (c axis ? rod long axis). The rotation of the a*b* plane most likely results from the impact of the triclinic symmetry on the molecular chain packing under 2D confinement. A mechanism for this a*b* plane tilting is proposed.

Experiments on the Molecular Mechanism and Interface Structure of Pure and Doped Polymer Nanocomposites Used in Microelectronics

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Structural Ensemble of Molecular Chains in Isotactic Polypropylene under Cylindrical Confinement

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Bis(benzoxazol-2-yl)methanides in main group organometallic syntheses and enquiry-based education

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