Xiaoli Sun, Xiying Dai, Shouke Yan
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
The one dimensional (1D) polymer nanostructures with controlled morphologies and properties can be easily achieved from Anodized aluminum oxide (AAO) template. In AAO template, confinement effect and interface effect determine the crystallization and dynamical behavior.[1-4] Some aspects of questions are worthwhile for deeper understanding: (1) discrimination between the interfacial and confinement effect on the dynamics of multiscale chain-motions; (2) discrimination between segmental dynamics and chain dynamics on the crystallization of polymer. Moreover, the studies on the comparison of confinement effect between 1D polymer nanostructures and two dimensional (2D) polymer thin film by employing the same polymer is also less explored. In the present study, poly(3-hydroxybutyrate) (PHB) was selected as a model to explore the above aspects. Interfacial effect slows down the dynamics of PHB segmental mobility and shows strong dependence on pore size. Spatial confinement accelerates the dynamics of segmental mobility. Both effects slow down the chain mobility which consequently slow down the crystallization kinetics of PHB. The inhibited crystallization of PHB in AAO nanopores can be attributed to both segmental and chain mobility. By contrast, only chain mobility plays the role on the crystallization of thin film. Segmental mobility does not change with film thickness.
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