Probing the Nano-Assembly Leading to Periodic Gratings in Poly(p-dioxanone)

This study used scanning electron microscopy via 3D dissection coupled with synchrotron radiation with microfocal beams of both small-angle X-ray scattering and wide-angle X-ray diffraction to analyze the periodic crystal aggregates of unusual poly(p-dioxanone) (PPDO) dendritic cactus-arm-like ring bands upon crystallization with a diluent poly(vinyl alcohol) (PVA) that is capable of hydrogen bonding interactions with PPDO. Three-dimensional microscopy interior dissection clearly expounds that the banded periodic architectures are packed by alternately normal-oriented flat-on crystals underneath the valley, periodically interfaced/branched with horizontal-oriented edge-on fibrils underneath the ridge. The oblique angles between the valley's flat-on crystals with the branches are ca. 25-45(degrees) (depending on gradient inclines and bending), which is also proved by the azimuthal angle in microbeam X-ray diffraction. The grating-like strut-rib assembly in the PPDO cactus-arm-like ring bands is further proved by novel iridescence tests.

Automated summary

This study used scanning electron microscopy and synchrotron radiation to analyze the crystal aggregates formed by poly(p-dioxanone) and poly(vinyl alcohol) during crystallization. The results showed that the periodic architectures were formed by alternating flat crystals and fibrils, with an oblique angle between the branches and the flat crystals.