Polymeric micro-sequential concentric transcrystalline morphology self-assembly, with intermittent self-shear-oriented amorphous layers

The investigation and understanding of polymer crystallization processes, the resulting crystalline morphologies, and the mechanism of their formation is crucial in creating materials with desired properties for specific applications. The present research introduces and investigates a new polymeric crystalline morphology, observed for the first time in this research. This newly observed morphology, is a sequentially micro-multi-layered concentric morphology that self-assembles throughout the bulk polymer matrix, with intermittent self-shear-oriented amorphous layers. The research analyses the structure and mechanism of its formation. Polarized light microscopy studies have shown a drastic and sudden morphology change that occurred during crystalline growth. Crystalline-growth kinetics studies performed, showed a distinct pulsatile repeating growth pattern of approximately two growth pulses per second. Thermal analysis indicated the presence of two different populations of crystalline strength. Crystalline structure was analyzed by XRD pattern measurements. It was demonstrated here, that the sequential concentric transcrystalline morphology is nucleated on a shear-oriented amorphous molecular layer in the adjacent melt formed during and as a consequence of crystalline growth, which occurs in a micro-periodic sequences, with intermittent self-sheared amorphous layers. The structure was confirmed by both scanning electron microscope and reflectance microscopy. Small angle X-ray scattering measurements of the same materials reported in literature are consistent with the melt shear-orientation theory described earlier. The discovery of this new crystalline morphology in this research, potentially opens a new door in the vast field of material properties and applications.