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Annealing And Recrystallization Of Single Crystals Of Polyethylene On Graphite: An Atomic Force Microscopy Study, Sergei Magonov, Natalya Yerina, Yuli Godovsky, Darrell Reneker
Annealing And Recrystallization Of Single Crystals Of Polyethylene On Graphite: An Atomic Force Microscopy Study, Sergei Magonov, Natalya Yerina, Yuli Godovsky, Darrell Reneker
Darrell Hyson Reneker
In situ and ex‐situ atomic force microscopy (AFM) studies of annealing of solution‐grown single crystals of polyethylene (PE) on graphite were performed at temperatures up to 170°C. Structural changes of the crystals began at ∼90°C at the interface between the lamellar crystal and the substrate where solvent traces are likely trapped after crystal collapse. Initially, material at the edges and in a few central locations of the lozenge‐shaped crystals was converted into 20 nm wide and 3 nm thick strands. As annealing temperature increases, this transformation spreads over the whole crystal, and at 110°C the arrays of the strands, which …
Effects Of Photointensity Gradient On Directional Crystal Growth In Blends Of Crystalline Polymer And Photoreactive Monomer Undergoing Photopolymerization-Induced Phase Transformation, Pankaj Rathi, Soo Park, Thein Kyu
Effects Of Photointensity Gradient On Directional Crystal Growth In Blends Of Crystalline Polymer And Photoreactive Monomer Undergoing Photopolymerization-Induced Phase Transformation, Pankaj Rathi, Soo Park, Thein Kyu
Thein Kyu
Effects of light intensity gradient on development of intricate hierarchical morphology of semicrystalline polyethylene oxide (PEO) and photoreactive diacrylate (DA) blends undergoing photopolymerization-induced crystallization have been demonstrated experimentally and theoretically. The melting temperature of PEO was found to decline upon addition of DA monomer. A solid-liquid phase diagram has been established by self-consistently solving the combined phase field free energy of crystal solidification and Flory-Huggins (FH) free energy of liquid-liquid demixing. Dynamic calculations were performed using time-dependent Ginzburg-Landau (model C) equations by incorporating the combined phase field and FH free energy densities coupled with the photopolymerization kinetics. The spatiotemporal development …