Modeling of the shape of polyethylene oxide single crystals and determination of the kinetic crystallization parameters: Theoretical and experimental approaches

Abstract

The curvature of faces of polymer single crystals is described by the system of Mansfield equations, which is based on the Frank-Seto growth model. This model assumes the velocity of nucleus steps to be the same for their propagation to the right and left and is valid only for symmetric crystallographic planes. To describe the shape of polyethylene oxide single crystals grown from melt and limited by the {100} and {120} folding planes, it is assumed that the layer velocities to the right and left are different on {120} faces. This approach allows modeling, with a high accuracy, of the observed shapes of polymer single crystals grown at different temperatures, which makes it possible to determine unambiguously the fundamental crystallization parameters: the dimensionless ratio of the secondary homogeneous nucleation rate to the average velocities of nuclei along the crystallization planes and the ratio of nucleus velocities to the right and left. In addition, it was found that a known macroscopic single-crystal growth rate can be used to determine the absolute values of the secondary homogeneous nucleation rate and the velocities of nuclei along the growth plane.