Growth Rate of Spherulites in Thin Films: Direct Evidence of Failure of Traditional Growth Theory

Abstract

Growth rates of PPS and PVDF spherulites in very thin films were measured. The growth rates change by about four orders of magnitude within the crystallization temperature ranges examined in this work. Film thickness at the position of the spherulite for which growth rates were determined was measured; the film thickness was deduced from retardation in the spherulite. In the light of the criterion we proposed, film thicknesses more than several tens of microns are required for the growth rate to change by four orders of magnitude. However, the thickness of the thinnest film examined experimentally was less than 1 μm. This discrepancy between theory and experiment is large and violates the framework of the traditional growth model unrecoverably.