In-Situ Atomic Force Microscopy of Polyethylene Crystallization. 1. Crystallization from an Oriented Backbone

Abstract

Atomic force microscopy has been used to image the crystallization of polyethylene shish kebab crystals in situ, in real time, with nanometer resolution. Images of the extended chain backbone and overgrowth and subsequent interdigitation of lamellae have been obtained. Direct observation of the interdigitation process shows that the lamellae sometimes change direction so as to avoid meeting, providing evidence of the influence of a growing lamella on its surrounding environment. The growth rates of individual lamellae as they grow from the backbone have been measured and found to vary both with time and from lamella to lamella, in direct contradiction to many theories of polymer crystallization. These data, taken from the first AFM experiments to obtain such high resolution at such a high temperature during a process, provide a significant advance in the capability of AFM to increase our understanding of polymer crystallization.