Eur. Phys. J. E (2003) 11: 191-198
https://doi.org/10.1140/epje/i2002-10155-4

Crystallization kinetics and crystal morphology in thin poly(ethylene oxide) films

¹ Department of Physics & Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, L8S 4M1, Canada
² Department of Physics and Guelph-Waterloo Physics Institute, University of Waterloo, Waterloo, ON, N2L 3G1, Canada

^* e-mail: dalnoki@mcmaster.ca

Received: 12 December 2002
Revised: 12 May 2003
Published online: 2 July 2003

Abstract

We present a detailed study of the kinetics of crystallization for thin films of poly(ethylene oxide) (PEO). Measurements of the growth rate have been carried out using optical-microscopy techniques on films of monodisperse PEO. Films with thicknesses from 13 nm to ~2 μm were crystallized isothermally at temperatures ~20°C below the melting point. A remarkable non-monotonic slowing-down of the crystal growth is observed for films with thickness less than ~400 nm. The changes in the growth rate from bulk-like values is significant and corresponds to a factor of 40 decrease for the thinnest films studied. The morphologies of isothermally crystallized samples are studied using atomic-force microscopy. We find that a morphology, similar to diffusion-controlled growth (dendritic growth and densely branched growth), is observed for films with h < 150 nm. In addition, changes in the morphology occur for thicknesses consistent with changes in the growth rate as a function of film thickness.