Speaker: John R. Dutcher, Department of Physics, Centre for Food & Soft Materials Science and Advanced Foods and Materials Network, University of Guelph, Ontario, Canada.

Title: “Instabilities And Pattern Formation In Thin Polymer Films”
 

Abstract:
Thin polymer films with thicknesses of tens of nanometers are studied extensively for both fundamental and applied reasons: (1) they provide an ideal sample geometry for studying the effects of one-dimensional confinement on the structure, morphology and dynamics of the polymer molecules; and (2) they are used extensively in technological applications such as optical coatings, protective coatings, adhesives, barrier layers and packaging materials. The stability of the films is a key issue in all of these studies and applications. For most applications, it is necessary to ensure that the film remains stable within its range of operating temperatures. However, by exploiting instabilities that are inherent to thin polymer films in response to changes in, e.g. temperature and applied fields, it is possible to learn about fundamental interactions and dynamics, and to achieve unique applications such as multilayer active packaging materials and well-ordered, self-assembled morphologies in the plane of the film with micrometer and even nanometer length scales.

In this presentation, I will describe the results of two recent studies: (1) the formation and growth of holes in freely-standing polystyrene films at elevated temperatures, which reveals detailed information about the mobility of polymer molecules confined to very thin films; and (2) and the formation and manipulation of a periodic morphology that self-assembles upon heating of freely-standing polymer trilayer films.

Host: Recep Avci