Dr. Joseph Samaniuk

ETH Zurich, Switzerland

Structure and rheology of insoluble polymers at an air-water interface

Abstract

Polymers at interfaces are important in biology and chemistry, and have commercial applications in products like paints, cosmetics, food stuffs, and composite materials. The structure and rheology of insoluble polymers spread at an air-water interface, specifically whether these polymers adopt an entangled structure that manifests a clear rheological fingerprint, has recently been contested. We have investigated this by measuring the interfacial rheological properties of poly(tert-butyl methacrylate), poly(tert-butyl acrylate), and poly(methyl methacrylate) of different molecular weights and topologies at an air-water interface. Both shear and dilatational rheological results were obtained at monolayer coverage, and phase-contrast microscopy was used for observing film heterogeneities. The results support the theory that polymer molecules at an air-water interface act as glass-like blobs without significant molecular entanglements. When formed into a single-molecule thick layer at an air-water interface, they exhibit soft-glassy rheology.



Date: 20/11/2015
Time:12:00 (coffee & cookies will be served at 00:00)
Place:FORTH Seminar Room 2