Rasmus Bodvik, PhD Student
My work concerns polymers, primarily cellulose with modifications that give rise to a so-called negative temperature response. Such cellulose ethers phase separate at higher temperatures and some of them form gels. In some cases the viscosity increases dramatically, whereas in other cases the viscosity decreases. Remarkably, the transition from viscosity increase on heating to viscosity decrease at elevated temperatures can be induced by very small changes in the polymer architecture. The aim of this work is to understand what makes certain structure modifications significant for the temperature response and how the studied polymers can be used in surface coatings.
Light scattering has been used to study the bulk properties of the polymers. For adsorption studies DPI (Dual Polarisation Interferometry) and ellipsometry has been used and QCM-D (Quartz Crystal Microbalance with Dissipation) will be of interest further on. On other locations I have used cryo-TEM (Transmission Electron Microscopy) and SAXS (Small Angle X-ray Scattering) to study the polymer aggregation. Surface interactions between adsorbed layers can be probed by surface force measurements utilising the SFA (Surface Force Apparatus) and AFM (Atomic Force Microscope) techniques. I am also interested in the effect of additives such as anionic surfactants, non-ionic surfactants and low molecular compounds that affect hydrophobic interactions.