Berlin 2015 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 64: Flow-Induced Structures in Complex Fluids (with DRG, Deutsche Rheologische Gesellschaft, and DY)

CPP 64.9: Vortrag

Donnerstag, 19. März 2015, 11:45–12:00, C 264

Combined rheo-optics and rheo-scattering study of structure evolution in biobased liquid-crystalline polymers — •Dietmar Auhl¹, Carolus Wilsens¹, Eric Stellamanns², and Sanjay Rastogi¹ — ¹Maastricht University, Maastricht, The Netherlands — ²Photon Science DESY, Hamburg, Germany

Thermotropic liquid-crystalline polymers (TLCP) are often used in high-performance applications, for which the chemical composition and flow effects on the micro- and mesoscale orientation need to be well designed. Recently developed TLCP based on p-hydroxybenzoic acid, suberic acid, and vanillic acid are partially aliphatic in contrast to commercial TLCP such as "Vectra", and they exhibit stable nematic melt morphologies up to 300°C [1,2]. In this study, we investigate the effects of temperature, shear deformation and rate on the molecular orientation and relaxation by rheo-optics as well as rheo-scattering with x-ray and small-angle light-scattering. The results show that the threaded morphology on a mesoscale breaks and orients along the flow direction under continuous flow, while also the molecules orient on a microscopic scale. The study provides detailed insights into the structure evolution of TLCP and a unique toolbox to correlate molecular parameters to properties and performance. [1] Wilsens, C., Noordover, B., Rastogi, S. Polym. (2014) 2432; [2] Wilsens, C., Verhoeven, J., Noordover, B., Hansen, M., Auhl, D., Rastogi, S. (2014) 3306