报告题目：What are typical sources of error in rotational and elongational rheometry
报 告 人：Florian Stadler (深圳大学教授)
Rheometers have made giant leaps in terms of usability, sensitivity, and versatility. This leads to the illusion that a rheometer can be used as a fool-proof device for measuring rheological properties. The presentation will focus on typical problems that are encountered in rheological practice when measuring polymer melts. Emphasis is put on problems related to measurement artefacts stemming from the rheometer as well as from the material itself. Furthermore, possibilities to eliminate rheometer related artefacts mostly related to the following phenomena - geometry inertia, geometry overfilling/underfilling, thermal expansion, torque resolution, and environmental control - will be discussed. The sample related artefacts vary significantly from sample to sample and include: thermal degradation, nonlinear shear deformation, centrifugal forces, slip and shear banding, as well as miscibility, orientation, and distribution of different phases, of which only the ones occurring in homogeneous polymer melts are discussed here. Further, artefacts in elongational rheometry are discussed as well, which are mostly related to improper sample preparation and sagging.
Dr. Florian Stadler is a distinguished professor for materials science in Shenzhen University, which he joined in 2014. He focuses on experimental rheology among other techniques for polymer chemistry and physics. Research focuses on polymer melts and ionomers as well as polymer solutions and gels with covalent and supramolecular interactions. Of special interest to him are functional polymers enabling sensing and stimuli responsiveness. Furthermore, Prof. Stadler is also involved in nanoparticle synthesis and applications, especially for solar cells. So far Prof. Stadler has published 283 academic papers on various aspects of polymer and nanoparticle science in reputable journals like Advanced Materials, Advanced Functional Materials, Nature Communications, Materials Horizons, PNAS, Macromolecules, and other excellent journals.