Speaker：Prof.EvelyneVan Ruymbeke

Time：May 30th, 2025 at 10:00 AM

Location: Lecture Room 324,AISMST

Abstract:

Understanding and tailoring the viscoelastic response ofpolymer melts or concentrated solutions from the knowledge of their molecularstructure (architecture) represents a formidable challenge and remains animportant field of soft matter research. In order to further study the dynamicsof these samples, we have developed a general coarse-grained approach based onthe tube model, that we are now using as a tool to investigate the viscoelasticproperties of complex, entangled polymer architectures.

In the present work, we extend this approach toinvestigate the dynamics of reversible polymer networks, containingsupramolecular junctions. The combination of stickers, exchangeable bonds andentanglements as topological constraints provides a large room to modulate theviscoelastic response of the networks. On one hand, the network elasticitydepends on the density of the reversible junctions but also on theentanglements trapped within the network, the proportion of which depends onthe topology of the building blocks. On the other hand, the relaxation time ofthe network depends on the cooperative effects of the stickers, dangling endsand entanglements, their corresponding lifetimes being a function of the samplecomposition.

Considering these different mechanisms, we showthat it is possible to design very different transient networks but withexactly the same linear viscoelastic response at a specific temperature. Butinterestingly, these networks do not behave similarly at another temperature orunder large deformation. This opens new possibilities to further control thenetworks dynamics, towards the design of samples with desired properties.

Biography: 

Since 2012, Prof. Evelyne van Ruymbeke is Senior ResearchAssociate of the FNRS and Professor at UCL working at the Institute ofCondensed Matter and Nanosciences, after two years as scientist in the PolymerRheology and Processing Research department at DSM (Geleen, The Netherlands),and a three years postdoctoral stay with Prof. Dimitris Vlassopoulos at theFoundation for Research and Technology Hellas (Heraklion, Greece)  . 

The overall objective of her research is to understandand model at the mesoscopic level the relationship between the composition ofpolymeric samples and their rheological behavior. Her interests include thestudy of the properties of supramolecular polymer networks and the study of thenonlinear viscoelastic properties of polymer melts and solutions under shear orelongation.

She is presently coordinator of the European MSCAdoctoral Network ‘ReBond’, which aims at using vitrimers for enhancing theproperties of plastic waste.

In 2011 and in 2018, she received the Journal of RheologyPublication Award of the Society of Rheology, and in 2016, she received theArthur B. Metzner Early Career Award of the Society of Rheology. She ispresently member at large of the Society of Rheology and Associated Editor ofMacromolecules.