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【材苑揽胜】Molecular insight in the fracture mechanisms of soft networks

发布时间:2018-09-24 字体:[增加 减小]
报告题目:Molecular insight in the fracture mechanisms of soft networks

报告人: Prof. Costantino Creton, (Laboratory of Soft Matter Science and Engineering, ESPCI, Paris, France)

时间:2018/9/2714:30 逸夫楼10楼报告厅


 

 


报告摘要:In fracture of soft materials, the internal damage (bond scission or plastic deformation of crystals or clusters) preceding crack propagation is very difficult to detect, because it is typically not readily visible optically and is not detectable by electron microscopy techniques. This has hampered physically based fracture models from being tested experimentally. Recently mechanochemistry has provided a powerful tool to do so1-3. Specific molecules have been developed that react to the application of a mechanical force by changing their light absorption when the applied force on the bond exceeds a critical value (spyropyran -> merocyanine), by emitting light upon bond scission (bis-adamantane dioxetane molecules) or by becoming fluorescent upon bond scission (pi-extended anthracene). If these molecules are incorporated into soft networks (generally as a dilute crosslinker) they can act as detectors of local bond scission or of a high stress region and be used to map damage zones4-5. In this work we will specifically discuss the incorporation of mechanosensitive molecules into multiple network elastomers that mimic well the behavior of soft filled materials. These marker molecules can be used to mark sacrificial bonds inside the material and providing therefore a signal of when the sacrificial bonds fails therefore imaging in 3D with confocal microscopy the locus of the damaged zone ahead of a crack.


报告人简介:

Costantino obtained him BS degree from EPFL in Switzerland, and his PhD in Cornell University (1991). He was a research fellow at IBM from 1992-1993, and then joined ESPCI in 1994, firstly as a CNRS researcher and then research director.  His research focuses on the relationship between molecular network structure of polymers, mesostructure and macroscopic mechanical properties of polymers above their Tg. The work spreads from the design of soft polymer network architectures ranging from conventional rubbers, to softer self-adhesive materials all the way to very soft swollen hydrogels. He has published over170 papers in high profile journals, including Nature, Science, PNAS, PRL, Advanced Materials, Reports on Progress in Physics; more than 100 conference proceedings and has given more than 80 invited and plenary lectures at international conferences.  He has received several prizes and awards including the Prix Dédale of the French Adhesion Society in 2007, the Wake Medal from the UK Society of Adhesion and Adhesives in 2011, and the Adhesion Society’s prize for Excellence in Adhesion Science in 2013. He was also elected as a fellow of the American Physical Society in 2013.

Email: Costantino.creton@espci.fr

Web: http://ccreton.simm.espci.fr/

 

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