Molecular insight in fracture of soft materials
Event details
| Date | 25.03.2019 |
| Hour | 13:15 › 14:15 |
| Speaker | Prof. Costantin Creton, Soft Matter Science and Engineering Laboratory, ESPCI ParisTech |
| Location | |
| Category | Conferences - Seminars |
Fracture of soft materials is a complex process coupling non linear mechanics and statistical physics[1]. Because of the large deformations involved before a crack propagates, molecular damage typically occurs in the bulk of the material and not only in the fracture plane[2]. This is particularly true for tough soft materials where bulk energy dissipation mechanisms such as sacrificial bonds are introduced by design. Until recently the detection of damage ahead of a crack was limited to the detection of crystallization or cavitation, detectable by wide or small angle X-ray scattering or optical visualisation, but molecular bond scission was not directly detectable. However organic chemists have now developed several molecules that respond to applied forces or bond scission by changing their light absorption or emission properties[3] providing novel opportunities for materials scientists to gain insight in molecular processes occurring during mechanical loading.
We have incorporated mechanosensitive molecules as crosslinkers in model transparent soft polymer networks containing sacrificial bonds and used them to detect and map stresses and molecular damages before and during crack propagation. Spyropyran can be used to detect stresses in real time and to distinguish loaded regions from unloaded ones. Dioxetane based molecules emit light when they break and can be used to obtain time resolved information on the bond scission process and pi-extended anthracene can be used to obtain high resolution spatial information. A combination of several techniques is needed to investigate the temporal and spatial process of damage in soft and tough materials in order to develop proper molecular models and guide the design of novel materials. We will focus on the mechanisms occurring during crack propagation and necking of multiple network elastomers where a stiff and highly stretched network is embedded in a more extensible matrix{Millereau, 2018 #5305} .
References
[1] C. Creton, M. Ciccotti, Rep Prog Phys 2016, 79, 046601; C. Creton, Macromolecules 2017, 50, 8297.
[2] E. Ducrot, Y. Chen, M. Bulters, R. P. Sijbesma, C. Creton, Science 2014, 344, 186.
[3] R. Gostl, R. P. Sijbesma, Chemical Science 2016, 7, 370; Y. Chen, A. J. H. Spiering, KarthikeyanS, G. W. M. Peters, E. W. Meijer, R. P. Sijbesma, Nature Chemistry 2012, 4, 559; D. A. Davis, A. Hamilton, J. Yang, L. D. Cremar, D. Van Gough, S. L. Potisek, M. T. Ong, P. V. Braun, T. J. Martinez, S. R. White, J. S. Moore, N. R. Sottos, Nature 2009, 459, 68.
Bio: 1985 : BS, Materials Science & Engineering, EPFL , Switzerland
1991 : Ph. D. Cornell University, USA
1992-1993 : Research Fellow, IBM Almaden, USA
1994-2001: CNRS Researcher (Assistant Professor) at the ESPCI, Laboratory of Physical Chemistry of Polymers, Paris, France
2001- : CNRS Research Director (Professor) at the ESPCI, Laboratory of Physical Chemistry of Polymers, Paris, France
We have incorporated mechanosensitive molecules as crosslinkers in model transparent soft polymer networks containing sacrificial bonds and used them to detect and map stresses and molecular damages before and during crack propagation. Spyropyran can be used to detect stresses in real time and to distinguish loaded regions from unloaded ones. Dioxetane based molecules emit light when they break and can be used to obtain time resolved information on the bond scission process and pi-extended anthracene can be used to obtain high resolution spatial information. A combination of several techniques is needed to investigate the temporal and spatial process of damage in soft and tough materials in order to develop proper molecular models and guide the design of novel materials. We will focus on the mechanisms occurring during crack propagation and necking of multiple network elastomers where a stiff and highly stretched network is embedded in a more extensible matrix{Millereau, 2018 #5305} .
References
[1] C. Creton, M. Ciccotti, Rep Prog Phys 2016, 79, 046601; C. Creton, Macromolecules 2017, 50, 8297.
[2] E. Ducrot, Y. Chen, M. Bulters, R. P. Sijbesma, C. Creton, Science 2014, 344, 186.
[3] R. Gostl, R. P. Sijbesma, Chemical Science 2016, 7, 370; Y. Chen, A. J. H. Spiering, KarthikeyanS, G. W. M. Peters, E. W. Meijer, R. P. Sijbesma, Nature Chemistry 2012, 4, 559; D. A. Davis, A. Hamilton, J. Yang, L. D. Cremar, D. Van Gough, S. L. Potisek, M. T. Ong, P. V. Braun, T. J. Martinez, S. R. White, J. S. Moore, N. R. Sottos, Nature 2009, 459, 68.
Bio: 1985 : BS, Materials Science & Engineering, EPFL , Switzerland
1991 : Ph. D. Cornell University, USA
1992-1993 : Research Fellow, IBM Almaden, USA
1994-2001: CNRS Researcher (Assistant Professor) at the ESPCI, Laboratory of Physical Chemistry of Polymers, Paris, France
2001- : CNRS Research Director (Professor) at the ESPCI, Laboratory of Physical Chemistry of Polymers, Paris, France
Links
Practical information
- General public
- Free
Organizer
- Esther Amstad & Vaso Tileli
Contact
- Esther Amstad & Vaso Tileli