ABSTRACT

A fine control of viscoelasticity is a requisite in many applications of soft materials and in particular for pressure-sensitive-adhesives and to improve fracture resistance. We will discuss two examples where dissipative processes and non-linear elasticity are important to control properties. In soft PSA the combination of a very viscoelastic behavior at small strains and a marked strain hardening at large strain is essential but poses important challenges in the modeling of such materials, which we will address. fracture of hydrogels can be significantly enhanced by the introduction of labile chemical bonds able to break at lower macroscopic stresses than covalent bonds and dissipate energy at the crack tip. We will discuss the example of soft hydrogels reinforced with silica particles able to attache and detach from the polymer chains upon deformation.

ABOUT THE SPEAKER

Costantino Creton graduated in Materials Science from the Ecole Polytechnique Férale de Lausanne (Switzerland) in 1985. He then moved on to the Materials Science and Engineering Department of Cornell University (USA) where he obtained his Ph.D in 1991. After a post-doc at the IBM Almaden Research Center (USA), he joined the Laboratoire de Physico-Chimie Structurale et Macromolélaire of the ESPCI ParisTech first as a post-doctoral associate in 1993 and, since 1994 as a C.N.R.S. permanent researcher. He was promoted CNRS research director (equivalent to Professor) in 2001 in the Laboratoire de PhysicoChimie des Polymès et Milieux Dispersé Since 2009, he is coordinating the research activities of the Soft Polymer Networks research group of the laboratory. he is also in charge of the International Relations of ESPCI ParisTech. He has published more than 100 articles in peer-reviewed journals, nine book chapters, more than 100 conference proceedings and has given more than 50 invited and plenary lectures at international conferences. His research interests focus on the mechanical properties of polymers at interfaces and on deformation and fracture of soft polymer networks. More information can be found in the research pages and in the website of the laboratory. He has received the best paper award from the Adhesion Society in 2000 , the Polymer Prize from the French Polymer Group in 2002, the Prix Déle of the French Adhesion Society in 2007, the Journal of Polymer Science Polymer Physics award in 2008 and the Wake Medal from the UK Society of Adhesion and Adhesives in 2011.