Toughening and asymmetry in peeling of heterogeneous adhesives
Laurent Ponson (Institut Jean Le Rond d'Alembert Université Pierre et Marie Curie), Shuman Xia (Georgia Tech), Kaushik Bhattacharya (California Institute of Technology), G. Ravichandran (Caltech)
Eringen Medal Symposium in honor of G. Ravichandran
Tue 2:40 - 4:00
Salomon 001
Thin film adhesives are ubiquitous in our daily life, and they have become increasingly important in various applications such as packaging and coating. Despite their apparent simplicity, these systems can reveal a wide range of behaviors resulting from the complex interplay between the deformations of the elastic thin film and the dissipative processes of failure at the substrate-thin film interface. Here, we show how to take advantage of this complexity by designing adhesives with specific periodic arrangements of pinning sites - corresponding to zones of larger adhesion energy – that give rise to high variations of the adhesive strength with the peeling direction and its sense [1,2]. To go beyond strength anisotropy, we investigate systems with heterogeneous elastic properties. We show how arrangements of stiff and compliant stripes on the thin film can produce a dramatic increase of their effective resistance by controlling the rate of elastic energy released by the elastic film as peeled from a substrate [3]. Through these experimental examples and their theoretical interpretation, we will illustrate how spatial variations of material properties, by controlling their deformation during the process of peeling, can give rise to new and improved adhesion properties. [1] S. M. Xia, L. Ponson, G. Ravichandran and K. Bhatacharya, 'Adhesive tape with adhesion enhancement and directionality by material, structural and adhesive heterogeneity’, International patent, PCT/US10/62110 (2011). [2] S. M. Xia, L. Ponson, G. Ravichandran and K. Bhatacharya, 'Toughening and asymmetry in peeling of heterogeneous adhesives', Phys. Rev. Lett. 108, 196101 (2012). [3] S. M. Xia, L. Ponson, G. Ravichandran and K. Bhatacharya, 'Adhesion of heterogeneous thin films: I Elastic heterogeneity', J. Mech. Phys. Sol. 61, 838-851 (2013).