This title appears in the Scientific Report : 2013 

Adhesion: role of bulk viscoelasticity and surface roughness
Lorenz, B (Corresponding author)
Krick, B A / Mulakaluri, N. / Smolyakova, M. / Dieluweit, S / Sawyer, W G / Persson, Bo
Quanten-Theorie der Materialien; PGI-1
Biomechanik; ICS-7
Quanten-Theorie der Materialien; IAS-1
Journal of physics / Condensed matter, 25 (2013) 22, S. 225004
Bristol IOP Publ. 2013
10.1088/0953-8984/25/22/225004
Journal Article
Exploratory materials and phenomena
Please use the identifier: http://dx.doi.org/10.1088/0953-8984/25/22/225004 in citations.
We study the adhesion between smooth polydimethylsiloxane (PDMS) rubber balls and smooth and rough poly(methyl methacrylate) (PMMA) surfaces, and between smooth silicon nitride balls and smooth PDMS surfaces. From the measured viscoelastic modulus of the PDMS rubber we calculate the viscoelastic contribution to the crack-opening propagation energy γeff(v,T) for a wide range of crack tip velocities v and for several temperatures T. The Johnson–Kendall–Roberts (JKR) contact mechanics theory is used to analyze the ball pull-off force data, and γeff(v,T) is obtained for smooth and rough surfaces. We conclude that γeff(v,T) has contributions of similar magnitude from both the bulk viscoelastic energy dissipation close to the crack tip, and from the bond-breaking process at the crack tip. The pull-off force on the rough surfaces is strongly reduced compared to that of the flat surface, which we attribute mainly to the decrease in the area of contact on the rough surfaces.