Long-term adhesion durability revealed through a rheological paradigm.

Abstract

The question of how long an object can adhere to a surface has intrigued scientists for centuries. Traditional studies focus on rapid crack-propagation detachment and account only for short-term adhesion governed by interfacial-viscoelastic dissipation, failing to explain long-term phenomena like sudden detachment after prolonged adherence and to predict corresponding adhesion lifetimes. Here, we investigate the long-term adhesion through a rheological paradigm using both theory and experiment. By considering both the bulk rheology and interfacial viscoelasticity mechanisms, we show that long-term adhesion durability is governed by the competition between them. This understanding leads to accurate lifetime predictions, which we validate through experiments. In addition, our study reveals a previously undocumented, counterintuitive phenomenon unique to long-term adhesion: the expansion of the contact area under tensile forces, in contrast to short-term adhesion in which the contact area always shrinks during detachment. This research fills a critical gap in adhesion physics.