Switchable adhesion by chemical functionality and topography

Progress in adhesion technology over the last few decades has led to widespread replacement of mechanical fasteners with adhesive bonds. Despite the advances, it remains challenging to produce materials that are sticky on demand. In this feature article we highlight recent efforts to develop reversibly switchable adhesives, that exhibit the ability to trigger adhesion in response to an environmental change - for example, pH, solvent, temperature, mechanics, and electro/magnetic field. We review two initially separate design principles to induce switchable adhesion: (1) chemical functionality and (2) topography. Combining both approaches may lead to novel hierarchical adhesives with interesting property profiles.