Material transfer controlled by elastomeric layer thickness†
Transferring material components across substrates through the control of interfacial adhesion is important for electronics, biology and other fabrication processes. Here we show a transfer mechanism which controls adhesive force through the thickness of supported elastomeric substrates. This is experimentally demonstrated by transferring millimeter and centimeter scale wafers to progressively thinner substrates without any specific actuation, chemical treatment, or surface topography. We extend this methodology by selectively transferring objects with sub-surface patterns and demonstrate how thickness control can enable roll-to-roll material transfer processes. These experiments are supported by a theoretical model which demonstrates how this mechanism is governed by the geometric confinement of the interface, where adhesive force is increased by decreasing the thickness of the elastomeric substrate relative to the lateral dimension of the transferred object. This simple, glueless approach allows for the precise control of adhesive force capacity as well as a mechanism to greatly enhance adhesive strength.