Power density threshold for switching off the tack adhesion of colloidal nanocomposites

Abstract

Colloidal nanocomposite adhesives are made by blending soft adhesive particles with hard nanoparticles (NPs) that sit at the particle boundaries to create a percolating phase. When the nanocomposite is heated with infrared (IR) radiation, the NPs sinter together to create a rigid structure that hardens the composite and thereby switches off the tack adhesion. It is discovered that the IR power density of an irradiation for 20 s must exceed a threshold value of 1.07 W cm-2 before the tack is switched off. At lower power densities, an analysis of the sintering of the NPs shows that there is not sufficient time to link them together into a rigid structure. These results reveal that the switching of colloidal nanocomposite adhesives can be easily controlled through the IR power density and the time of the exposure. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.