Heat-stimulated lifetime-controllable encapsulation for transient electronics

Abstract

Transient electronic systems have attracted considerable attention because of their ability to degrade after a specific period. The development of flexible encapsulant materials with hydrophobic and stimulus-responsive characteristics is necessary for the operation and lifetime control of transient electronics. Although several stimulus-responsive encapsulating materials have been developed over the past few years, harsh stimuli and degradation products limit the application of encapsulants. In this study, composite films of biodegradable polymers (e.g., polycaprolactone) and fatty acids (e.g., lauric acid), which are biodegradable and biocompatible, were used as encapsulants for transient electronics. Composite films were formed using a simple solvent-casting technique. The water permeation and stimulus responsiveness of the composite films were studied under biological conditions, in which the lifetime of the encapsulated electronic component was controlled by manipulating the film composition and applying heat for a short period. The development of composite films of polymers and fatty acids facilitated the precise control of the lifetime of the composite material, that is, the dissolution rate. Moreover, the application of the composite material as an encapsulant achieved facile lifetime control of transient electronic devices, thereby significantly accelerating the commercialization of transient electronics.