Energy efficient chip transience with superabsorbent polymer actuators

We demonstrate the use of super absorbent sodium polyacrylate polymers (SAPs) as actuator materials to trigger destruction of microchips upon exposure to aqueous environments. To implement the actuator the backside of a microchip is partially diced with an array of grooves. The grooves are pack filled with 25 μm SAP particles and sealed within a PDMS package containing a flow distribution network. When the chip is exposed to water the SAP particles expand in volume as much as 100-fold thus acting as distributed high-force mechanical actuators. The SAP expansion exerts tensile stress on the grooved chip sufficient to mechanically shatter it via Griffith´s mode I crack propagation. Unlike other methods which utilize hazardous materials, the new technique uses non-toxic, stable materials that are safe to store and handle, and it can be easily added to the fabrication cycle of most microchips. We present the theory, fabrication and experiments of this transience mechanism.