Pulsed Evaporative Transient Thermometry on isolated microstructures

Thin film evaporation promises ultra-high heat transfer rates for thermal management, however, few measurements provide fundamental insight into the evaporation process to achieve the theoretical limits. Here, we demonstrate a new metrology technique, Pulsed Evaporative Transient Thermometry (PETT), which utilizes a series of heating pulses of an isolated microstructure, where the transient thermal response is obtained to temporally resolve heat transfer coefficients during the evaporation process. We demonstrated the approach using a model system of unoxidized and oxidized copper microwires with a temporal resolution of 0.5 seconds. Distinct heat transfer signatures were obtained from PETT combined with optical microscopy to elucidate the effect of surface morphology on the evaporation process and heat transfer coefficients. The proposed metrology technique enables increased understanding of thin film evaporation on a variety of micro and nanostructures to realize advanced thermal management solutions.