Frost formation through super-cooled water within micron gap of galvanic coupled arrays

Frost is considered one of the key factors that negatively affects numerous daily life aspects all over the globe such as growth of crops, safety of aviation and transportation vehicles, working efficiency of air circulating systems and many others. Therefore, monitoring and early detection of frost are crucially needed to avoid such drastic effects. In this study, we used the micron gap of our newly developed galvanic coupled arrays named as moisture sensor chip (MSC) for the early detection of frost formation from super-cooled water droplets. The early frost formation was monitored via the tiny ice crystals formed on the cooled MSC surface at four different humidity levels using simultaneous electrochemical and optical microscopic detection tools. Experimental results revealed for the first time a remarkable increase in the detected galvanic current due to the condensation frosting mechanism of super-cooled water droplets via liquid transition transformation even at very low relative humidity which was believed to be responsible for de-sublimation frosting. Moreover, the super-cooled droplets formed ice bridges along their boundary domains due to the accumulation of the acquired water vapour that was evidenced by the release of the heat of solidification. These findings demonstrated that the MSC could be used as a promising platform for the early detection of frost formation considering the appropriate protective measures against its adverse effects.