Witnessing a discrete microdroplet freezing event real-time electrochemical monitoring of solution temperature.

Temperature monitoring has immediate relevance to many areas of research, from atmospheric environmental studies to biological sample and food preservation to chemical reactions. Here, we use a triple-barrel electrode to provide temperature readouts in bulk solution and microdroplets, as well as electrochemically monitor freezing events in a microdroplet. Using this method, we are able to identify distinct characteristics of a freezing aqueous droplet (supercooling, ice formation beginning and end, temperature change, and thawing) with greater temporal resolution than a standard thermocouple and without the use of microscopy.

The gas|liquid interface eclipses the liquid|liquid interface for glucose oxidase rate acceleration in microdroplets.

The curious chemistry observed in microdroplets has captivated chemists in recent years and has led to an investigation into their ability to drive seemingly impossible chemistries. One particularly interesting capability of these microdroplets is their ability to accelerate reactions by several orders of magnitude. While there have been many investigations into which reactions can be accelerated by confinement within microdroplets, no study has directly compared reaction acceleration at the liquid|liquid and gas|liquid interfaces.