Supercooled micro flow in microchannels was demonstrated. In order to clarify fundamental properties of the supercooling state in microchannels, freezing temperature was measured in the microchannels having widths ranging from 70 μm to 300 μm. The freezing temperature decreased with decreasing width of the microchannel when the microchannel wall was chemically modified with octadecylsilane group. The lowest freezing temperature was observed as -28°C for water in the 70 μm wide microchannel. By contrast, the freezing temperature was -15°C and did not depend on width when a microchannel with a bare glass surface was used. Next, the freezing point was measured with flow rates ranging from 0.1 to 2.0 μl min-1 and no dependence on flow rate was observed. Then, the supercooled micro flow was applied to an asymmetric reaction in micro two-phase flow of aqueous and CH2Cl2 phases. As expected from thermodynamic prediction, enantiomeric selectivity increased in the supercooled state of water.
ASJC Scopus subject areas
- Biomedical Engineering