Active control of supercooling degree using surfactant (In system with solid–liquid interface)

• Controlling average supercooling degree by addition of surfactant was possible.
• The peculiar concentration which agreed with critical micelle concentration existed.
• Average supercooling degrees below and over peculiar concentration were different.
• Tendencies of average supercooling degree didn't vary regardless of surfactant type.
• Factors which might govern average supercooling degrees were clarified.

Supercooling reduces the COP of ice formation systems. So, control of supercooling dissolution is useful and would bring numerous benefits. In a previous report, the authors conducted an experiment to control supercooling dissolution in a mixture with a hydrophilic surfactant and water in a glass test tube which had the liquid–gas(air) interface, and it was possible to actively control average supercooling degree by varying the surfactant concentrations. The average supercooling degrees' tendencies below and over a critical micelle concentration, calculated based on the variation in surface tensions, were quite different. However, since the critical micelle concentration is a physical quantity concerned only with liquid–gas interface, it is essential to investigate phenomena in a system with a solid–liquid interface. So, in a syringe with a system having only a solid–liquid interface, possibility of active control of average supercooling degree by variation in surfactant concentrations is investigated.