This paper describes a microfluidic instrument that produces drops of supercooled water suspended in a moving stream of liquid fluorocarbon, and measures the temperatures at which ice nucleates in the drops. A microfluidic chip containing a monodisperse drop generator and a straight channel with 38 embedded resistance thermometers was placed in contact with a seven-zone temperature-control plate and imaged under a microscope with a high-speed camera. This instrument can record the freezing temperatures of tens of thousands of drops within minutes, with an accuracy of 0.4 degrees C. The ice-nucleation temperatures in approximately 80-microm drops were reported for the freezing of 37 061 drops of pure water, and of 8898 drops of water seeded with silver iodide. Nucleation of ice in pure water was homogenous and occurred at temperatures between -36 and -37.8 degrees C, while water containing silver iodide froze between -10 and -19 degrees C. The instrument recorded the largest sets of individual freezing temperatures (37 061), had the fastest data acquisition rate (75 measurements/s), and the best optical (3 microm) and temporal (70 micros) resolutions among instruments designed to study nucleation of ice. The dendritic growth of ice in 150-microm drops of supercooled water at -35 degrees C was observed and imaged at a rate of 16 000 frames/s.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1039/b906198c | DOI Listing |
J Food Sci
January 2025
Department of Human Nutrition, Food, and Animal Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA.
Freezing extends the shelf life of foods but often leads to structural damage due to ice crystal formation, negatively impacting quality attributes. Oscillating magnetic field (OMF)-assisted supercooling has emerged as a potential technique to overcome these limitations by inhibiting ice nucleation and maintaining foods in a supercooled state. Despite its potential, the effectiveness and underlying mechanisms of OMF-assisted supercooling remain subjects of debate.
View Article and Find Full Text PDFFood Chem
January 2025
Key Laboratory of Tropical Fruits and Vegetables Quality and Safety for State Market Regulation, Institute of Food Testing, Hainan Academy of Inspection and Testing, Haikou 570314, China. Electronic address:
Ozone (O) is an effective agent for post-harvest fruit preservation against diverse microorganisms. In this study, a cost-effective ozone micro-nano bubbles ice (O-MNBI) was prepared, characterized, and subsequently used to precool litchi. The optimal protocols for O-MNBI production were as follows: water (2 °C, pH = 7) was pumped into a micro-nano O bubble generator for 10 min aeration treatment.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Key Laboratory of Green, Low-carbon and Efficient Development of Marine Fishery Resources, Hangzhou 310014, China; National R&D Branch Center for Pelagic Aquatic Products Processing (Hangzhou), Hangzhou 310014, China. Electronic address:
Slurry ice preparation experiences considerable supercooling, which can be mitigated by nano-nucleating agents. A nano-nucleating agent (CH/PE-TP NPs) was prepared by ultrasonication-assistant self-assembly of chitosan (CH) and pectin (PE), encapsulated with tea polyphenols (TP). Ultrasonication for 10 min downsized self-assembled aggregates from 5.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Université Claude Bernard Lyon 1, INSA Lyon, Université Jean Monnet, CNRS, UMR 5223, Ingénierie des Matériaux Polymères, F-69621 Villeurbanne Cédex, France.
Supercooling allows for retarding water crystallization toward negative Celsius temperatures. Previous findings of CO molecules shifting into bicarbonate species upon freezing, the latter which naturally adsorb on hydrophobic interfaces, are put in perspective here to interpret earlier published data. Since it has been shown that ice nucleation is unlikely on negatively charged surfaces, I propose that bicarbonates adsorb on most solid particles present in water that act as nucleators, thus retarding freezing and enhancing supercooling.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Manufacture Science and Engineering, Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, People's Republic of China.
Ice accretion caused by freezing rain or snowstorms is a common phenomenon in cold climates that seriously threatens the safety and reliability of telecommunication lines and other overhead networks. Various anti-icing strategies have been demonstrated through surface engineering to delay ice formation. However, existing anti-icing surfaces still encounter several challenges; for example, surfaces are prone to ice-pinning formation due to the impact of supercooled droplets, which leads to a loss of anti-icing effectiveness.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!