title: Analysis of supercooling activities of surfactants.
abstract: Supercooling-promoting activities (SCAs) of 25 kinds of surfactants including non-ionic, anionic, cationic and amphoteric types were examined in solutions (buffered Milli-Q water, BMQW) containing the ice nucleation bacterium (INB) Erwinia ananas, silver iodide (AgI) or BMQW alone, which unintentionally contained unidentified ice nucleators, by a droplet freezing assay. Most of the surfactants exhibited SCA in solutions containing AgI but not in solutions containing the INB E. ananas or BMQW alone. SCAs of many surfactants in solutions containing AgI were very high compared with those of previously reported supercooling-promoting substances. Cationic surfactants, hexadecyltrimethylammonium bromide (C16TAB) and hexadecyltrimethylammonium chloride (C16TAC), at concentrations of 0.01% (w/v) exhibited SCA of 11.8 °C, which is the highest SCA so far reported. These surfactants also showed high SCAs at very low concentrations in solutions containing AgI. C16TAB exhibited SCA of 5.7 °C at a concentration of 0.0005% (w/v).
authors.affiliation: Research Faculty and Graduate School of Agriculture, Hokkaido University, Sapporo 060-0805, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Kuwabara
authors.affiliation: New Product Development Office, COSMO-OIL LUBRICANTS Co., Ltd., 1134-2 Gongendo, Saitama 340-0193, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Terauchi
authors.affiliation: New Product Development Office, COSMO-OIL LUBRICANTS Co., Ltd., 1134-2 Gongendo, Saitama 340-0193, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tochigi
authors.affiliation: New Product Development Office, COSMO-OIL LUBRICANTS Co., Ltd., 1134-2 Gongendo, Saitama 340-0193, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Takaoka
authors.affiliation: Research Faculty and Graduate School of Agriculture, Hokkaido University, Sapporo 060-0805, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Arakawa
authors.affiliation: Research Faculty and Graduate School of Agriculture, Hokkaido University, Sapporo 060-0805, Japan. Electronic address: sfuji@for.agr.hokudai.ac.jp.
authors.forename: Seizo
authors.initials: S
authors.lastname: Fujikawa
mesh_terms: D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D003080:Cold Temperature; D003460:Crystallization; D004885:Erwinia; D005615:Freezing; D007053:Ice; D007454:Iodides / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D018030:Silver Compounds / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry* / Q000502:physiology*
chemical_list: D002593:Cetrimonium Compounds; D007053:Ice; D007454:Iodides; D000644:Quaternary Ammonium Compounds; D018030:Silver Compounds; D013501:Surface-Active Agents; C514921:hexadecyltrimethylammoniumchloride; D014867:Water; C030584:silver iodide; D000077286:Cetrimonium
keywords: Antifreeze proteins; Freezing of water; Heterogeneous ice nucleation; Supercooling; Surfactants