title: Thermal-sensitive viscosity transition of elongated micelles induced by breaking intermolecular hydrogen bonding of amide groups.
abstract: A heat-induced viscosity transition of novel worm-like micelles of a long alkyl-chain amidoamine derivative (C18AA) bearing intermolecular hydrogen-bonding group was investigated by cryo-TEM, FT-IR, and rheological measurements. At lower temperature, C18AA forms straight elongated micelles with a length on the order of micrometers due to strong intermolecular hydrogen-bonded packing of the amide groups, although the micelles rarely entangle and have low value of zero-shear viscosity. The straight elongated micelles likely became flexible and underwent a morphological transition from straight structure to worm-like structure at a certain temperature, which caused a drastic increase in viscosity due to entanglement of the micelles. This morphological transition was caused by a defect of intermolecular hydrogen bonding between the amide groups on heating. Furthermore, addition of LiCl, which acts as hydrogen-bond breaker, also promoted the viscosity transition, leading to a lowering of the transition temperature.
authors.affiliation: Department of Industrial Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan.
authors.forename: Clara
authors.initials: C
authors.lastname: Morita
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Imura
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ogawa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kurata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kawai
mesh_terms: D000577:Amides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008823:Micelles; D015394:Molecular Structure; D010316:Particle Size; D013499:Surface Properties; D013696:Temperature; D014783:Viscosity
chemical_list: D000577:Amides; D008823:Micelles