title: Aqueous foams stabilized by temperature-sensitive hairy polymer particles.
abstract: Submicrometer-sized polystyrene (PS) particles carrying poly[2-(diethylamino)ethyl methacrylate] (PDEA) hairs (PDEA-PS particles) were synthesized by free radical dispersion polymerization. The hydrophilicity-hydrophobicity balance of the PDEA could be tuned by varying the temperature at near neutral pH (a lower critical solution temperature of PDEA at pH 6.86, 41 °C) and therefore these sterically-stabilized particles acted as temperature-sensitive stabilizers for aqueous foams. At 25 °C, where the PDEA hairs were hydrated and PDEA-PS particles were colloidally stable in aqueous media, foams were formed which coalesced with time and the size of the bubble increased. At 40 and 45 °C, where the PDEA hairs were partially non-hydrated and PDEA-PS particles were close to flocculation or weakly flocculated, foams were formed and bubble coalescence and size increase speeds were slower than those observed at 25 °C. At and above 50 °C, where the PDEA hairs were non-hydrated and PDEA-PS particles were heavily flocculated in aqueous media, the more stable cream-like foams whose volume was almost the same for 1 week were formed. Scanning electron microscopy studies indicated that the particles mainly adsorbed at the air-water interface as monolayers at 25 °C and as multilayers at and above 40 °C. The foam stability and structure could be controlled by changing the temperature.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology, 5-16-1, Omiya, Asahi-ku, Osaka 535-8585, Japan. syuji.fujii@oit.ac.jp.
authors.forename: S
authors.initials: S
authors.lastname: Nakayama
authors.affiliation: Department of Applied Chemistry, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yusa
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology, 5-16-1, Omiya, Asahi-ku, Osaka 535-8585, Japan. syuji.fujii@oit.ac.jp and Nanomaterials Microdevices Research Center, Osaka Institute of Technology, 5-16-1, Omiya, Asahi-ku, Osaka 535-8585, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology, 5-16-1, Omiya, Asahi-ku, Osaka 535-8585, Japan. syuji.fujii@oit.ac.jp.
authors.forename: S
authors.initials: S
authors.lastname: Fujii