title: Effects of hydrogen bonding on the monolayer properties of amphiphilic double-decker-shaped polyhedral silsesquioxanes.
abstract: "Core-corona" type amphiphiles, which comprise double-decker-shaped POSSs (DDSQs) as the core and two or four di(ethylene glycol) (DEG) units as the coronae, have recently been reported to form a stable monolayer at the air-water interface. In this paper, another core-corona amphiphile, 2DEGNH-DDSQ, which has a urethane group at the end of the coronae, was synthesized to elucidate the effects of hydrogen bonding on monolayer properties. The surface pressure-area isotherm and Brewster angle microscopy revealed that 2DEGNH-DDSQ initially formed rodlike assemblies. They subsequently coalescence to form a uniform monolayer with compression. Actually, 2DEGNH-DDSQs are well ordered in the rodlike assembly because of the strong hydrogen bonds among the urethane groups, as confirmed by FT-IR spectra. Although the monolayer was not transferred onto a solid substrate, mixing of 2DEGNH-DDSQ with 2DEG-DDSQ, which has already been reported to form a liquidlike monolayer, overcame this problem. The 1:1 molar mixture of 2DEGNH-DDSQ and 2DEG-DDSQ forms a uniform liquidlike monolayer. The mixed monolayer was transferred onto a solid substrate as a Z-type Langmuir-Blodgett film. Atomic force microscopic (AFM) images of the mixed-bilayer film showed a uniform surface with root-mean-square surface roughness of 0.21 nm. The intermolecular hydrogen bonds between the urethane groups in 2DEGNH-DDSQ and the hydroxyl groups in 2DEG-DDSQ improve the monolayer properties, which enable successful transfer of the LB film.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Asuman C
authors.initials: AC
authors.lastname: Kucuk
authors.forename: Jun
authors.initials: J
authors.lastname: Matsui
authors.forename: Tokuji
authors.initials: T
authors.lastname: Miyashita
mesh_terms: D000388:Air; D005026:Ethylene Glycols / Q000737:chemistry; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D017646:Organosilicon Compounds / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D005026:Ethylene Glycols; D017646:Organosilicon Compounds; D011108:Polymers; D014867:Water; C013484:diethylene glycol