Ag clusters electrochemically reduced in stearic acid Langmuir-Blodgett films and their structural characterizations

• Published in: Science China. Chemistry Vol. 40; no. 4; pp. 397 - 404
• Main Author: 张韫宏 谢兆雄 华炳增 毛秉伟 陈衍珍 李前树 田昭武
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer Nature B.V 01.08.1997
• Subjects: Bonding strength; Clusters; Diameters; Hydrogen bonding; Langmuir-Blodgett; Langmuir-Blodgett films; Molecular conformation; Raman spectra; Scanning tunneling microscopy; Self-assembly; SERS; Silver; SIM; Stearic acid; Stretching
• ISSN: 1674-7291; 1006-9291; 0253-5831; 1869-1870; 1862-2771
• DOI: 10.1007/BF02877756

Silver ions confined in the silver stearate Langmuir-Blodgett (L-B) films of 8-14 layers were elec-trochernically reduced into Ag clusters,which made the observation of well-ordered scanning tunneling microscope (STM) images of the films with molecular resolution.A hexagonal packing of the hydrophobic chains was obtained,which was superimposed on the two-dimensional Ag clusters of 2-3 nm m diameter.Furthermore,a (2×1) struc-time of the hexagonal packing was observed.It was attributed to a self-assembled structure of the hydrophilic surface of the L-B films through hydrogen bonding.The strong surface enhanced Raman scattering (SERS) effect of Ag clusters made it possible to record Raman spectra of two-layer steanc acid L-B films in the region of C-C stretching vibration frequencies The appearance of the bands at 1 128 0 and 1 100.7 cm-1,which correspond to the antisymmetric C-C stretching model of the acyl chains m the all-trans conformation and the C-C stretching model of the acyl chains in the gauche