Preparation and Characterization of Langmuir and Langmuir-Blodgett Films from a Nitrile-Terminated Tolan

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• 作者：Gorka Pera ; Ana Villares ; Marí ; a Carmen Ló ; pez ; Pilar Cea ; Donocadh P. Lydon ; Paul J. Low
• 刊名：Chemistry of Materials
• 出版年：2007
• 出版时间：February 20, 2007
• 年：2007
• 卷：19
• 期：4
• 页码：857 - 864
• 全文大小：538K
• 年卷期：v.19,no.4(February 20, 2007)
• ISSN：1520-5002

文摘

Langmuir and Langmuir-Blodgett films of a nitrile-terminated tolan, namely 4-[4'-decyloxyphenylethynyl]benzonitrile, have been fabricated and characterized at various surface pressures, with surfacepressure and surface potential isotherms together with Brewster angle microscopy being used to map thedifferent phases of the tolan monolayer at the air-water interface. The Langmuir films have beencharacterized by UV-vis spectroscopy, with quantitative analysis of the reflection spectra supporting anorganizational model in which compression of the film leads to change in the tilt angle of the tolanmolecules from an initial value of ca. 35 to one of ca. 60 before collapse of the monolayer. Moreover,a blue shift in the reflection spectrum of the Langmuir film of 30 nm with respect to the spectrum of achloroform solution of the nitrile tolan indicates that two-dimensional H-aggregates are formed at theair-water interface. These structures represent a minimum free-energy conformation for the system, asthey are observed even before the compression process starts. The monolayers are transferred undisturbedonto solid substrates, with atomic force microscopy revealing well-ordered films without three-dimensionaldefects.