Preparation and characterization of Langmuir and Langmuir-Blodgett films from a nitrile-terminated tolan

作者：Pera Gorka; Villares Ana; Lopez Maria Carmen; Cea Pilar^*; Lydon Donocadh P; Low Paul J

来源：Chemistry of Materials, 2007, 19(4): 857-864.

DOI：10.1021/cm062524p

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 surface pressure and surface potential isotherms together with Brewster angle microscopy being used to map the different phases of the tolan monolayer at the air-water interface. The Langmuir films have been characterized by UV-vis spectroscopy, with quantitative analysis of the reflection spectra supporting an organizational model in which compression of the film leads to change in the tilt angle of the tolan molecules from an initial value of ca. 35 degrees to one of ca. 60 degrees 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 a chloroform solution of the nitrile tolan indicates that two-dimensional H-aggregates are formed at the air-water interface. These structures represent a minimum free-energy conformation for the system, as they are observed even before the compression process starts. The monolayers are transferred undisturbed onto solid substrates, with atomic force microscopy revealing well-ordered films without three-dimensional defects.

• 出版日期2007-2-20
• 单位中国地震局