title: Supramolecular architecture in Langmuir and Langmuir-Blodgett films incorporating a chiral azobenzene.
abstract: This article describes the synthesis and fabrication of Langmuir and Langmuir-Blodgett (LB) films incorporating a chiral azobenzene derivative, namely, ( S)-4- sec-butyloxy-4'-[5''-(methyloxycarbonyl)pentyl-1''-oxy]azobenzene, abbreviated as AZO-C4(S). Appropriate conditions for the fabrication of monolayers of AZO-C4(S) at the air-water interface have been established, and the resulting Langmuir films have been characterized by a combination of surface pressure and surface potential versus area per molecule isotherms, Brewster angle microscopy, and UV-vis reflection spectroscopy. The results indicate the formation of an ordered trilayer at the air-water interface with UV-vis reflection spectroscopy showing a new supramolecular architecture for multilayered films as well as the formation of J aggregates. Films were transferred onto solid substrates, with AFM revealing well-ordered multilayered films without 3D defects. Infrared and UV-vis absorption spectroscopy indicate that the supramolecular architecture may be favored by the formation of H bonds between acid groups in neighboring layers and pi-pi intermolecular interactions. Circular dichroism spectra reveal chiro-optical activity in multilayered LB films.
authors.affiliation: Departamento de Quimica Organica-Quimica Fisica, Facultad de Ciencias, Universidad de Zaragoza, Plaza de San Francisco, Ciudad Universitaria, 50009 Zaragoza, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Haro
authors.forename: Jesús
authors.initials: J
authors.lastname: del Barrio
authors.forename: Ana
authors.initials: A
authors.lastname: Villares
authors.forename: Luis
authors.initials: L
authors.lastname: Oriol
authors.forename: Pilar
authors.initials: P
authors.lastname: Cea
authors.forename: M Carmen
authors.initials: MC
authors.lastname: López