ESR and ENDOR Studies of Functional LB Films

Abstract

Abstract Role of ESR and ENDOR spectroscopies in the characterization of functional LB films is discussed. Two illustrative examples are shown. In the first case, the detailed study of in-plane molecular orientation is discussed from the analysis of the ESR and ENDOR spectra of the stable radicals detected in LB films of a merocyanine dye. By identifying a nitrogen hyperfine structure, computer simulation of the ESR spectra yields a characteristic orientation of radicals with respect to the dipping direction of the substrate. The results strongly suggest a flow orientation of J-aggregates from which radicals may originate. The observed orientation is well described by the recent theory of flow orientation. In the second case, study of the temperature dependence of ESR signal, in particular the spin susceptibility, is shown to provide the microscopic evidence for the development of columnar structures in conducting LB films composed of amphiphilic charge-transfer complexes.