Quantitative study of molecular orientation in hemicyanine Langmuir-Blodgett films by Fourier transform infrared spectroscopy and second harmonic generation

Second-Harmonic Generation by Spontaneous Self-Poling of Supramolecular Thin Films of an Amylose−Dye Inclusion Complex

“…A similar tilt angle of chromophores was reported 4, 24,25 with LB films (on a glass substrate) made from the same hemicyanine dye, DASPC 22 , and its homologs, suggesting that the donor head group (N,N-dimethylamino) of the chromophore is bound to the glass substrate (H-donor) by H-bonding. Although the mechanistic aspect of the self-poling of the present system is unknown, it is likely that such an interface interaction 26 of the supramolecules plays a crucial role in initiating the polar orientation and influencing the subsequent dipolar alignment of the rigid-rod supramolecules, forming a self-assembly; no SHG signals were detected with the supramolecular films cast on poly(methyl methacrylate)-coated substrate, and also with poly(vinyl pyrrolidone)-DASPC 8 composite films (no inclusion) on the glass substrate.…”

Study of assembly of arachidic acid/LDHs hybrid films containing photoactive dyes

“…Takahashi et al [41] and Su et al [50] assumed that the long axis of the dye molecule is uniaxially distributed around the surface normal, and θ can be calculated through the equation [51] …”

Visualization of the Molecular Shape and the Orientational Distribution in the Langmuir−Blodgett Film of a Bent-Shaped Achiral Molecule As Studied by Surface Second-Harmonic Generation

“…As a technique to analyze the structure, SHG could be used. It is well-known that the optical SHG is a sensitive tool for studying the polar arrangement of the molecular layer. − However, it was only possible to determine the average orientation of chromophores by assuming a very sharp δ-functional distribution in C ∞ v symmetry. ,− Recently, we proposed a novel method to unambiguously determine the orientational distribution function (ODF) of molecules at interfaces with C ∞ v symmetry , and applied this method to a spin-coated polyimide with SHG-active side chains. Application of this technique to the surfaces with in-plane anisotropy such as rubbed films for aligning liquid crystal molecules was also made using a modified maximum entropy method .…”