Optical Properties of Fluorinated Bent-Core Liquid Crystals Confined in Anodic Alumina Nanotubes

Abstract

In the present work, oxalic amorphous porous anodic alumina membranes with highly ordered porous arrays and average nanometric porous dimensions of 70 nm in diameter and 17 microns in depth (nanotubes) were prepared and successfully used as host matrix for fluorinated bent-core liquid crystals. Atomic force microscopy studies were performed on the organic-inorganic hybrid samples in order to explore surface morphology and optimal insertion of these liquid crystalline (LC)-compounds into this environment. The quadratic nonlinear optical (NLO) and spectroscopic properties of the implemented mesogen with the nanotube-like confinement were systematically studied in order to evaluate its optical performance. Bent core molecules have shown interesting optical properties which have not yet been intensively investigated in solid-state hybrid structures. Hence, the obtained hybrid composites represent a promising field of investigation in the route to functional bent-core based materials, where different bent-core mesomorphic structures can be obtained and are of interest for new and improved applications in nanotechnology.

Keywords:

• Bent-core molecules
• hybrid materials
• liquid crystals
• nanostructures
• optical properties
• porous anodic alumina

Acknowledgments

One of the authors (O. G. Morales-Saavedra) acknowledges financial support from the DAAD academic organization (Germany) and to the PAPIIT-DGAPA-UNAM (grant IN-IN115508).

Notes

¹A slightly PFB loaded, partially transparent toluene solution was prepared in order to assure that the Beer–Lambert law applies in UV-Vis spectral measurements.