Facile Preparation of Self-Assembled Layered Double Hydroxide-Based Composite Dye Films As New Chemical Gas Sensors

The useful functionalization and self-assembly of two-dimensional layered materials like hydrotalcite (LDH) are critical for the wide application of nanomaterials. In this work, some self-assembled Langmuir films of ion-exchanged LDH and dyes with different molecular structures were prepared by the Langmuir-Blodgett (LB) technique. The aggregation states of used dye molecules on the surface of the obtained membrane and the structures/properties of the membrane were studied. The hydroxyethyl sulfonate-inserted LDH (LDH-Ise) nanosheets were able to induce the dye formation of highly ordered H-and/or J-aggregate structures. Surface-enhanced Raman scattering (SERS) spectroscopy results demonstrated the uniformity and repeatability of the film. Interestingly, the good acid-base gas response characteristics of present LDH-Ise/dye LB films were investigated by UV-vis and Fourier transform infrared (FT-IR). The present research work provides new clues for the development of gas sensors and chemical switches as well as the preparation of effective functional self-assembled films.