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.