Stimuli-responsive noniridescent structural color of thin-film coating based on multilayered nanosheets preserving interlayer space

Abstract

Two-dimensional (2D) anisotropic structures have advantages for designing functional materials. Layered materials accommodate guests in the interlayer space. Exfoliated nanosheets are used as units to obtain the organized architectures. If exfoliated nanosheets preserving multilayered structures are prepared, both the intercalation and building-block capabilities can be used for functionalization. In the present work, stimuli-responsive thin-film coating with noniridescent structural color was prepared using the exfoliated nanosheets with the multilayered structures. The precursor layered composite of a host transition-metal oxide and guest organic molecule was exfoliated into the surface-modified nanosheets. The resultant nanosheet was not monolayer but multilayers with the interlayer space. Coating the exfoliated nanosheets provided the thin film with uneven thickness exhibiting noniridescent structural color. As the additional guest molecules were introduced into the interlayer space of the multilayers in the nanosheet, an increase in the film thickness induced the changes in the structural color. Harmful biogenic amines and their mixtures were colorimetrically quantified using the thin-film sensor. The thin-film coating of the multilayered nanosheets has potentials for a variety of sensing applications.