Tunable Chiral Luminescent Nanogels with Multiresponses by Supramolecular Chirality Transfer and Their Applications as Artificial Smart Eyes.

Abstract

Colorful chiral emitting nanomaterials exhibit great potential in soft displays, bionic skin, perception organs of soft robots, smart sensors, and human-machine dialogue materials. Inspired by the involvement of chiral molecules in the bioluminescence process of natural organisms, flexible and tunable chiral fluorescent nanogels with multiple stimulus luminescence responses were constructed by supramolecular chirality transfer. The fluorescent naphthalimide-containing ionic liquid (NAIL) guest molecules and polyethylene glycol were assembled on CNC via host-guest supramolecular interactions and formed the photonic crystal nanogels. Chiral transfer from the helical layered nanostructure of the CNC photonic crystal template to the molecular level was achieved, which induced right-handed chiral emission in the photonic crystal nanogel. The chiral nanogels demonstrated flexibility, tunable intensities of the right-handed chiral luminescence, adjustable iridescent colors, and sensitive multistimulus response. The nanogels showed sensitive responsiveness in circularly polarized luminescence toward various stimuli like organic solvent molecules, H₂O molecules, and acid/alkali chemicals, which can serve as artificial smart eyes for environmental perception and molecular recognition. The nanogels with tunable circularly polarized fluorescence exhibit great potential in information recording and perception organs of soft robots and advanced molecular sensors.