Efficient transition metal dichalcogenides exfoliation by cellulose nanocrystals for ultrabroad-pH/temp stable aqueous dispersions and multi-responsive photonic films

A major challenge in developing 2D transition-metal dichalcogenides nanosheets (TMD ns) as nanofillers, catalysts and photothermal reagents lies in its colloidal stability and scalable production. Herein, a biomimetic hybrid strategy to efficiently exfoliate and stably disperse TMD ns in a low-cost, environment-friendly manner is demonstrated. Cellulose nanocrystal (CNC) with controllable morphology and surface chemistry is acted as ideal assisted exfoliation reagent and stabilizer for highly concentrated and thin-layer TMD ns aqueous dispersions. Ultrabroad-pH/temperature (pH = 1–13, temperature = 1–95 °C) stable aqueous dispersions of TMD ns/CNC hybrids and the self-assembly of CNC allow the successful construction of flexible, rapid, and multi-stimuli responsive photonic films, e.g., mechanical strain, humidity and photothermal, providing an avenue for artificial skin, flexible sensor, and smart screen & window applications.