Stable and sensitive stimuli-responsive anisotropic hydrogels for sensing ionic strength and pressure

Anisotropic hydrogels with a large mono-domain, nematic organization of cellulose nanocrystals (CNCs) were prepared. External stimuli such as ionic strength and pressure allow the hydrogels to change their shapes anisotropically through swelling/shrinking and expansion/contraction, respectively. These stimuli cause changes in a phase difference for the light passing through them while retaining the monodomain structure, leading to large color changes when the hydrogels are viewed between crossed polarizers.