Versatile supramolecular pH-tolerant hydrogels which demonstrate pH-dependent selective adsorption of dyes from aqueous solution.

We report a novel gelator functionalised with hydrazides (as replacements for carboxylic acids) which, as a result, is able to assemble into hydrogels across a wide pH range - this gelator exhibits pH-switchable dye adsorption-desorption dependent on protonation of the target dyes and their resulting interactions with the self-assembled gel nanofibres.