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Supramolecular hydrogels were prepared in the mixturesof a chiralamphiphilic lithocholic acid (LCA) and a nonionic surfactant, dodecyldimethylamineoxide (C12DMAO), in water. With the addition of LCA toC12DMAO micellar solutions, a transition from micellesto gels occurs at room temperature. Hydrogels can form at very lowconcentrations (below 0.1 wt %), exhibiting a super gelation capability.The rheological measurements show a strong mechanical strength withan elastic modulus exceeding 5000 Pa and a yield stress exceeding100 Pa. Microstructures determined by TEM, SEM, and AFM observationsdemonstrate that the gels are formed by intertwined helical fibrils.The formation of fibrils is induced by enormous cycles of units composedof two LCA molecules and four C12DMAO molecules drivenby comprehensive noncovalent interaction, especially the hydrogenbonds produced in two reversed LCA molecules and the C12DMAOH+–C12DMAO pairs. The xerogels showexcellent adsorption capability of the toxic dye with a maximum adsorptionvalue of 202 mg·g–1. [ABSTRACT FROM AUTHOR]

Gelation behavior of lithocholate (LC(-)) mixed with different monovalent cations in water was detected. The hydrogels consisting of tubular networks were formed by introducing alkali metal ions and NH4(+) to lithocholate aqueous solutions at room temperature. The formation of tubular structures was considered to be mainly driven by the electrostatic interaction with the assistance of a delicate balance of multiple noncovalent interactions. It is interesting that the increase in temperature can induce a significant enhancement in strength of the hydrogels, accompanied by the formation of bundles of tubules and larger size aggregates. The mechanism of the temperature-induced transition can be explained by the "salting-out" effect and the electric double layer model. The hydrogels showed very high adsorption efficiency and adsorption capability for the cationic dyes and were promising to act as toxic substance adsorbents.