title: Superhydrogels of nanotubes capable of capturing heavy-metal ions.
abstract: Self-assembly regulated by hydrogen bonds was successfully achieved in the system of lithocholic acid (LCA) mixed with three organic amines, ethanolamine (EA), diethanolamine (DEA), and triethanolamine (TEA), in aqueous solutions. The mixtures of DEA/LCA exhibit supergelation capability and the hydrogels consist of plenty of network nanotubes with uniform diameters of about 60 nm determined by cryogenic TEM. Interestingly, the sample with the same concentration in a system of EA and LCA is a birefringent solution, in which spherical vesicles and can be transformed into nanotubes as the amount of LCA increases. The formation of hydrogels could be driven by the delicate balance of diverse noncovalent interactions, including electrostatic interactions, hydrophobic interactions, steric effects, van der Waals forces, and mainly hydrogen bonds. The mechanism of self-assembly from spherical bilayer vesicles into nanotubes was proposed. The dried hydrogels with nanotubes were explored to exhibit the excellent capability for capturing heavy-metal ions, for example, Cu(2+), Co(2+), Ni(2+), Pb(2+), and Hg(2+). The superhydrogels of nanotubes from the self-assembly of low-molecular-weight gelators mainly regulated by hydrogen bonds used for the removal of heavy-metal ions is simple, green, and high efficiency, and provide a strategic approach to removing heavy-metal ions from industrial sewage.
authors.affiliation: Key Laboratory for Colloid and Interface Chemistry & Key Laboratory of Special Aggregated Materials, Shandong University, Ministry of Education, Jinan 250100 (P.R. China), Fax: (+86) 531-856-4464.
authors.forename: Shasha
authors.initials: S
authors.lastname: Song
authors.forename: Haiqiao
authors.initials: H
authors.lastname: Wang
authors.forename: Aixin
authors.initials: A
authors.lastname: Song
authors.forename: Jingcheng
authors.initials: J
authors.lastname: Hao
mesh_terms: D000588:Amines / Q000737:chemistry; D019856:Ethanolamine / Q000737:chemistry; D004983:Ethanolamines / Q000737:chemistry; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008095:Lithocholic Acid / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry*; D008968:Molecular Conformation; D043942:Nanotubes / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D000588:Amines; D004983:Ethanolamines; D020100:Hydrogels; D007477:Ions; D019216:Metals, Heavy; D019856:Ethanolamine; D008095:Lithocholic Acid; C009546:triethanolamine; C020283:diethanolamine
keywords: gels; heavy-metal ions; nanotubes; self-assembly; surfactants