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pH‐Tunable Hydrogelators for Water Purification: Structural Optimisation and Evaluation
Author(s) -
Wood Daniel M.,
Greenland Barnaby W.,
Acton Aaron L.,
RodríguezLlansola Francisco,
Murray Claire A.,
Cardin Christine J.,
Miravet Juan F.,
Escuder Beatriu,
Hamley Ian W.,
Hayes Wayne
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201102137
Subject(s) - aqueous solution , chemistry , thiourea , methylene blue , cationic polymerization , hydrolysis , urea , methyl orange , adsorption , transmission electron microscopy , chemical engineering , absorption of water , orange g , nuclear chemistry , organic chemistry , materials science , catalysis , engineering , composite material , photocatalysis
A focused library of potential hydrogelators each containing two substituted aromatic residues separated by a urea or thiourea linkage have been synthesised and characterized. Six of these novel compounds are highly efficient hydrogelators, forming gels in aqueous solution at low concentrations (0.03–0.60 wt %). Gels were formed through a pH switching methodology, by acidification of a basic solution (pH 14 to ≈4) either by addition of HCl or via the slow hydrolysis of glucono‐δ‐lactone. Frequently, gelation was accompanied by a dramatic switch in the absorption spectra of the gelators, resulting in a significant change in colour, typically from a vibrant orange to pale yellow. Each of the gels was capable of sequestering significant quantities of the aromatic cationic dye, methylene blue, from aqueous solution (up to 1.02 g of dye per gram of dry gelator). Cryo‐transmission electron microscopy of two of the gels revealed an extensive network of high aspect ratio fibers. The structure of the fibers altered dramatically upon addition of 20 wt % of the dye, resulting in aggregation and significant shortening of the fibrils. This study demonstrates the feasibility for these novel gels finding application as inexpensive and effective water purification platforms.