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Synthesis of a Bis‐Urea Dimer and Its Effects on the Physical Properties of an Amphiphilic Tris‐Urea Supramolecular Hydrogel
Author(s) -
Sawada Hiroki,
Yamanaka Masamichi
Publication year - 2018
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201800217
Subject(s) - supramolecular chemistry , self healing hydrogels , covalent bond , dimer , supramolecular assembly , amphiphile , supramolecular polymers , urea , polymer chemistry , self assembly , non covalent interactions , chemistry , materials science , nanotechnology , molecule , polymer , copolymer , hydrogen bond , organic chemistry
The successful development of stiff supramolecular gels is an important goal toward their practical application. One approach to stiffen supramolecular gels is to introduce covalent cross‐links. The bis‐urea dimer 2 , having a structure similar to that of the low‐molecular‐weight gelator 1 , was synthesized. Supramolecular hydrogels were formed from mixtures of 1 and 2 in appropriate ratios, with 2 acting as a covalent cross‐linker to connect the fibrous aggregates formed by the self‐assembly of 1 . The introduction of these covalent cross‐links greatly influenced the dynamic viscoelasticity of the supramolecular hydrogels. In the supramolecular hydrogel of 1 mixed with 5 % 2 , the storage modulus was 1.35 times higher than that of the supramolecular hydrogel of 1 alone, and the crossover strain was extended from 5 % to over 20 %. The supramolecular hydrogel of 1 and 2 was free‐standing and supported 13 times its own weight.