Amphiphilic sulfamide as a low-molecular-mass hydrogelator: A novel mode of 3-D networks formed by hydrogen-bond-directed 2-D sheet assemblies.
Asymmetrically substituted amphiphilic sulfamide, N-tetradecyl-N'-(6-dimethylaminohexyl)-sulfamide (3c) having a dimethylamino group at one end of the side chain, showed a strong ability to form two-dimensional (2-D) sheet-like assemblies by the 2-D hydrogen-bond networks between sulfamide moieties. Upon protonation of the amino group with acid, the cationic ammonium form of 3c induced effective hydrogelation (minimum gelation concentration: 0.5wt%) to yield a translucent, self-standing hydrogel. Infrared (IR) spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies confirmed formation of the fibrous assemblies of the hydrogen-bond-directed 2-D nanosheets in the hydrogel. A novel mode of three-dimensional (3-D) networks was formed by branching and recombination of hydrogen-bond networks and knit-like linkages between the assemblies. The storage and loss moduli of the hydrogel (2wt%) were measured to be in the range of 10(2) and 10(3)Pa, showing relatively high mechanical stability.
Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
Shin-ichiro
S
Kabashima
Motohiro
M
Kageyama
Tomomichi
T
Okano
Isao
I
Yoshikawa
Koji
K
Araki
D000577:Amides / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D006860:Hydrogen Bonding; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008970:Molecular Weight; D012212:Rheology; D013055:Spectrophotometry, Infrared; D013455:Sulfur / Q000737:chemistry*; D014961:X-Ray Diffraction
D000577:Amides; D020100:Hydrogels; D013455:Sulfur
Hydrogel; Hydrogen bond; Sulfamide; Supramolecule