These authors contributed equally to this paper.
Two-Component Hydrogels Comprising Fatty Acids and Amines: Structure, Properties, and Application as a Template for the Synthesis of Metal Nanoparticles
Article first published online: 9 JUN 2008
Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chemistry - A European Journal
Volume 14, Issue 21, pages 6534–6545, July 18, 2008
How to Cite
Basit, H., Pal, A., Sen, S. and Bhattacharya, S. (2008), Two-Component Hydrogels Comprising Fatty Acids and Amines: Structure, Properties, and Application as a Template for the Synthesis of Metal Nanoparticles. Chem. Eur. J., 14: 6534–6545. doi: 10.1002/chem.200800374
- Issue published online: 10 JUL 2008
- Article first published online: 9 JUN 2008
- Manuscript Received: 2 MAR 2008
- fatty acids;
- supramolecular chemistry;
- X-ray diffraction
Stearic acid or eicosanoic acid mixed with di- or oligomeric amines in specific molar ratios form stable gels in water. The formation of such hydrogels depends on the hydrophobicity of the fatty acid, and also on the type of amine used. The gelation properties of these two-component systems were investigated using electron microscopy, FTIR spectroscopy, 1H NMR spectroscopy, differential scanning calorimetry (DSC), and both single-crystal and cast-film X-ray diffraction. Results of FTIR spectral analysis suggest salt formation during gelation. 1H NMR analysis of the gels indicates that the fatty acid chains are immobilized in the gel state and when the gel melts, these chains regain their mobility. Analysis of DSC data indicates that increase in the spacer length in the di-/oligomeric amine lowers the gel-melting temperature. Two of these gelator salts developed into crystals and structural details of such systems could be secured by single-crystal X-ray diffraction analysis. The structural information of the salts thus obtained was compared with the XRD data of the self-supporting films of those gels. Such analyses provided pertinent structural insight into the supramolecular interactions that prevail within these gelator assemblies. Analysis of the crystal structure confirmed that multilayered lamellar aggregates exist in the gel and it also showed that the three-dimensional ordering observed in the crystalline phase is retained in only one direction in the gel state. Finally, the hydrogel was used as a medium for the synthesis of silver nanoparticles. The nanoparticles were found to position themselves on the fibers and produced a long, ordered assembly of gel–nanoparticle composite.