Supramolecular nanofiber formation from commercially available arginine and a bola-type diacetylenic diacid via hydrogelation

A diacetylenic-acid arginine salt gelated water. The supramolecular structure and optical properties of the resultant hydrogel were examined by optical microscopy, electron microscopy, X-ray diffraction and ultraviolet (UV)-absorption and circular dichroism (CD) spectroscopies. Microscopic images showed that 10, 12-docosadiynedioic acid arginine salt formed a fibrous structure. X-ray diffraction and nuclear magnetic resonance measurements indicated guanidinium-carboxylate interaction. Upon UV irradiation, the gel polymerized to diacetylene oligomers, with a concomitant color change from white to orange. After the removal of arginine, CD spectra indicated that the diacetylene oligomers maintained chirality. Polymer Journal (2012) 44, 646-650; doi:10.1038/pj.2012.46; published online 4 April 2012