Pyrene‐based fluorescent supramolecular hydrogel: scaffold for nanoparticle synthesis

Abstract

AbstractThe present work illustrates the design and development of pyrene‐based fluorescent supramolecular hydrogel consisting of l‐phenylalanine residue as the linker and ethyleneoxy unit with free primary amine at C‐terminal. The gelator efficiently immobilized aqueous media, and the critical gelation concentration (CGC) was found at 2.8 mM of the compound. Interestingly, the presence of pyrene moiety in the structure made the hydrogel intrinsically fluorescent. The self‐aggregation properties of the thermo‐reversible hydrogel were investigated using different microscopic and spectroscopic techniques such as high‐resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR) spectroscopy, fluorescence spectroscopy, and X‐ray diffraction (XRD) spectroscopy. A balanced participation of noncovalent interactions like hydrogen bonding, π‐π stacking, and van der Waals interaction was identified as the driving force for gelation. Rheological experiments were performed to confirm the viscoelastic nature of the prepared hydrogel. Furthermore, primary amine (─NH2) group of hydrogelator was utilized for the in situ synthesis of silver nanoparticles (AgNPs) within the soft material under sunlight in the absence of any external reducing and stabilizing agent.