Dipeptide-based low-molecular-weight efficient organogelators and their application in water purification

The development of new low-molecular-weight gelations for organic solvents is motivated by several potential applications of gels as advanced functional materials. In the present study, we developed simple di-peptide-based organogelators with a minimum gelation concentration (MGC) of 6-0.15%, w/v in aromatic solvents. The organogelators were synthesized using different L-amino acids with nonpolar aliphatic/aromatic residues and by varying alkly-chain length (C-12 to C16). The self-aggregation behavior of these thermoreversible organogels was investigated through several spectroscopic and microscopic techniques. A balanced participation of the hydrogen bonding and van der Waals interactions is crucial for efficient organogelation, which can be largely modulated by the structural modification at the hydrogen-bonding unit as well as by varying the alkyl-chain length in both sides of the hydrophilic residue. Interestingly, these organogelators could selectively gelate aromatic solvents from their mixtures with water. Furthermore the xerogels prepared from the organogels showed a striking property of adsorbing dyes such as crystal violet, rhodamine 6G from water. This dye-adsorption ability of gelators can be utilized in water purification by removing toxic dyes from wastewater.