Hybrid gels by combining low molecular weight glycolipid gelators with agarose: a promising soft material for efficient dye removal

Abstract

Hybrid gels formed by combining low molecular weight gelators (LMWGs, glycolipids) and polymeric gelators (agarose) are reported. These hybrid soft materials showcase the successful merging of LMWGs’ unique properties with agarose polymer networks, resulting in a novel material with overall enhanced characteristics. Amphiphilic glycolipid-based LMWGs containing glucose (PHY-G) and lactose (PHY-L) moieties as hydrophilic parts have been formulated. Their gelation behavior in a broad spectrum of solvents was investigated, revealing their ability to form stable supramolecular gels in a mixed solvent system of DMSO–water. Minimum gelation concentration (MGC) values for the supramolecular gels of PHY-G and PHY-L were found to be 9 mg mL⁻¹ and 15 mg mL⁻¹, respectively. These formulated supramolecular/hybrid gels were further evaluated to check their physicochemical properties. The thermal stability of hybrid gels was higher than their respective supramolecular gels. Rheological analysis revealed that the hybrid gels have much higher mechanical strength and stability compared to their component gels, with nearly 10-fold increase in modulus values. The microstructure of the hybrid gels was observed to be a self-assembled fibrillar supramolecular gel network interwoven with the agarose network. The interaction between the glycolipids and agarose gel network in the hybrid gels was substantiated by FTIR and XRD analyses. Moreover, Congo red was chosen as a model dye to study their adsorption behavior. Dye removal from its aqueous dye solution using hybrid gels with respect to time was studied using UV-vis spectroscopy. A hybrid gel with the PHY-G glycolipid achieved 98% removal of Congo red within 36 hours. Overall, the study demonstrated a good strategy for the fabrication of glycolipid–polysaccharide hybrid gels as a sustained medium for dye removal. It will also open a new direction for designing self-assembled glycolipid–polysaccharide hybrid gels.