Thermal and ultrasound induced gelation of bis(acyl-semicarbazides)—Investigations on the anion tuning and dye adsorbing properties of their gels

Abstract

Herein we report the anion tuning and dye adsorbing properties of aromatic bis(acyl-semicarbazides) carrying aromatic core and substituents of varying alkyl chain length. Gelator with a specific spacer length (C10) was chosen to study the effect of stimuli such as temperature, ultrasound and anions on gel strength, mode of interaction and morphology. A three dimensional network structure composed of fibers of varying diameters were observed for gels obtained by thermal treatment whereas a lamellar aggregation resulted upon ultrasound treatment as noticed in SEM studies. Ultrasound induced gels (USIG) exhibited higher gel-sol transition temperature and strength than temperature induced gel as observed from dynamic oscillatory studies, FT-IR and XRD due to the differences in the modes of aggregation. The gels could be tuned in the presence of anions at different concentrations and addition of 5 equivalents of F− and AcO− induced gel-sol transition. In addition, these organogels adsorbed dyes such as crystal violet and rhodamine-B from water every effectively which was confirmed by visual method and quantified by UV–vis spectrophotometry.