Effects of Salt on the Gelation Mechanism of a d-Sorbitol-Based Hydrogelator

Abstract

The effect of salt on the gelatinization of 2,4-(3,4-dichlorobenzylidene)-D-sorbitol (DCBS), a novel low-molecular-weight gelator, was studied. DCBS showed pronounced hydrogelation and the electron micrographs indicated that the hydrogels consists of globular aggregates. Addition of NaCl to the aqueous medium accelerated the gelation process and also caused the gel's morphology to change from globular to long fibers. In addition, the thermal properties of the hydrogels were improved with the addition of NaCl. UV-vis and fluorescence emission spectra showed that extensive aggregation of the phenyl rings was responsible for the gelation. The presence of NaCl induced a red shift in the emission peaks of DCBS and a decrease of the pyrene polarity index I1/I3 in the gels, which indicated that there was more π-π stacking in the hydrogels with NaCl than in the gels without NaCl. Variable-temperature (1)H NMR spectra further demonstrated that the π-π interactions were enhanced by NaCl. FTIR studies showed that hydrogen bonding was also a contributing factor in the gelation process. Wide-angle X-ray diffraction (WXRD) showed that the hydrogels had a layered structure which did not change with the addition of NaCl. Density functional theory (DFT) calculations indicated the possible molecular packing of the gelator in the nanofibers.

Organic Gelators as Growth Control Agents for Stable and Reproducible Hybrid Perovskite‐Based Solar Cells

“…This ensures that the solvent mixture can be gelled. [25] We first tested the gelling ability of either DBS derivative by adding 0.1 wt%, 0.5 wt% or 1 wt% of these LMOGs to γBL-DMSO, followed by heating these mixtures to 125 °C while stirring until clear solutions were obtained. Cooling these solutions to room temperature, we find that MDBS forms a relatively weak gel, while DMDBS forms a mechanically more stable gel (Figure.…”

“…We attribute this behavior to the fact that the gelation behavior of LMOGs in a complex environment of solvated salts often is different when compared to a scenario where they are used in a solvent system without salts. [25] This could be a beneficial finding when formulating 'inks' that are compatible with solution-based coating and manufacturing methodologies as undesirable, early-stage gelation can be prevented. [23] To quantify the above observations and to obtain further information on the potential network formation of the LMOGs and how this changes the interplay between the solvent molecules and the MAPbI3 precursors, [26,27] we measured the variation of the complex viscosity (η*) of MAPbI3, MAPbI3-MDBS and MAPbI3-DMDBS solutions with frequency (Figure 2a), as well as their frequency-dependent storage (G′) and loss (G′′) moduli (Figure 2b-d).…”

Collective force generated by multiple biofilaments can exceed the sum of forces due to individual ones

“…Thus study of more complex models with explicit ATP/GTP hydrolysis are warranted to get convinced that the interesting collective phenomenon is expected in real biofilament experiments in vitro. In the literature, there are three different models of ATP/GTP hydrolysis, namely the sequential hydrolysis model [11,14] and the random hydrolysis model [6,15,25], and a mixed cooperative hydrolysis model [13,26,27]. In this section, we investigate the collective dynamics within the random model as it is a widely used model and is thought to be closer to reality [7].…”

Investigations on Carboxy Dibenzylidene Sorbitol Hydrogels Using EPR Spectroscopy

“…The gel properties are studied by a variety of physicochemical methods: rheological measurements [3,6] (mechanical properties), electronic microscopy such as SEM, TEM (morphology) [3,7,8], UV-Vis, NMR and UV circular dichroism, and differential scanning calorimetry [3].…”