Organogel formation rationalized by Hansen solubility parameters: influence of gelator structure

Abstract

Some organic compounds form gels in liquids by forming a network of anisotropic fibres. Based on extensive solubility tests of four gelators of similar structures, and on Hansen solubility parameter formalism, we have probed the quantitative effect of a structural variation of the gelator structure on its gel formation ability. Increasing the length of an alkyl group of the gelator obviously reduces its polarity, which leads to a gradual shift of its solubility sphere towards lower δp and δh values. At the same time, its gelation sphere is shifted - to a much stronger extent - towards larger δp and δh values.

Steric‐Structure‐Dependent Gel Formation, Hierarchical Structures, Rheological Behavior, and Surface Wettability

“…However, not all self‐assemblies of LMW molecules result in gelation. Diverse molecular building blocks derived from long‐chain hydrocarbons or steroid derivatives, amino acid derivatives, urea, carbohydrate‐derived systems, metal complexes, charge‐transfer complexes, macrocycles, and organic salts have been used to synthesize LMW gels . Cholesterol derivatives are very important gelators in supramolecular chemistry .…”

“…Diverse molecular building blocks derived from long-chain hydrocarbons or steroid derivatives, amino acid derivatives, urea, carbohydrate-derived systems, metal complexes, charge-transfer complexes, macrocycles, and organic salts have been used to synthesize LMW gels. [30][31][32][33][34] Cholesterol derivativesa re very importantg elators in supramolecular chemistry. [35] Weiss and co-workersr eportedt he first rational synthesis of cholesterol-based LMW organic gels.…”

Self‐Assembled Nanofibrilar Networks: Boosting Hydrogelation Efficiency by Replacement of a Pyridine Moiety by a Quinoline One

“…Insight into the molecular details of self‐assembled fiber formation have been reported recently . In the case of gels in organic solvents, solubility has been used to understand gelation efficiency . Much less studies have been carried out in this direction regarding gel formation in water although hydrophobic character and computational methods have been used to rationalize/predict gelation.…”

“…[5] In the case of gels in organic solvents, solubility has been used to understand gelation efficiency. [6][7][8][9] Much less studies have been carried out in this direction regarding gel formation in water although hydrophobic character [10] and computational methods [11][12] have been used to rationalize/predict gelation. Given a molecule capable of forming gels, choosing the structural variations required to improve its gelation efficiency, namely, the minimum gelator concentration required to form a hydrogel (mgc), is particularly challenging.…”

Improved Efficiency of Molecular‐Gel Formation by Adjusting Preorganization of Amino‐Acid‐Derived Flexible Molecules: A NMR and Thermodynamic study

“…Their intrinsic reversibility and responsiveness to stimuli, together with their biodegradable nature, provide distinct advantages compared with many polymeric analogs . The gelation efficiency of small molecules is difficult to rationalize, and interesting studies in this area focused on factors such as solubility, chirality, and the presence of the appropriate units to achieve intermolecular bonding have been described . In summary, molecules capable of self‐assembly should present a preferential direction of self‐assembly, giving rise to 1D, fibril‐like, aggregates with sufficient free energy of aggregation in the required solvent.…”