Development and Properties of Gelators and Thickeners

作者：Hanabusa Kenji^*

来源：Kobunshi Ronbunshu, 2015, 72(8): 491-504.

DOI：10.1295/koron.2015-0018

• Gelator
• Thickener
• Gel
• Physical Gel
• Hydrogen Bond
• Thixotropy
• Gelation-Driving Segment

Low molecular weight compounds, which can gel and thicken solvents; are introduced. The former compounds are called "gelators" and the later ones are called "thickeners". The relationship between physical gelation of solutions and crystallization is explained. Crystallization is a phenomenon by which crystals separate from a solution by a complete three-dimensional arrangement of the solute molecules through intermolecular interactions. On the other hand, physical gelation is caused by trapping solvent in fibrous networks which are formed by gelator molecules through intermolecular interactions. Driving forces for both gelation and crystallization are cooperating noncovalent interactions, such as hydrogen bonding, van der Waals interaction, electrostatic interaction, and pi-pi interaction. Amino acids derivatives as typical gelators are described and the new concept of "gelation-driving segments" is proposed. On the basis of gelation-driving segments, many functional gelators and polymer-type gelators can be prepared easily. Cyclo(L-aparaginyl-L-phenylalanyl) derived from an artificial sweetener is also an excellent gelator. The cyclo(dipeptide) can gel a wide variety of ionic liquids. The gelator makes ionic liquids potentially very useful for gel electrolytes. 1,3,5-Benzenetricarboxamide, cis-1,3,5-cyclohexanetricarboxamide, and aminoisophthalic acid derivatives act as thickeners for hydrocarbons and mineral oils. Finally, low molecular weight compounds showing thixotropic behavior are mentioned.

• 出版日期2015