The quest for the simplest possible organogelators and some properties of their organogels

Abstract

Nesse trabalho é apresentada uma revisão sobre esforços recentes na busca pela classe mais simples de moléculas orgânicas capazes de gelificar grandes volumes de líquidos, com ênfase na abordagem adotada pelos autores. Apresentam-se, também, propriedades de alguns destes compostos bem como de seus organogéis. Alguns dos desafios futuros para o desenvolvimento desta área são discutidos.The search for the simplest structural class of organic molecules capable of gelling large amounts of organic liquids is reviewed with an emphasis on the approach taken by the authors. The properties of several of the gelators, as well as their gels with various organic liquids, are presented. Some challenges to future developments in the field are mentioned.

Amorphous and crystalline aerosol particles interacting with water vapor: conceptual framework and experimental evidence for restructuring, phase transitions and kinetic limitations

“…On the other hand, some organic substances ("gelators", including carbohydrates and proteins) are able to form gel-like structures (supramolecular networks) that may inhibit molecular diffusion in the particle bulk and reinforce kinetic limitations of deliquescence (Farhat et al, 1997;Abdallah and Weiss, 2000;Estroff and Hamilton, 2004;He et al, 2007). Moreover, the filling or formation of aqueous pockets in gel-like structures can lead to stepwise swelling in the course of hydration and gradual deliquescence of amorphous aerosol particles (see results reported below and by Mikhailov et al, 2004).…”

Rheological characterisation of bis-urea based viscoelastic solutions in an apolar solvent

“…In the literature, a great variety of chemical structures has been reported for organogelators [1,2] but when focusing on molecules that self-assemble into fibrillar aggregates, the gelation may be understood by the entanglement and/or the branching of these fibrilles leading to the formation of a network. The initial selfassembly of the organogelators may be driven by the possibility for the molecules to form intermolecular H-bonds [3][4][5][6][7][8][9] or to develop other specific interactions such as dipole or van der Waals forces [10][11][12]. When each small molecule is linked to its neighbours by noncovalent reversible bonds, the resulting chains may be viewed as "reversible polymers" and can undergo scission and recombination mechanisms which affect the overall dynamics of the system.…”

Swelling behavior and characterization of alcohol-specific superabsorbing gels based on acrylic acid and allyl tetrasodium thiacalix[4]arene tetrasulfonate

“…Organogels are materials, which can solidify organic solvents; they may be composed of low molecular weight or polymeric materials [1]. Organogels can be applied in different areas, such as in the controlled release of drugs and fragrances [2][3][4], and the surfactant industry [5]. Also, they have been used as fuel gels, particularly in outdoor applications for warming, cooking, boiling water, fire starters, or hand sanitizers [2,6].…”