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Low Molecular-Mass Organic Gelators (LMOGs) are a relatively new and dynamic soft materials capable of numerous possible applications; LMOGs are the monomeric sub-unit which form self-assembled fibrillar networks (SAFINs) that entrap solvent between the strands.〔Frkanec, L.; Zinic, M. Chiral bis(amino acid)- and bis(amino alcohol)-oxalamide Gelators. Gelation Properties, Self-Assembly Motifs and Chirality Effects” 2010 ''Chem. Commun.'' 46, 522-537.〕 SAFINs arise from the formation of strong non-covalent interactions between LMOG monomeric sub-units. As SAFINs are forming, the long fibers become intertwined and trap solvent molecules. Once solvent molecules are entrapped within the network, they are immobilized by surface tension effects. The stability of a gel is dependent on the equilibrium between the assembled network and the dissolved gelators. One characteristic of an LMOG, that demonstrates its stability, is its ability to contain an organic solvent at the boiling point of that solvent due to extensive solvent-fibrillar interactions.〔Hafkamp, R. J. H.; Feiters, M. C.; Nolte, R. J. 1999 ''J. Org. Chem.'' 64, 412.〕 Gels self-assemble through non-covalent interactions such as π-stacking, hydrogen-bonding, or Van der Waals interactions to form volume-filling 3D networks. Self-assembly is key to gel formation and dependent upon reversible bond formation. The propensity of a low molecular weight molecule to form LMOGs is classified by its Minimum Gelation Concentration (MGC). The MGC is the lowest possible gelator concentration needed to form a stable gel. A lower MGC is desired to minimize the amount of gelator material needed to form gels. Super gelators have a MGC of less than 1 wt%. ==Background and Significance== LMOGs were first reported in the 1930s, but advances in the field were more often than not discoveries of chance; as there existed little theoretical understanding of gel formation. During this time LMOGs found applications in thickening lubricants, printing inks, and napalm.〔Esch, J. H. We Can Design Molecular Gelators, But Do We Understand Them? 2009 ''Langmuir'' 25(''15''), 8392-8394.〕 Interest in the field dwindled for several decades until the mid-1990s when Hanabusa, Shinkai, and Hamilton designed numerous LMOGs which form thermoreversible intermolecular amide-carbonyl hydrogen bonds.〔Hanabusa, K.; Tange, J.; Taguchi, Y.; Koyama, T.; Shirai, H.Small Molecular Gelling Agents to Harden Organic Liquids: Alkylamide of N-Benzyloxycarbonyl-L-valyl-L-valine 1993 ''J. Chem. Soc. Commun.'', 390.〕 The LMOGs developed by Hanabusa ''et. al'' were suitable for forming hard gels, including gels with chloroform, which had been resistant to gelation prior to their discovery. These new LMOGs were rationally designed and represented the first time that scientists had been able to discover new LMOGs based on supramolecular principles. From these earliest studies and screening numerous compounds, it was determined that for thermoreversible gels based on the amide-carbonyl hydrogen bond, amino acid structure, enantiopurity, hydrophilic-lypophilic ratio, and increasing peptide substitution greatly affected the gelling ability of various new compounds. The aforementioned principles that developed in this field's infancy have proved successful in allowing researchers to tune LMOGs for different functions. Today, LMOGs have been extensively studied for their unique properties. This newfound functional diversity has led to a wide range of possible applications for LMOGs in agriculture, drug delivery, pollutant/heavy metal remediation, luminescent devices, and chemical sensing. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Low Molecular-Mass Organic Gelators」の詳細全文を読む スポンサード リンク
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