Institut Charles Sadron, 23 rue du Loess - BP 84047, 67034 Strasbourg, Cedex 2, France.
Laboratoire Charles Coulomb, UMR 5221, CNRS-Université de Montpellier , 34095 Montpellier, France.
Langmuir. 2016 May 17;32(19):4975-82. doi: 10.1021/acs.langmuir.6b00995. Epub 2016 May 5.
Binary c-T phase diagrams of organogelators in solvent are frequently simplified to two domains, gel and sol, even when the melting temperatures display two distinct regimes, an increase with T and a plateau. Herein, the c-T phase diagram of an organogelator in solvent is elucidated by rheology, DSC, optical microscopy, and transmitted light intensity measurements. We evidence a miscibility gap between the organogelator and the solvent above a threshold concentration, cL. In this domain the melting or the formation of the gel becomes a monotectic transformation, which explains why the corresponding temperatures are nonvariant above cL. As shown by further studies by variable temperature FTIR and NMR, different types of H-bonds drive both the liquid-liquid phase separation and the gelation.
有机凝胶剂在溶剂中的双元 c-T 相图通常简化为两个区域，凝胶和溶胶，即使熔融温度显示出两个明显的区域，即随 T 增加和平台增加。在此，通过流变学、DSC、光学显微镜和透射光强测量阐明了溶剂中有机凝胶剂的 c-T 相图。我们证明了在阈值浓度 cL 以上，有机凝胶剂和溶剂之间存在混溶性间隙。在这个区域，凝胶的熔化或形成变成了一个均一的转变，这解释了为什么在 cL 以上对应的温度是不变的。通过进一步的变温 FTIR 和 NMR 研究表明，不同类型的氢键驱动了液-液相分离和凝胶化。
