L-苯丙氨酸衍生物与脂肪胺构筑双组分超分子凝胶

Two-Component Supramolecular Organogels Formed from L-Phenylalanine Derivatives and Aliphatic Amines

设计合成了系列单链L-苯丙氨酸衍生物,该系列衍生物单组分没有胶凝性能.选择脂肪胺作为配对物,与L-苯丙氨酸衍生物组成双组分体系后能够胶凝许多有机溶剂形成凝胶.流变学测试显示该凝胶体系弹性模量(G′)比粘性模量(G′′)约高一个数量级,有着很好的机械性能,并且呈现出典型的类固体的流变学行为.傅里叶变换红外(FT-IR)光谱、核磁共振(NMR)谱、小角X射线衍射(SAXS)和扫描电镜(SEM)结果表明,凝胶中胶凝剂分子形成纤维状或片层状的聚集体,羧基(―COOH)和氨基(―NH2)的酸碱作用、酰胺基团间(―CONH―)的氢键作用以及分子间范德华作用力是形成该凝胶的主要驱动力.凝胶中胶凝剂分子自组装形成具有周期性的层状有序结构,层状结构进一步组装形成纤维状聚集体,最终形成三维网状结构阻碍溶剂流动形成凝胶.

A series of monochain L-phenylalanine derivatives were synthesized. L-Phenylalanine derivatives have no gelation abilities, but two-component systems consisting of L-phenylalanine derivatives and aliphatic amines can gelate various organic liquids. The structures of the aggregates in the organogels were investigated using Fourier-transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance （NMR） spectroscopy, small- angle X-ray scattering （SAXS）, rheological methods, and scanning electron microscopy （SEM）. The rheological measurements showed that the steady-state value of the storage elastic modulus （ G＇ ） was about 10 times larger than that of the loss elastic modulus （ G＂ ）, indicating that the organogels have good mechanical properties and gel-like characteristics. The SEM, FT-IR, and 1H NMR results showed that two-component organogels can self-assemble into fibrous or lamellar aggregates in organic liquids through acid-base interactions, intermolecular hydrogen bending of amide groups, and van der Waals interactions of long alkyl chains. The FT-IR and NMR spectra showed that the hydrogen-bonding and acid-base interactions were the main driving forces for the formation of self-assembled gels. The SAXS results indicated that the gelator molecules assembled into ordered lamellar structures in organic liquids. The ordered lamellar aggregates are juxtaposed and interlocked by van der Waals interactions to form a fibrous superstructure and are finally immobilized in the organic liquid.