Supramolecular Polymer And Functionality From Amphiphile Based On Histidine

Low molecular weight organogels(LMWGs)are an important type of soft matters,in which an organic liquid phase is immobilized by the formation of a three-dimensional network composed of self-assembled nanostructures such as nanofibers,nanotubes and so on.The LMWGs have received increasing attentions in recent years,due to their potential applications in various fields,such as nanotechnology,tissue engineering,molecular recognition and supramolecular catalysis.In the dissertation,we have designed bolaamphiphile based on histidine,and investigated the gelation properties,self-assembled nanostructures and functionalization.(1)Bolaamphiphilic organogelator based on histidine were designed and synshesized(L-Bola and D-Bola),respectively.The strong hydrogen bond could be formed by the imidazole group of organgelator and dicarboxylic acid,resulting in assembling into the stable hydrogel.Therefore,supramolecular gels,supramolecular polymer and the chirality of co-assemblies are dependent on the molar ratios,flexibility and cis-trans configuration of diacid molecules.Meanwhile,the chirality of supramolecular co-assemblies of L-Bola assembled with various dicarboxylic acids and the D-Bola co-assemblies are mirror symmetry.(2)The assemblies of bolaamphiphilic histidine(Bola)co-assembled with the rigid acetylene dicarboxylic acid(DA)in water.The secondary nanostructures of supramolecular co-assemblies changed form the tiny nanofiber to the long helical fiber,increasing with molar ratio of DA/Bola.The stable hydrogel,even through the molar ratio is 16:1,is still obtained.Which is rarely reported in literature,as the extra dicarboxylic acids formed oligomer.Meanwhile,organic nanoflower rarely reported in the literature also can be obtained in water.(3)A chiral low-molecular-weight organogelator based on histidine assembled with the momomer of various achiral diacetylene acids in water mixed with DMF into gel,respectively.Upon UV-irradiation,the white co-gel polymerized into red co-gel or bule co-gel.A racile method of preparing macromolecular polymer by supramolecular self-assembly is introduced in this dissertation.Meanwhile,the chirality of polymer can be tuned by changing the length of chain,the position of triple bond on diacetylene acid and exploring the properties of intelligent PDA.