Construction Of Water-soluble Supramolecular Polymers Based On Pillar[5]Arenes

Loosely defined,supramolecualr polymers refer to polymers in which the discrete monomers are held together by noncovalent interactions.Owing to the introduction of the dynamic concovalent interactions,supramolecular polymers exhibit peculiar properties including reversibility,self-healing,stimuli-responsiveness,which endows them as promising candidates for construction of accommodative and exquisite materials.The construction of stimuli-responsive supramolecular polymers in water broadened the application for supramolecular polymers,especially in biologic systems as most biologic process occur in aqueous solution and the fabrication of pH-responsive supramolecular systems is of great importance because of the numerous pH gradients that exist in both normal and pathophysiological states which can bring controlled drug release and gene delivery feasibility.The thesis mainly includes two parts as follows:In the first part,we synthesized a complementary A-B type monomer 1 bearing eight diethylammonium groups and a long alkyl chain as the guest moiety.Driven by hydrophobic interactions and C-H…? interactions between alkyl chain and the cavity of pillararene,a linear supramolecular polymer was efficiently constructed in water.In order to confirm the formation of the supramolecular polymer,various characterization techniques including concentration-dependent 1H NMR,NOESY,DOSY,specific viscometry and SEM were carried out.More interestingly,we demonstrated that the assembly and disassembly of this supramolecular polymer can be reversibly controlled by changing the solution's pH.The good water-solubility and pH-responsiveness of the supramolecular polymer provided a great potential in many bio-relevant fields,such as drug delivery systems,controlled release and smart bioactive surface.In the second part,we designed and synthesized the phosphonate-functionalized copillar[5]arene.The introduction of eight phosphonate groups on pillararene can not only enhance its biocompatibility but also endow it with stimulative responsibility which would broaden the structural toolbox for fabricating pillararene-based biocompatible self-assembly systems.Dri-ven by hydrophobic interactions and C-H…?interactions between decyl moiety and the cavity of pillararene,a linear supramolecular polymer was further fabricated from this AB type monomer in water,and various characterization techniques including concentration-dependent 1H NMR,NOESY,DOSY,specific viscometry were carried out to study the supramolecular polymerization process.Additionally,we demonstrated that the assembly and disassembly of this supramolecular polymer can be reversibly controlled by adjusting the solution's pH,which provided potential applications especially in bio-relevant fields,such as drug delivery systems and controlled release.