Controlled Self-Assembly Of Responsive Polymer With Well-Defined Topological Structure Based On New Stimulus

Stimuli-responsive macromolecules are defined as such a class of polymersthat receive external stimulus, leading to the transformation of their structuresirreversibly or reversibly. These stimuli can affect the behaviors and propertiesin bulk or solution, and as a result, responding a chemical or physical output. Inthis thesis, we are mainly focused on the exploration of the new syntheticapproach of stimuli-responsive polymers based on extensively exploitation ofnew stimulation, for the purpose of integration of stimulus-topology-function.The work includes three parts of results as follows:1) In the aspect of stimulation mode: We have developed a series of novel stimulussources for specific functional groups and polymer systems: voltage-sensitive mode isused for bio-mimicking the cell membrane potential controlled membrane switch-on;CO₂-responsive mode uses to gradually protonate amidine group in polymer side chain,driving the polymeric vesicles to “breathe”; visible light-responsiveness uses to promotethe addition-fragmentation reaction of dialkoxyanthracene species in polymer mainchain, which leads to the disruption of polymeric micelles. Through exploiting thesenew stimulations, the operability and biocompatibility in human cells are strengthened.It is anticipated that these novel approaches could be applied in drug delivery andnanocapsules.2) In the aspect of topological engineering: Based on the chemical structureand self-assembly behavior of traditional block copolymers, we have developeda homopolymer orthogonal self-assembly approach （HOSA）. HOSA method canlinearly connect two or more homopolymers into the pseudocopolymer on thebasis of specific supramolecular moieties at the end of polymer chain, differingfrom covalent block copolymers. These active connections possessing stimulisensitivity can realize the assembly and disassembly of the supramolecularcopolymer. This novel strategy simplifies complex organic synthesis, and hashigher responsiveness and better reversibility, and can form multiple topologicalsupramolecular copolymers through mixing.3) In the aspect of functions: We developed these smart polymer to act asnanocontainers for controlled vehicles and release, as nanosensors for chemical sensors, and as models for bio-mimicking the evolution or involution of cell ororganelle.