Study On Assembling Behavior And Synthesis Of Hyperbranched Poly (Thiol–ether Amine)(hPtEa) Through Sequential "Thiol–ene" And "Epoxy–amine" Click Reactions

Recently,hyperbranched polymers have obtained increasing attention because of their highly branched three-dimensional globular structure as well as unique physical and chemical properties,and as a result,they have wide potential applications in drug delivery,nano-sensors,polymer coatings,polymer additive,and so on.So far,our group has developed a series of novel amphiphilic multi-responsive hyperbranched poly?ether amine?s?hPEA?,which are all responsive to environmental stimuli such as temperature,pH,and ionic strength.Meanwhile,there are a large amount of hydroxyl and amino groups in the backbone and periphery of hPEA,which can be further functionalized.However,this one-pot reaction via the A₂+B₃ approach should be carried out using a low concentration of monomers to avoid generating a cross-linked gel,so it is still a big challenge to control the reaction.In this dissertation,we demonstrated a novel strategy for the one-pot approach to synthesize hyperbranched poly?thiol–ether amine??hPtEA?through sequential“thiol–ene”and“epoxy–amine”click reactions.The two click reactions above both can be traced by using in situ ¹H-NMR spectra.The obtained hPtEA,with a high degree of branching?DB?of 0.83 and a molecular weight?Mn?of 8.6×10³,was composed of a large amount of hydroxyl groups in the backbone and amino groups in the periphery.Moreover,hPtEA could be further functionalized orthogonally due to the difference in the chemistry between the hydroxyl and amino groups.So fluorescent anthracene?AN?and carboxyl?SA?groups were introduced to the periphery and backbone of hPtEA,respectively,and the amphiphilic and zwitterionic hPtEA?SA-hPt EA-AN?was obtained.The resulting SA-hPt EA-AN could self-assemble into microspheres in aqueous solution with uniform sizes of750 nm in diameter,and was further cross-linked through photo-dimerization of the AN groups.The microgel of SA-hPtEA-AN is fluorescent and responsive to environmental stimuli such as temperature and pH,and can be used in the encapsulation and controlled release of guest molecules.In addition,the controlled release of guest molecules from the microgel of SA-hPtEA-AN can be monitored by its fluorescence change.Based on that,we preliminarily explored the co-assembling behavior of SA-hPtEA-AN and naphthalene diimides?NDI?in this dissertation.At first,we prepared NDI via one-step synthesis by the amidation of1,4,5,8-naphthalenetetracarboxylic dianhydride with Jeffamine?L-100.Then a series of microspheres were fabricated from co-assembly of SA-hPtEA-AN and NDI based on different mole ratio.With the increase of the content of SA-hPtEA-AN in reaction system,the size of microspheres increased,which will be helpful for researchers'exploration the relationship between the properties and the morphologies.In addition,because AN groups were?-electron rich species while NDI were?-electron deficient species,we imagined that there are charge transfer effects between them,and assemblies may show red fluorescence which is different from the green one belong to NDI and the blue one belong to SA-hPtEA-AN.However,the fluorescence was not apparent and the reason remains to be further explored.