Preparation And Properties Of The Poly(Zwitterionic Liquid) Nanomaterials

Because of their unique pendant-side chain structures, zwitterionic polymerspresent excellent chemical properties, preferable thermal stability and hydrationcapacity, especially “the anti-polyelectrolyte behavior in solution”, have attractedbroad attention in the world in recent years. Many novel and functional zwitterionicpolymers have been synthesized and stimulated great interest in many fields such asoil industry, biomedical materials, drugs synthesis and sewage treatment.On the other hand, polymer nanocapsules are of particular interest in recent yearsdue to their potential widespread applications in confined reaction vessels, drugcarriers, protective shells for cells or enzymes, transfection vectors in gene therapy,carrier systems in heterogeneous catalysis, dye dispersants and agents for wasteremoval etc. Controllability of their size, mechanical strength, permeability andbiocompatibility is of great significance for their applications and has thus triggeredtremendous research attention.In this thesis, intelligent poly(zwitterionic liquid) nanocapsules were first timeprepared via atom transfer radical polymerization (ATRP). With these producednanocapsules, a novel ion-response delivery system in which release profile is ionicstrength dependent has been successfully demonstrated based on their unique“anti-polyelectrolyte behavior”. It consists of three parts as follows:1. Novel core-shell hybrid nanospheres, with silica nanoparticles as core andcrosslinked PMAPSIm and PMBA as shell were prepared via surface-initiated ATRPpolymerization in the aqueous phase. After removal of the silica core, hollowpolyelectrolyte nanocapules were obtained. TEM, XPS, FT-IR and TGA resultsindicated that the hollow poly(zwitterionic liquid) nanocapules were successfullyprepared with the average shell thickness of ca.20nm.2. The application of hollow poly(zwitterionic liquid) nanocapules in ionic-strengthresponse release was successfully demonstrated using RhB as the probing molecule.The cytotoxicity of nanocapsules was evaluated in vitro using an MTT assay.Zwitterionic polymers exhibit good biocompatibility. The results imply it as an idealcandidate of targeted delivery, protective shells for cells or enzymes and gene delivery.3. PDMAEMA and PMAPSIm brushes were grafted onto wafer by atom-transferradical polymerization using initiator-modified surfaces. SEM, XPS, Ellipsometryresults indicated that the polymer brushes were successfully prepared.