Preparation,Self-Assembly Of N-Substitued Acrylamide Nanogel For Photonic Crystal And Its Application

Nanogels are nanoscale hydrogels that combine both properties of hydrogels and nanomaterials.Nanogels are similar to hydrogels,with high water content,flexible and adjustable chemical and physical structures,good mechanical properties and biocompatibility.But different from hydrogels,since the size of nanogels is much smaller than that of bulk hydrogels,which has advantage that large hydrogels do not have.The most prominent advantage is that nanogels respond to environmental stimuli more quickly than bulk hydrogels.In addition,nanogels have the advantages of low viscosity,good controllability of preparation and further self-assembly.Generally,hard colloidal particles(such as silica,polystyrene,etc.)can form an ordered structure similar to a crystal structure,named a photonic crystal.The assembly of nanogels is similar to that of hard colloidal particles,but the nanogels have responsiveness combined with photonic crystal structure.Due to the properties of softness and the unique stimuli responsiveness,nanogels show more interesting assembly behaviors.The lattice parameters of a photonic crystal change under the corresponding physical or chemical conditions,and the color change of the material can often be observed directly by the naked eye.Novel optical sensors can be designed using these special optical phenomena of soft colloidal crystals and their stimuli responsiveness.At present,the research of the preparation of photonic crystal structures of hard sphere colloidal particles is more in-depth,but the research on photonic crystal preparation of soft sphere nanogels is relatively rare.Most of the research in this aspect focuses on the formation of inverse opal structure of hard spheres,and there are problems such as long preparation period,unsuitable control of monodispersibility of nanogel,difficulty in rendering and immobilization of nanogel structure color,etc.In view of the above research status and development bottleneck,in this paper,a series of Nsubstituted acrylamide copolymer temperature-sensitive nanogels were studied by means of classic precipitation emulsion polymerization.The work focuses on preparation of nanogels,various types of responsiveness,self-assembly and immobilization of photonic crystals and related biological applications.The specific content is as follows:1.Non-ionic temperature-sensitive nanogel poly(N,N-diethylacrylamide/N,Ndimethylacrylamide)(P(DEA-co-DMA)with high content of hydrophilic monomer N,Ndimethylacrylamide(DMA)was prepared by precipitation emulsion polymerization.The preparation was achieved successfully by means of extremely low initiator dosage.A series of nanogel concentrates with structural color were prepared by high temperature hydrophobic evaporation based on its good monodispersity.The effects of the monomer DMA introduction and polymer concentration on this structure color were investigated.The more DMA or the lower the polymer concentration,the red shift of its reflection spectrum.Based on the high DMA content of the hydrophilic monomer introduced,the anti-adsorption performance of a series of hydrophilic nanogels on lysozyme and cytochrome c was investigated.2.(N,N-diethylacrylamide/Acrylic acid)(P(DEA-co-AAc))was prepared by precipitation polymerization.According to the preparation idea in CHAPTER 2,AAc content was successfully introduced to 40 wt% by means of extremely low initiator dosage,and what still maintained good monodispersity.Based on its good monodispersity,the nano-gel microspheres were self-assembled with photonic crystals.At the same time,external disturbances were used to make the nanogel microspheres into the short-range ordered state again.The macroscopic hydrogels with structure color,elasticity and temperature /p H dual response were prepared by the method of optical crosslinking.Based on the high AAc content,the effect of a series of hydrophilic nanogels on the adsorption and neutralization of melittin was investigated.The hemolytic test of melittin was carried out by fetal bovine erythrocytes,and nanogels were used as "plastic antibodies" to investigate the adsorption and neutralization effect of nanogels with different monomer ratios and different particle sizes.3.Using precipitation polymerization,N-hydroxyethylacrylamide(HEAA)containing hydroxyl was introduced to prepare poly(N-isopropylacrylamide/N-hydroxyethylacrylamide)(P(NIPAMco-HEAA))temperature-sensitive nanogel.A series of monodisperse nanogels with different particle sizes,crosslinking degrees and monomer components were prepared from four synthetic factors including monomer content,emulsifier dosage,initiator dosage and crosslinking agent dosage.Based on the introduction of HEAA containing hydroxyl,the nanogel concentrate with structure color was immobilized by chemical crosslinking to prepare macroscopic hydrogels with structure color,elasticity and temperature responseness.We try to immobilize the gel by the method of photoinduced immobilization.Based on its good monodispersity,the nanogel microspheres were self-assembled by photonic crystals in batches,and the different temperature points and solution concentrations required for crystal growth were explored.4.Using precipitated polymerization,N,N?-bis(acryloyl)cystamine(BAC),a cross-linking agent containing disulfide bond,was introduced to prepare the oxidative reductive / temperature-sensitive nanogel(N-isopropylacrylamide/N-hydroxyethylacrylamide)(P(N-isopropylacrylamide-ss-Nhydroxyethylacrylamide))(NP-BAC).At the same time,a comparative sample(NP-BIS for short)was prepared by changing the type of cross-linking agent only to N,N?-methylene-bis-acrylamide(BIS).The difference between temperature sensitivity and reducibility of NP-BAC and NP-BIS nanogels was investigated.Based on the reduction response,Propranolol was used as a model drug to study the drug release behavior of nanogels by DTT in different concentrations.Based on the work of structural color nanogels and their immobilization into hydrogels in CHAPTER 4,the response of NP-BAC and np-bis nanogels and their photonic crystal hydrogels to temperature and reduction was compared.The cytotoxicity of NP-BAC nanogel was studied.It is non-cytotoxic and can be used as an alternative material for optical biosensors or nanomedicine for enhancing drug delivery.