Preparation Of Hollow And Rattle-type Mesoporous Silica Nanoparticles And Their Applications In Catalysis And Drug Delivery

In recent years,the problem of human health and destruction of environment caused by environmental pollution has affect sustainable development of human society,while the emergence of nanotechnology has brought a new dawn.In virtue of their large specific surface area,tunable pore,high biocompatibility and easy to surface functionalization characteristics,nanomaterials have widely used as drug carrier or nano reactor in environment,new energy and biomedical fields.Among various nanomaterials,mesoporous silica nanoparticles?MSNs?are fascinating owing to their outstanding properties,such as excellent mechanical and thermal stability,low toxicity,easy modification and high biocompatibility.Besides,hollow and rattle nanostructures show many advantages,for instance,a tunable hollow cavity and easy to functionalization of core,thus attracting more attention.In this dissertation,we choose hollow and rattle mesoporous silica nanoparticles?HMSNs and RMSNs?as a research object.We design different structural silica spheres through self-templating method,and the synthesis process,formation mechanism and their applications in catalysis and biological field are systematically studied.The main contents are as follows:In the first part,we studied the preparation of HMSNs/RMSNs and their application in catalysis and biocompatibility.The hybrid silica spheres obtained from the co-condensation of TEOS and TSD are firstly synthesized via a modified Sto?ber method,subsequently undergoing a selective etching process in HF aqueous solution.After etching the inner section of hybrid silica spheres,the transformation can be carried out from solid spheres to hollow or rattle structures.In the solid-to-hollow conversion,it is found that the amounts of TSD play an essential role in the selective etching process.The CHN elemental analysis,Si MAS NMR spectra and TG results indicate that the component distribution of hybrid silica spheres is inhomogeneous,where the inner section has more organic groups,leading to the low density and easily be etched.Furthermore,we take full advantage of the inhomogeneity of hybrid silica and obtain the multi-shelled hollow/rattle silica spheres.Benefiting from the residual amino groups in HMSNs,Au@HMSNs composite can be further constructed by in-situ generating Au nanoparticles into their hollow cavity,which demonstrates an excellent catalytic performance for the reduction of 4-nitrophenol.Finally,the HMSNs samples also show a good biocompatibility.In the second part,we studied the preparation of RMSNs and their applications in adsorption and drug delivery.We firstly design a type of solid silica spheres with three different silica layers including the inner core of pure silica,the middle layer of hybrid silica,and the outer shell of CTAB/SiO₂ composite.Based on the structural differences in pre-designed silica spheres,the middle hybrid layer is preferentially etched away during the hydrothermal treatment in hot water,while the inner core and outer shell are relatively robust,resulting in the generation of rattle MSNs.Specially,the amount of CTAB play crucial role in the etching process,it is hardly to selective etching the hybrid silica layer at the absence of CTAB or use too much.By TEM?BET and the reaction conditions discussed,the hollow process was studied out.In addition,we also use rhodamine B?RhB?,A549 cells and ibuprofen?IBU?to investigate its adsorption,biological compatibility,drug delivery properties.Through above research,we have a further knowledge and understanding of the preparation process of HMSNs/RMSNs,influence factors,selective etching mechanism,catalytic performance and drug delivery etc.