| Mesoporous silica nanoparticles are accompanied by a series of problems in development.In order to make them applicable in medicine,the size of the pore size is critical.Therefore,the realization of pore size modulation needs further research,and achieving its biocompatibility,particle size reduction is especially important.In this study,mesoporous silica nanoparticles with different morphologies and mesoporous structures were prepared by using the modified Stober method with CTAB as a template,and the influencing factors were explored from different aspects.The process and synthesis mechanism of mesoporous silica nanoparticles were explored mainly from the aspects of the amount of templating agent,reaction temperature,reaction time,alcohol-water ratio and hydrolysis rate of TEOS.The optimal parameters were determined by comparative analysis in order to improve the dispersibility and pore structure of mesoporous silica nanoparticles,increase their specific surface area,and increase the pore size to improve the loading capacity of the drug.The research work of this thesis has guiding significance for regulating the pore structure,preparation method and application of mesoporous silica nanoparticles.In the first part of this work,mesoporous silica nanoparticles were prepared by soft template method and tetraethyl orthosilicate(TEOS)as silicon source and the results show that:(1)When TMB or a mixed solution of ethanol and sulfuric acid is used as a pore-enlarging agent,it can play a role in the pore regulation of mesoporous silica nanoparticles.(2)Changing the percentage of ethanol added during the preparation process can effectively adjust the size of mesoporous silica nanoparticles,and the effect of mesoporous silica nanoparticles prepared by using ethanol and sulfuric acid as pore-expanding agents It is equivalent to the effect of particles prepared by TMB as a pore-expanding agent.The structure parameters of the best mesoporous silica nanoparticles after swelling are:SBET=502.18 m2·g-1,Vtotal=0.69 cm3·g-1,D?=2.2 nm,D?=10.4 nm.(3)Mesoporous silica nanoparticles are prepared by using isopropanol as a solvent.and a mixed solution of ethanol and sulfuric acid is still suitable as a pore-expanding agent,which also can change the pore structure of the particles and function as a pore-expanding.The structure parameters of the best mesoporous silica nanoparticles after swelling are:SBET=782.0 m2·g-1,Vtotal=0.96 cm3·g-1,D?=2.2 nm,D?=5.9 nm.(4)In addition to the involvement of hydrogen ions in the pore-expanding behavior,sulfate ions are also involved in the regulation of mesoporous pores.The second part of this work,mesoporous silica nanoparticles were prepared by using triethanolamine(TEA)as a basic catalyst and cetyltrimethylammonium bromide(CTAB)as a template and the results show that:(1)Mesoporous silica nanoparticles with different particle sizes can be obtained by changing the amount of ethanol in the preparation process,wherein when the amount is 7.5%to 10%,nanoparticles having uniform dispersion and uniform particle size and no impurities can be obtained,and the average particle diameter is 45?60 nm.When the amount is 0 to 5%,the obtained nanoparticles have a small particle size and an average particle diameter of 40 to 50 nm.(2)When the amount of ethanol added was 7.5%and the pore expansion time was 48 h,the pore structure parameters of the obtained mesoporous silica nanoparticles were as follows:SBET=319.7 m2·g-1,Vtotal=0.53cm3·g-l,D?=2.7 nm.(3)Mesoporous silica nanoparticles can be synthesized under weakly basic conditions.Although the use of ethanol and sulfuric acid as the pore-enlarging agent can increase the pore size and improve the uniformity,the range of pore diameter improvement is limited.Increasing the pH value during the preparation of mesoporous silica nanoparticles prepared by TEA/CTAB system is beneficial to the process of swelling,and is more conducive to the change of the structure and morphology of the nanoparticles by the pore-enlarging agent. |
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