Research On Constructing Spatially Controllable Silicon Oxide Mesoporous Structures Using Reversible Bonding

Mesoporous silicon oxide particles are one of the most promising inert carriers.And as their applications deepen,it is necessary not only to achieve precise regulation of the size of silicon oxide mesopores but also to find effective design and preparation paths to achieve multifunctional or intelligent external response of mesoporous structures for more complex usage environment.In this paper,we attempt to construct a responsive controlled release system by introducing reversible borate ester bonds in the main body of mesoporous silica based on reversible bonding that can respond to external stimuli.The main contents are as follows:（1）Borate ester bonds were introduced into silicon oxide hollow spheres in a co-growth manner.This approach allows the direct introduction of boric acid or phenylboronic acid and tannins into the main body of the silicon oxide,which has a great impact on the pore structure.Among them,the addition of phenylboronic acid during the preparation process had the greatest effect on the structure of the silicon oxide hollow spheres,making the structure more sparse and porous,with the pore size increasing to 15 nm and the specific surface area and pore volume more than twice as large.（2）Boronic ester bonds were introduced into mesoporous silicon oxide nanoparticles using grafting method.The dendritic mesoporous silicon oxide nanoparticles DMSN with central radial pore structure were used as the main body and grafted with phenylboronic acid on the inner and outer surfaces of the nanoparticles through surface modification.Boronic acid ester bonds formed by phenylboronic acid and polymers containing cis-diol bonds are used to regulate different pore sealing states and to construct loaded silica systems based on boronic acid ester bonds.（3）The controlled release model of mesoporous silicon oxide nanoparticles was investingated using the responsiveness of borate ester bonding.By examining the release behavior of the samples under different external stimuli,it was verified that the mesoporous silica constructed based on borate ester bonds has a controlled release behavior in response to the p H value and the concentration of H₂O₂.The pore blocking effect produced by borate ester polymers of different molecular weights is also used to achieve the modulation of the release rate of the loaded molecules.