Visual Monitoring Of Silica Growth And Surface Modification Based On Aggregation-induced Emission

As one of the most studied oxide-based nanostructured materials,Si O₂ has exhibited lots of advantages such as high colloidal stability,easy processability,excellent chemical inertness,controllable porosity and optical transparency.Therefore,Si O₂ has been widely used in in the filed of coating,drug delivery,catalyst carrier and hybrid materials.However,the high surface energy and rich hydroxyl groups make Si O₂difficult to be well dispersed in non-polar media,so that the surface modification is quite necessary for Si O₂ to adapt to more chemical environments.Both the synthesis and the surface modification of Si O₂ need characterization.For example,the morphology and size information can be obtained by scanning electron microscopy?SEM?,transmission electron microscope?TEM?,dynamic light scattering?DLS?,etc.The surface group information can be obtained by fourier transform infrared spectrometer?FT-IR?,X-ray photoelectron spectroscopy?XPS?and other characterization methods.However,these methods require periodic sampling from the reaction system before analysis.Some off-line analysis techniques require a long analysis period,which makes it impossible to timely monitor the growth and surface modification process of Si O₂.In this thesis,we developed a simple and fast in situ visualization method for monitoring the growth and surface modification of Si O₂based on the aggregation induced luminescence?AIE?technology,which has potential application value for the production and photo-functionalization of Si O₂.In this work,a fluorescent AIE probe?APTS-TPE?containing tetraphenylethylene group was first synthesized and then used as fluorescence probes to monitor the growth and surface modification of Si O₂.In order to investigate the potential application of Si O₂ with fluorescence properties,we studied the application of prepared AIE probe contained Si O₂particles in phase separation,hydrogel and magnetic response photonic crystal,respectively.?1?In this work,we prepared a silane based AIE probe?APTS-TPE?through the incorporation of?3-Aminopropyl?triethoxysilane?APTS?and tetraphenylethylene?TPE?,which was then used to in-situ monitor the growth process of Si O₂ in St?ber method.By adjusting the concentration of ammonia and TEOS,different sizes of Si O₂nanoparticles were obtained,and the relationship between Si O₂ particle size and PL intensity was discussed.?2?The prepared AIE probe was also used to monitor the surface modification of Si O₂ with APTS in toluene.Both the AIE probe and APTS can graft to the surface of Si O₂ particles,and the APTS amount on the Si O₂ surface can be monitored by PL caused by AIE probe.With the increase of APTS modified on Si O₂ particles,the PL intensity increased linearly,and the modified Si O₂ particles also exhibit AIE properties.?3?The potential applications of AIE Si O₂ prepared in this work were discussed as the using fluorescent Si O₂ particles as Pickering emulsion stabilizer,and the preparation of fluorescent hydrogel with surface modified Si O₂ nanoparticles.The AIE probe was also used to modify the surface of Fe₃O₄@Si O₂ nanoparticles,making the particles simultaneously have fluorescence emission and magnetic response photonic crystal property.