Synthesis Of Thermo-responsive Mesoporous Silicon Carrier Material And Its Property

With the development of science and technology, modern materials are constantly to develop in the direction of high performance and multi-function. Among them, the intelligent materials have become one of the research hotspots. Intelligent material is a material that can judge and produce appropriate response behaviors to the external stimuli. Under environmental stimuli, corresponding changes in the structure, physical and chemical properties of the intelligent materials occur. In both biomedical and catalytic reaction, the temperature is extremely important and easy to realize control condition. Therefore, temperature responsive polymers are one of the most widely studied in intelligent materials. We have prepared thermally responsive mesoporous silicon carrier material by using poly(N-isopropylacrylamide) as the temperature sensitive phase and the inorganic mesoporous material as substrate material.Firstly, mesoporous silica nanoparticles(MSNP) with unqiue properties was prepared through a sol-gel reaction. Utilizing an electron transfer activation and regeneration of atom transfer radical polymerization(ARGET ATRP),thermoresponsive PNIPAm long chains were grafted onto the surface of MSNP to get the thermally responsive mesoporous silicon carrier material which can be switched“on” and “off” by temperature variation. We also did several analysis tests to study the samples. Methylene blue, as drug model, has been used to study the release performance of thermally responsive mesoporous silicon carrier material under different temperature, and the sustained release behavior was also studied by switching the solution temperature. Meanwhile, Ritger-Peppas equation was used to study the drug release kinetics and the mechanism of release of thermally responsive mesoporous silicon carrier material.Then, the thermally responsive smart nanoreactor was prepared by using metal nanoparticles as catalyst and thermally responsive carrier materials as the composite function layers. Debye-Scherrer equation was used to calculate the average particlesize of Ag nanoparticles to be about 12 nm. It can change according to the change of external temperature, namely, the reversible extending and shrinkage of the polymers chains upon the temperature change induced the corresponding switchable “on/off”variation. When the temperature is above the LCST of PNIPAm, the polymer chains curled to a roll, so that it resulted in the difficult access of reactants to Ag nanoparticles and displayed a weak catalytic activity. On the contrary, below the LCST of PNIPAm, the polymer chains changed to an extended strip so as to easy access of reactants to Ag nanoparticles and a high activity. The smart nanoreactor can exhibit the reproducible ability to repeat the switchable catalytic activity with variation of temperature.Here, in biomedicine, thermally responsive mesoporous silicon carrier material had good controllable release of drug with the temperature change. In catalytic reaction, the thermally responsive smart nanoreactor was comprised by thermally responsive mesoporous silicon carrier material containing Ag nanoparticles. It was indicated a tunable catalytic ability controlled and the reproducible ability by its temperature responsive shape change.