| Multi-functional intelligent materials with photochromism,latent heat energy storage and thermo-regulated have attracted wide attention,which have broad application prospects in the field of smart clothing,building materials,wearable intelligent sensors and so on.Organic/inorganic composite shell MF/Si O2 microcapsule prepared by in-situ polymerization was designed to obtain a phase change material with excellent thermal density and thermal stability.Choose n-octadecane as the core material,and use melamine-formaldehyde resin as the hard template to hydrolyze ethyl orthosilicate(TEOS)to synthesize the shell material of the microcapsule.Firstly,the optimum hydrolytic conditions of TEOS to form microcapsule shell materials were explored.At p H values of 2 and 11,through thermal field emission scanning electron microscopy(FE-SEM)can know that microcapsules with an obvious core-shell microstructure were successfully fabricated.The influence of the ratio of MF/TEOS on the morphology and performance of the microcapsules was studied.When the optimal ratio of MF/TEOS was 1:1,the average particle size of MF/Si O2 microcapsules was 2.41?m,with uniform distribution and good surface morphology.The results of chemical analysis and structural characterization showed that MF/Si O2 microcapsules with obvious core-shell structure were successfully prepared.The prepared microcapsules can not only store and release a large amount of latent heat through phase change,but also have good phase change reliability,cycle durability and sealing performance.The thermal conductivity of MF/Si O2 microcapsules is raised to 30.05%via comparing with original microcapsules.In this chapter,octadecyl acrylate was used as the matrix material to introduce spiropyranoid photodye and the photochromic nanoparticles were prepared by the method of miniemulsion polymerization.The average particle size of photochromic nanoparticles is 200-300 nm,and the particle size is uniform.The surface of MF/Si O2microcapsules was modified by using silane coupling agent(ATPES),and photochromic phase change microcapsules were successfully prepared.The chemical structure analysis fully proved that PSA successfully immobilized the surface of MF/Si O2 microcapsule.And the analysis of its heat storage performance shows that it still has high energy storage performance.Through 100 heating and cooling cycles,it was found that the latent enthalpy of photochromic phase change microcapsules fluctuated within a small range around 148.2 J/g.This dual-function organic/inorganic composite shell photochromic microcapsule is expected to have a wide range of applications in thermal energy storage,thermal management,transportation and so on. |
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