Preparation And Applications Of Perfusive Silica Microspheres

monolith is characterized by the presence of hierarchicalmacro/meso/microporous structure. The macropores in the material arethree-dimensionally connected and penetrable through the particles. whichcan contribute much to accelerate the mass transfer within the materials. Theskeletons possess numerous meso/microporous which guarantee high surfacearea of the material. They have found wide applications in efficient energystorage, fast separation and preparation, high-throughput removal ofenvironmental pollutants, high efficient catalysis, etc. However, the big sizeof silica monolith made it difficult to be modified with the functional moieties,difficult to be packed into column, which restraint its applicationdramatically.Based on these observations，synthesis of perfusive materials whichpossess the excellent porous structure as the monolith can improve thematerials’ performance and expand its applications area. The main work islisted as follows：（1）Aseries of perfusive silica materials with different sized macroporesand mesopores were synthesized with sol-gel method and derivatized withhydrophobic moieties of octyl or octadecyl to investigate their drug deliverybehavior. Nimodipine, as a hydrophobic drug model, was used in theinvestigation. It is found that the drug-loading amount increased with theincrease in the mesopore sizes of the carriers. The in vitro release studiesdemonstrate that both enhanced release and sustained release can be achievedon the proposed materials. Moreover, the release speed can be controlled bythe macropore sizes or surface characteristics of the materials.（2）A carbon material was synthesized using the silica particle as atemplate, and it has been attempted to be an electrode material for a fastrechargeable electrochemical double layer capacitor （EDLC）. Though thesurface area is only826（±2） m²g^-1and a large quantity of micropores exist, the capacitance of the EDLC can reach as high as170（±1） F g^-1regardless ofthe cyclic voltammetry scan rate. Furthermore, it is noteworthy that themicropores in the carbon show no obvious detrimental to the performance ofthe EDLC. The favorable performance would be ascribed to the super poreopenness and good pore connectivity of the carbon material.（3） Silica microspheres have been synthesized by phase separation andsol-gel transition coupled with emulsion method. their preliminaryapplications as HPLC packings in fast separation and low-pressure separationhave been attempted in the present study. Benzene, benzaldehyde and benzylalcohol were separated within two minutes on the silica column at a flow rateof7mL min-1. Vitamin E mixtures can also be baseline separated at a highflow rate of8mL min-1. In addition, thirteen aromatic hydrocarbons werewell separated on the octadecyl-bonded silica （ODS） column. In comparisonwith a commerical Kromasil ODS column, the pressure of the proposedcolumn is much lower （<1/2） under the same chromatographic conditions,while comparable separation efficiency can be achieved.