Our results show that although both of the two kinds of nanoparticlespossess favourable properties for loading and releasing drugs, themesoporous silica nanospheres perform better in dispersity andcontrolled release than the nanorods, which probably endow them thepotential as incellular drug delivery system.
In order to solve this problem, surface modification techniques are applied to improve the interaction between the nanoparticles and the polymer. In the work of Yuan , in order to prepare the silicone rubber with high thermal conductivity, pristine and surface-modified ZnO nanoparticles containing the vinyl silane group are incorporated into the silicone rubber via a hydrosilylation reaction during the curing process. The corresponding structure, morphology and properties of the silicone rubber/ZnO (SR/ZnO) and silicone rubber/SiVi@ZnO (SR/SiVi@ZnO) nanocomposites were investigated. Yuan synthesized ZnO nanoparticles (with an average size below 10 nm) by a sol-gel procedure. Next the silicone coupling agent VTES was successfully incorporated onto the surface of the nanoparticles. The SR/SiVi@ZnO nanocomposites showed better mechanical properties and higher thermal conductivity due to the formation of a cross-linking structure with the silicone rubber matrix and better dispersion in that matrix.
For the synthesis of mesoporous silica nanoparticles ca
Poly(methyl methacrylate) was also used as a ZnO surface modifier by Hong . Nanoparticles of zinc oxide with a diameter of approximately 30 nm were synthesized by means of homogeneous precipitation followed by calcination. In order to introduce reactive groups onto the ZnO surface, a reaction was carried out between the hydroxyl groups and a silane coupling agent (3-methacryloxypropyltrimethoxysilane). Graft polymerization was effected by means of a reaction between the ZnO, containing silanol groups, and the monomer. Tests showed that the polymerization does not alter the crystalline structure of the ZnO nanoparticles. Their dispersion in the organic solvent can greatly improve the graft polymerization of PMMA, and further improvement can be achieved by the addition of other surfactants. Modification of ZnO nanoparticles by grafted PMMA increases the degree of lyophilicity of the inorganic surface and reduces the formation of aggregates. The work of Hong , showed that ZnO nanoparticles grafted with PMMA can increase the thermal stability of polystyrene.