The general formula of cage silsesquioxane, POSS, for short, is (RSiO1.5) n, in which R is the group connected by eight vertex Si atoms, usually hydrogen, alkyl, aryl, alkenyl, halogen and so on. POSS has a clear three-dimensional structure, and its organic and inorganic groups are combined by the covalent bond. Therefore, POSS has the characteristics of inorganic/organic compounds and has good compatibility with organic polymers, so it can be used to construct polymer / POSS nanocomposites. Besides, the organic groups connected to Si atoms can be derivatized to prepare new POSS with different structures. Some POSS with active functional groups can be copolymerized with polymer monomers to prepare nanocomposites with excellent properties.
Figure 1. Three-dimensional structure of POSS.
Figure 2. Synthesis of POSS fluorescent microspheres.