Silsesquioxanes (SQs) are organosilicon compounds with an oxygen to silicon ratio of 1.5 and these polymeric structures can be represented as (R-SiO1.5)n (n = even number). We have developed a facile method for the synthesis of functional silsesquioxane nanoparticles (SQ-NPs) based on the hydrolytic co-condensation of bulky functionalized triethoxysilane precursors. Using this approach, we have successfully synthesized hydroxyl-functionalized, cationic, sulfur-containing, fluorinated, and amphiphilic SQ-based hybrids. These SQ-NPs are amorphous hybrids composed of various species having 6–18 Si atoms. They exist as complete and incomplete cage-like structures, which have various functional groups. This enables the development of novel amorphous SQ-based hybrids with relatively low viscosity, good miscibility, tunable solubility, high refractive index, and good thermal properties.
We have also focused on the preparation of dual-functionalized SQs that are recognized as attractive hybrids for the next-generation smart coatings and UV-induced nanoimprinting materials. These SQs contain two or more different organic groups that are covalently bound to an inorganic core. Recently, we designed self-healing hybrids with tunable flexibility and healing properties using dual-functionalized SQs complexed with metal salts.