Silsesquioxane nano-particles used for modifying properties of polymer hydrogels, and used to control X-ray contrasts. A combined X-ray and neutron scattering study

Organic-inorganic hybrid materials can be tailored to combine the advantages of organic polymers with those of inorganic components. An example is the design of a composite material obeying specific mecha-nical properties, light transmission factors and refractive index that makes it suitable for implant as intraocular lens. We have with this purpose studied a composite material composed of hydrophobically-modified poly(ethylene glycol) (HM-PEG) and polyhedral oligomeric silsesquio-xane (OCAPS) nano-particles, using combined neutron and X-ray scattering methods (SANS and SAXS). The OCAPS nano-particles are very well dispersed within water as well as within the polymer gel structure. The dispersion characteristics remain unchanged upon loading into the micellar structure, but the different contrasts factors of SANS and SAXS unambiguously show that OCAPS nano-particles are located within the whole gel-phase, except the micellar cores. The ideal dispersion within the aqueous phase makes silsesquioxane molecules ideal for controlled variation of the X-ray contrasts in small-angle X-ray scattering experiments as well as in X-ray imaging.