Nanoparticle hybrid sunscreens

摘要

The invention discloses and claims a new class of chemical compositions with ideal sunscreen properties. The chemical composition comprises spherical particles between 200 nm and 10 microns in diameter prepared by an emulsion polymerization of tetraalkoxysilanes or organotrialkoxysilanes or organobridged trialkoxysilanes with a dye monomer bearing two or more alkoxysilyl groups attached to the bridging chromophore. The resulting spheres absorb ultraviolet light. The dye can be any organic chromophore capable of receiving multiple trialkoxysilyl groups resulting in multipoint covalent attachment that precludes leaching of the dye from the spheres. The formic acid-toluene-monomer emulsion polymerization allows for large-scale (>100 gram) synthesis of monodisperse particles under acidic, non-aqueous conditions without surfactants. The particles less than 1 micron in diameter are smooth as talc to the touch and will provide a smooth formulation for sunscreen creams or lotions.