Facile nanoparticle dispersion detection in energetic composites by rare earth doped in metal oxide nanostructuresElectronic supplementary information (ESI) available: XPS spectra of the powder samples, SEM images of agglomerate powder and size distribution, video of confocal 3-Dimensional stack rotation, UV-visible spectra of powder samples, and additional digital image analysis of bulk samples. See DOI: 10.1039/c5ra10659a

The segregation and agglomeration of nanoparticles dispersed in polymer matrices play important roles in nanocomposite performance. A method of rapid and simultaneous visualization of macroscopic and submicron particle dispersion properties is presented, based on nanoparticle luminescence induced by europium doping. The luminescence intensity of polymer composites containing Eu-doped TiO 2 nanoparticle catalysts varied with the nanoparticle agglomerate size between 90 nm and 10 μm, and with concentration variations from segregation. These variations were detected by photoluminescence spectroscopy and visible-light photography, making this a facile characterization method for bulk composites without affecting the nanoparticle performance. Visible-light method utilizing consumer grade digital photography to characterize the dispersion properties of metal-oxide nanoparticles in a polymer matrix.