Bulk silicone nanocomposites with thermoresponsive optical behavior were fabricated using silica nanoparticle fillers within a cross-linked silicone matrix. Silica nanoparticles (25 nm diameter) were surface-modified, allowing for even distribution at 6-24 wt % within and covalent bonding to the silicone matrix. Utilizing the temperature-dependent match/mismatching of the refractive indices of the silica nanoparticle filler and the silicone matrix, bulk nanocomposites are highly transparent at room temperature and demonstrate significant increases in opacity with increasing temperature up to 100-150 °C. Such a response could be cycled quickly and repeatedly with no detrimental effect on the material.
