Light gold: a colloidal approach using latex templates

A new 18 karat light gold, composed of gold single crystals, amyloids, and a polymer latex matrix is developed. It is similar to a glassy plastic, yet lighter than aluminum and of use in watches, jewelry, radiation shielding, catalysis, and electronics. The material is prepared via a hydrogel precursor dried into an aerogel. Annealing of the polystyrene matrix under vacuum gives rise to a homogeneous template. The final apparent density and porosity of the material depend directly on the volumetric concentration of the starting solution used for hydrogel formation. After annealing, a homogeneous microstructure is obtained in which the shining gold single crystal platelets are evenly embedded in a polystyrene matrix. The material has a glass transition temperature of ≈105 °C which allows for annealing and molding above this temperature. A general scaling behavior is found for the Young's modulus of the material with the density. The Young's modulus of the material with a density of 1.7 g cm⁻³ is ≈50 MPa. The density and stiffness, as well as the color, of the material can be tuned depending on the final application.