Innovative Color-Shifting Polymerized Crystalline Colloidal Array Paints and Coatings

University of Pittsburgh researchers have developed a film-forming crystalline colloidal array paint and coatings that Bragg diffract light in the visible and NIR spectral regions. These paints are comprised of highly charged polystyrene spheres, co-solvents, film-forming monomers, and additives. Upon curing, the paint transforms into a dry polymerized crystalline colloidal array that Bragg diffracts light according to the spacing between the ordered polymeric spheres. These materials can find practical applications as color-shifting coatings, filters, and diffracting paints.

Description

The invention involves a new film-forming paint that Bragg diffracts light in the visible and NIR spectral regions. The paint is comprised of highly ordered crystalline colloidal arrays of highly charged polymer spheres that self-assemble and maintain their diffraction in the presence of different paint ingredients. This process relies on a new emulsion polymerization process yielding highly charged polymeric spheres, which enables the stability and self-assembly of the spheres in the presence of other paint ingredients. Upon curing, the paint forms a highly ordered polymerized crystalline colloidal array that Bragg diffracts light.

Applications

- Color-shifting paints and coatings
- Filters
- Sensing materials
- Cosmetics

Advantages

This paint offers several advantages over standard paints. It is a color-shifting paint, meaning the color changes with the angle of view. Changing the particle size of the crystalline colloidal arrays in the paint allows control over the diffracted color. A layer of less than 10µm is needed to diffract all the light that hits the surface. This paint is less expensive and provides higher diffraction efficiencies compared to other technologies. The highly charged spheres are stable in water and UV radiation, making the paint stable in both wet and dry states.

Invention Readiness

The invention is at the stage where highly charged monodisperse colloid synthesis, paint formulation development, and application and curing by thermal and UV mechanisms have been achieved. The paint has been successfully applied and cured to form highly diffracting coatings.

IP Status

https://patents.google.com/patent/US20080108730A1