Fine-tuned gel particles enable smart windows for energy efficiency. Polymeric gel particles have been used to make windows that highly effectively allow or block heat-generating wavelengths of sunlight in response to temperature. Such windows might increase the energy efficiency of buildings.

See the source article by following the link below:
Fine-tuned gel particles enable smart windows for energy efficiency. Polymeric gel particles have been used to make windows that highly effectively allow or block heat-generating wavelengths of sunlight in response to temperature. Such windows might increase the energy efficiency of buildings.