RA C: Photonic Materials seeks to develop water-driven structured materials that can alter their electromagnetic properties in the optical and microwave ranges through water interaction. Depending on the wavelength of the electromagnetic radiation, we will change the effective permittivity of or scattering from structured media. This research aims to create adaptive surfaces, windows, and thermal insulation for sustainable architecture and garments, as well as customizable optical and microwave elements for adaptive optics, radars, and sensors. The focus is on understanding water’s electromagnetic properties at the interface of nanoporous media and controlling water distribution at nm- and μm-scales to achieve mechanically stable photonic materials activated by water.