Patent ID: 7691325

Claim:
A method of manufacturing a vapor-sensing device, comprising: placing an aqueous dispersion of colloidal spheres on a substrate; drying the aqueous dispersion of colloidal spheres to obtain a colloidal crystal; filling the voids among the colloidal crystal with a crosslinked vapor-expandable matrix composition having a 2% to 5% crosslinking density; curing the vapor-expandable matrix composition; and peeling away any excess vapor-expandable matrix material from the surface of the film, wherein the colloidal crystal is exposed wherein: the vapor-expandable matrix comprises a composition that reversibly swells in the presence of at least one type of vapor, the composition selected from the group consisting of: hydrogels, polydimethylsiloxane (PDMS), styrene-butadiene rubbers, nitrile rubbers, butyl rubbers, halogenated butyl rubbers, chloroprene rubbers, N-isopropyl acrylamides (NIPAMs), polyvinyl alcohols (PVAs), polyethylene oxides (PEOs), and polyethylene glycols (PEGs); the colloidal crystal exhibits Bragg diffraction; and at least one surface of the colloidal crystal is exposed directly to the environment.