title: Mechanochromic photonic gels.
abstract: Polymer gels are remarkable materials with physical structures that can adapt significantly and quite rapidly with changes in the local environment, such as temperature, light intensity, electrochemistry, and mechanical force. An interesting phenomenon observed in certain polymer gel systems is mechanochromism - a change in color due to a mechanical deformation. Mechanochromic photonic gels are periodically structured gels engineered with a photonic stopband that can be tuned by mechanical forces to reflect specific colors. These materials have potential as mechanochromic sensors because both the mechanical and optical properties are highly tailorable via incorporation of diluents, solvents, nanoparticles, or polymers, or the application of stimuli such as temperature, pH, or electric or strain fields. Recent advances in photonic gels that display strain-dependent optical properties are discussed. In particular, this discussion focuses primarily on polymer-based photonic gels that are directly or indirectly fabricated via self-assembly, as these materials are promising soft material platforms for scalable mechanochromic sensors.
authors.affiliation: Materials Science and Engineering Division, National Institute of Standards and Technology, 100 Bureau Drive, MS 8542, Gaithersburg, MD 20899, USA. edwin.chan@nist.gov
authors.forename: Edwin P
authors.initials: EP
authors.lastname: Chan
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Walish
authors.forename: Augustine M
authors.initials: AM
authors.lastname: Urbas
authors.forename: Edwin L
authors.initials: EL
authors.lastname: Thomas
mesh_terms: D004867:Equipment Design; D005782:Gels / Q000737:chemistry* / Q000528:radiation effects*; D008027:Light; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D017785:Photons; D013314:Stress, Mechanical; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D014159:Transducers
chemical_list: D005782:Gels
keywords: block copolymers; gels; mechanochromism; photonic crystals; stimuli-responsive materials