Reversibly photochromic wood constructed by depositing microencapsulated/polydimethylsiloxane composite coating

Photochromic wood was fabricated by coating microencapsulated photochromic material (MP)/polydimethylsiloxane composites onto wood using a simple drop-coating method. Urea-melamine–formaldehyde resin was used to microencapsulate the photochromic material (PM) via in situ polymerization. The concentration of the MP affected the photochromic property of the wood surface. The total color change (ΔE*) reached 82.2 when the concentration of the composite coating is 8%. Adhesion tests confirmed that the composite coating adhered firmly to the wood. This method is potentially useful for the production of functional wooden products, such as anti-counterfeiting materials and aesthetic wood.

Photochromism of Neutral Spiropyran in the Crystalline State at Room Temperature

Solid-state photochromic materials are very attractive due to their promising future in advanced functional materials with reversible and tunable optical properties. However, the development of photochromic material in the solid...

In-situ illumination with inelastic neutron scattering: A study of the photochromic material cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene (CMTE)

For the first time we successfully demonstrate in-situ illumination of a photochromic material during an inelastic neutron scattering (INS) experiment at cryogenic temperatures. cis-1,2-Dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene (CMTE) is a well-studied and commercially...

Electron transfer photochromism of solid-state supramolecules constructed by cucurbit[n]uril (n = 5-8) and 1-(4-carboxybenzyl)-4-[2-(4-pyridyl)-vinyl]-pyridinium chloride

Incorporation of the potential photochromic compound 1-(4-carboxybenzyl)-4-[2-(4-pyridyl)-vinyl]-pyridinium chloride (guest 1+·Cl-) into the macrocyclic hosts cucurbit[n]uril (n = 5-8, Q[n]) generated a new kind of photochromic material. 1H NMR experiments confirm...

Viologen-derived material showing photochromic, visually oxygen responsive, and photomodulated luminescence behaviors

A new 2D viologen-derived Zn(ii) photochromic material exhibits photochromic, visually oxygen responsive, and photomodulated luminescent behaviors.

Cooperative and Fully Reversible Photocatalytic Colour Switching Activation in Graphene-Copper-TiO2 Nanoparticles

<p>Nanostructured systems showing reversible colour switching are envisaged to play a significant role in photo-switches, photo-optical sensors, smart windows, displays, optical storage memories. Most of the materials exhibiting reversible colour switching are organic compounds. However, their UV-light activation, low thermal and chemical stability, as well as harmful synthesis methods, are of limit for their extensive use. In this research, we have created an inorganic switchable photochromic material exploiting: (i) TiO₂ ability of creating an exciton upon excitation, (ii) copper as the chromophore, and (iii) graphene’s extraordinarily high electron mobility. Our material showed itself to be able to work under visible-light, its photochromic property being three times faster than conventional titania based photochromic materials, reaching a stable change in colouration after only 30 mins of visible-light irradiation (<i>versus</i> > 120 min in conventional Cu-TiO₂). With the addition of just 1 wt% graphene, the material exhibited a staggeringly stable photochromic switching over repeated cycles. These results relate to the best previously reported values for any form of TiO₂-based photochromic material. This is therefore an excellent candidate for smart self-cleaning windows, and other chromic devices and applications.</p>

Cooperative and Fully Reversible Photocatalytic Colour Switching Activation in Graphene-Copper-TiO2 Nanoparticles

<p>Nanostructured systems showing reversible colour switching are envisaged to play a significant role in photo-switches, photo-optical sensors, smart windows, displays, optical storage memories. Most of the materials exhibiting reversible colour switching are organic compounds. However, their UV-light activation, low thermal and chemical stability, as well as harmful synthesis methods, are of limit for their extensive use. In this research, we have created an inorganic switchable photochromic material exploiting: (i) TiO₂ ability of creating an exciton upon excitation, (ii) copper as the chromophore, and (iii) graphene’s extraordinarily high electron mobility. Our material showed itself to be able to work under visible-light, its photochromic property being three times faster than conventional titania based photochromic materials, reaching a stable change in colouration after only 30 mins of visible-light irradiation (<i>versus</i> > 120 min in conventional Cu-TiO₂). With the addition of just 1 wt% graphene, the material exhibited a staggeringly stable photochromic switching over repeated cycles. These results relate to the best previously reported values for any form of TiO₂-based photochromic material. This is therefore an excellent candidate for smart self-cleaning windows, and other chromic devices and applications.</p>