Tungsten blue colloidal

The dark-blue, colloidal (W 020H)XW 03)i-4, Tungsten Blue , arising in an HCl mixture of with a little H28 or 8O2 provides an excellent test for tungsten or reductants ... 

The colloidal solution may also be prepared by dissoh-ing tungsten tetrachloride in alcohol and ether (equal volumes) and then diluting with alcohol and water. The solution obtained acts as a positive colloid and coagulates immediately when small quantities of neutral salts, hydroxides, or strong acids are added. On passing an electric current through the solution, a deep blue precipitate separates at the cathode. ... 

Electrochromic devices have also utilized LbL assembled films for immobilizing the active electrochromic material that changes color at an applied voltage. Polyviologen (PV) was the first active material that was used for such purposes within PV-PSS multilayers, while the first LbL-based solid-state electrochromic device utilized poly(3,4-ethylene-dioxythiophene) (PEDOT) colloid as the electrochromic material within multilayers of PEDOT/PSS and polyaniline. Other nanoparticles were used for the development of electrochromic devices with LbL films, such as Pmssian blue, polyoxometalate, and tungsten oxide. A recent example demonstrated the use of coordination chemistry-based LbL assembly to fabricate fast-switching electrochromic films of zinc polyiminofiuorene and terpyridine. ... 

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