Acidochromic anticounterfeiting inks and smart sensors from azobenzenecontainingpolymer particles

N,N-dihydroxyethyl azobenzene can be used as a very desirable dye with different colorchanges in neutral and acidic environments. The visible light absorption peak of N,Ndihydroxyethylazobenzeneshowed that the absorption maximum λ shifts from 435 to 535 nm withdecreasing pH from 6 to 1, which is accompanied by a distinct color change from yellow to pink .This phenomenon is called acidochromism, which is due to the conversion of the diazo structure tohydrazone by absorbing hydrogen from an acidic stimulus. On the other hand, diazobenzene wasdoped on poly(methyl methacrylate) latex nanoparticles prepared through emulsifier-free emulsionpolymerization in the presence of HEMA comonomer. Azobenzene dye doping on polymerparticles increases the intensity of absorption due to the placement of the smart compound on thesurface of polymer particles and the maximum efficiency of acidochromism.

Acidochromic anticounterfeiting inks and smart sensors from azobenzenecontainingpolymer particles Keywords:

Azobenzene smart dye , acidochromism , doping , smart sensors , emulsifire-freeemulsion polymerization.