Triphenylamine derivatives functionalized di-ureasil hybrids for information encipherment

Abstract

Realizing information protection in low cost and large-scale fabrication still casts tough challenges in various aspects primarily involving material synthesis and engineering. Herein, to circumvent these challenges, the method of reversible protonation reactions of triphenylamine (TPA) derivatives grafted with pyridyl groups is intentionally introduced into the di-ureasil hybrids to functionalize the materials with targeted features. The results reveal that the reversible protonation reactions are still observed after homogenously distributing the TPA derivatives into the di-ureasil hybrids because of the organic-inorganic skeleton structure supplying the channels for the penetrations of NH3·H2O and HCl molecules, leading to an obvious emission color switch between red and cyan-green. Moreover, by replacing the pyridyl group with the pyridinium group in a similar molecule structure, the TPA derivatives are able to achieve an eye-cheated optical performance with very closing UV-Vis and emission spectra but lose the stimuli responsive optical performance. Capitalizing on the special features, the strategies designed for information encipherment applications based on the TPA derivatives functionalized di-ureasil hybrids were estimated through direct coating or preparing the inks for the fountain pens to write. This work successfully endows values of the as-synthesized TPA derivatives for the particular application. To compare with the most analogous powder materials applied for information protection applications, the portable security inks show a bright future for commercial applications offering simple operation, easy visual detection, and large-scale fabrications. In addition, the di-ureasil hybrids doped with TPA derivatives also present good performance as warming white-light-emitting films, showing potential for light electronics’ displays.

Keywords

• Triphenylamine derivatives
• Sol-gel techniques
• Protonation reaction
• Information encipherment