Rewritable fluorescent platform and reusable hydrazine sensing thin film using aldehyde functionalized fluorophore integrated PMMA polymer matrix

Highlights: • Halochromic off-on fluorescence switching in solution as well as solid state. • Fabrication of rewritable fluorescence platforms. • Selective fluorescence sensing hydrazine. • PMMA based reusable solid fluorescence assay for hydrazine. -- Abstract: Triphenylamine (TPA) based di-aldehyde fluorophores have been synthesised and utilized for fabricating solid thin film fluorescence assay for hydrazine sensing and rewritable fluorescence platform. Addition of hydrazine reacts with aldehyde and strongly quenched the fluorescence intensity in solutions. Interestingly, fluorophores integrated into PMMA thin films showed strong blue fluorescence and exhibited turn-off fluorescence upon immersing in hydrazine solution (5%) and turn-on fluorescence by immersing in acetic acid (5%). Concentration dependent studies revealed the limit of detection (LOD) of 9.3–14.0 μM in solution and 0.021% by solid matrix. Reversible off-on fluorescence switching both in solution and PMMA matrix has been achieved by acid and base exposure that has been successfully used for demonstrating rewritable fluorescent platforms.