Demonstration of temperature-sensitive paints with rigorously controlled thickness applied to variously shaped metal substrates with a highly stable connection based on a demulsification-induced fast solidification strategy

Abstract

Large area and mechanically stable temperature-sensitive paints (TSPs) with excellent temperature sensing properties are highly desired by industry for temperature measurement applications. Along these lines, a novel compound of TSPs composed of WPU/PCD/Eu(DBM)₃Bipy (WPU: waterborne polyurethane, PCD: waterborne polycarbodiimide, DBM: dibenzoylmethane) was fabricated on a pure zinc (Zn) substrate by employing the demulsification-induced fast solidification method. On top of that, the luminescent molecular probe of Eu(DBM)₃Bipy was in situ dispersed into the WPU/PCD emulsion. The thickness of the TSPs was rigorously controlled within micrometers. The TSPs can be employed based on the principle of temperature quenching for the detection of temperature change from the range of 25 °C to 85 °C. Interestingly, the highest temperature sensitivity of TSPs with 4.46 wt% Eu(DBM)₃Bipy reaches the value of 48.34 × 10⁻³ °C (65–75 °C). Moreover, the WPU/PCD/Eu(DBM)₃Bipy TSPs can be used twice without observing a reduction of the fluorescence emission intensity. In addition, the proposed TSPs exhibit excellent impact resistance (at 100 cm height and 1 kg weight) and stable mechanical connection with the Zn substrate.