Reversible thermochromic POSS-Metal Films for early warning

Abstract Due to the unique ability to change color promptly when temperature fluctuates, the reversible thermochromic film plays an important role in reducing the occurrence of fire accidents. It can be used into the early warning of fire and behaves as an indispensable part in constructing fire prevention system. In this paper, a series of novel reversible thermochromic POSS-Metal Films (abbreviated as PMFs) with different ratio of POSS (octa-aminopropyl POSS) and metal salt [Cr(NO3)3·9H2O] were prepared via a simple method. The PMFs not only exhibit excellent thermal-stability and repeatability, but also are capable of changing color rapidly within a few seconds as the temperature rises, possessing a superior warning effect of prompt color change. The thermochromic mechanism of PMFs is also elucidated by TG-MS, Variable temperature infrared test and Variable temperature X-ray electron diffraction, which explains its discoloration. With temperature increasing, ligands (H2O and NO3−) were decomposed and released from PMFs, resulting in the color change of PMFs. When the temperature decreased, the water molecules in the air could be captured into re-coordination with PMFs, making it recover its original color. The remarkable color change of PMFs makes it play an important role in the early warning of fire, providing us with a novel way in fire detection.