Novel Fluorescent Polyurethane Coating on Fabric with Acid‐Base Indicating Function in Solution

Abstract

AbstractThe preparation of multifunctional composite materials with maximum fluorescence emission is an ideal choice to replace fluorescent dyes. We synthesized a series of novel fluorescence polyurethane (FPU) films. The effect of different contents, different solvents and different pH on the fluorescence intensity were investigated in detail. In accordance with increasing proportion of 2, 7‐Dichlorofluoresce (DCF) in the FPU, the emission peak exhibit a gradual bathochromic shift and the fluorescence intensity show a trend of increasing first and then decreasing. The strong fluorescence emission of the obtained fluorescent film is in the range of about 570 nm. The maximum fluorescence intensity is 842, and the reflectance of the film is 21 % with a bright yellow at this time. In addition, acid‐base response fluorescence emission performance are endowed the fluorescent polyurethane film in the solution state. Different luminous intensities are emit by the film solution samples in near neutral (540 nm, yellow‐green light) and alkali (580 nm, orange‐yellow light). The maximum displacement exceeds 40 nm. Compared near neutral (pH=7) to alkaline (pH=12) environmental, the fluorescence emission intensity is increased by 1800 % (from 90 increasing to 1680). By establishing the relationship between the concentration and the fluorescence emission intensity, the fluorescence intensity can be clearly known through the color difference, and the concentration of 0.25 % is selected for doping to achieve the balance between the emission intensity and the color of the fluorescent substance. We use hot‐pressing to finish the fluorescent polyurethane (FPU) film on the surface of the fabric at a lower temperature (Compared with high temperature and high pressure dyeing method). There is a potential application prospects for our fluorescent polyurethane films in chemical sensing, biological imaging, anti‐counterfeiting technology, and smart light‐emitting fabrics.