Waterborne Polyurethanes with Tunable Fluorescence and Room-Temperature Phosphorescence

Abstract

Single-component materials with both fluorescence and room-temperature phosphorescence (RTP) are useful for ratiometric sensing and imaging applications. On the basis of a general design principle, an amino-substituted benzophenone is covalently incorporated into waterborne polyurethanes (WPU) and results in fluorescence and RTP single-component dual-emissive materials (SDMs). At different aminobenzophenone concentrations, the statistical, thermal, and optical properties of these SDMs are characterized. Despite their similar thermal behaviors, the luminescence properties as a function of the chromophore concentration are quite different: increasing concentrations led to progressively narrowed singlet-triplet energy gaps. The tunability of fluorescence and RTP via chromophore concentration is explained by a previously proposed model, polymerization-enhanced intersystem crossing (PEX). The proposal of PEX is based on Kasha's molecular exciton theory with a specific application in polymeric systems, where the polymerization of luminophores results in excitonic coupling and enhanced forward and reverse intersystem crossing. The mechanism of PEX is also examined by theoretical calculations for the WPU system. It is found that the presence of K1 aggregates indeed enhances the crossover from singlet excited states to triplet ones.

Effect of hydroxyl‐terminated poly(fluoroalkyl methacrylate) main‐chain length on the microphase separation of waterborne fluorinated polyurethane

“…All the samples presented three characteristic thermal transitions. The plateau at around −50 °C corresponded to the glass transition temperature of the soft segments ( T g,s ); the other plateau at about −12 °C was ascribed to the glass transition temperature of the shortest hard segments ( T g,h ); the broad melting peak in the range 50–100 °C belonged to the short‐range order in hard segments ( T m,h ) . The enthalpy (Δ H ) of the short‐range order in hard segments was determined by the integration of the peak areas.…”

Research on Long-Lived Room-Temperature Phosphorescence of Carbazole-Naphthalimide Polylactides

“…For phosphorescent polymer materials, ring-opening polymerization, free radical binary co-polymerization, and covalent cross-linking reactions are considered to be a reasonable chemical strategy to achieve phosphorescent polymer materials. Zhou et al [19] incorporated a benzophenone derivative with a donor-acceptor structure into an aqueous polyurethane, and the aqueous polyurethane material will exhibit room-temperature phosphorescence. Fraser and Zhang et al [20] designed a series of dual-emissive polymers with both fluorescence and RTP based on difluoroborn dibenzoylmethane derivatives.…”

Modulation of Thermally Activated Delayed Fluorescence in Waterborne Polyurethanes via Charge‐Transfer Effect

“…In order to restrain thermal quenching of triplet excitons, luminogens have to be prepared as crystals or incorporated in polymers . Waterborne polyurethane (WPU) is a kind of polymer with tunable soft and hard segments, which has a satisfactory film‐forming property and has been widely used as coatings, leathers, textiles, and matrices for functional materials . Compared to terminal‐functional polymers, like polylactides (PLAs), luminogens covalently incorporated in WPU main chain via polyaddition reaction suffer less aggregation of luminogens in that luminogens in the main chains have smaller free volumes.…”

“…[36][37][38][39][40][41][42] Waterbornep olyurethane (WPU) is ak ind of polymer with tunable soft and hard segments, which has as atisfactory film-formingp roperty and has been widelyu sed as coatings, [43] leathers, [44] textiles, [45] and matrices for functional materials. [46][47][48] Compared to terminal-functional polymers, like polylactides( PLAs), luminogens covalently incorporated in WPU main chain via polyadditionr eactions uffer less aggregation of luminogens in that luminogens in the main chains have smallerf ree volumes. Besides, the rigidity of WPU films can be easily tuned without decreasing molecular weights by changing the ratio of soft andh ard segments to suppress thermal quenching.…”