Multicolor Luminescence of a Polyurethane Derivative Driven by Heat/Light-Induced Aggregation

Abstract

The study of aggregate formation and its controllable effect on luminescence behavior has a far-reaching influence in establishing a universal aggregation photophysical mechanism. In this paper, we obtained clusters with different extents of aggregation by heat-induced or light-triggered aggregation of a new polyurethane derivative (PUE). The controllable regulation of multicolor fluorescence of a single (nondoped) polymeric material is realized. The luminescence behavior of PUE varies with microscopic control of the aggregation structure. Compared with the powder state, the enhanced atom–atom and group–group interactions of PUE-gel effectively limit the nonradiative transitions in the excited state and result in a red-shift in emission. This work avoids complex organic synthesis and demonstrates a simple strategy to induce aggregation and regulate the emitting color of macromolecules, providing a template for developing new materials for multicolor fluorescence. In addition, a pattern was constructed with encryption, anticounterfeiting, and information transmission functions which provide a proof-of-concept demonstration of the practical potential of PUE as a smart material.

Recent Progress in Nonconventional Luminescent Macromolecules and their Applications

“…The many noncovalent interaction sites on the polyurethane chain were conducive to the aggregation-induced polychromatic blue-to-red fluorescence. 71 2.3. Exploration of Full-Color Emission.…”

“…Heating samples at 80 °C for a few hours and then at 120 °C achieved a fluorescence transition faster than by heating only at 120 °C, implying that the aggregation process requires time to occur. The many noncovalent interaction sites on the polyurethane chain were conducive to the aggregation-induced polychromatic blue-to-red fluorescence …”

“…More advanced and accurate computational methods are needed to support the interaction analysis of NCLMs in excited states. Gaussian or dynamics simulation software have been mainly used to optimize the molecular structure of NCLMs, analyze their conformation, calculate their electronic structure and electron density distribution, ground state/excited state energy levels, spin–orbit coupling constants, highest occupied and lowest unoccupied molecular orbital (HOMO and LUMO) contours, and the inter/intrachain short interatomic contacts. ,,, Also, the unconventional luminescence of small molecules has inspired and served to help the analysis of interactions in NCLMs . For example, Tang et al obtained a new type of cyclodextrins through modification of amino acids.…”