Vapochromic polyketone films based on aggregation‐induced enhanced emission

Abstract

Aliphatic polyketone (PK) films physically mixed with moderate amounts (0.6 wt%) of 4,4′‐bis(2‐benzoxazolyl)stilbene (BBS) fluorophores were demonstrated to be sensitive to volatile organic compounds. Notably, BBS/PK blends were prepared by means of a continuous 1‐step extrusion process in a pilot‐scale twin screw extruder and compression molded followed by rapid quenching in liquid nitrogen to get thin films (thickness of 150 μm) containing molecularly dispersed blue emissive BBS fluorophores. The 0.6 wt% BBS/PK films demonstrated significant vapochromism when exposed to volatile organic compounds characterized by favorable interactions with the polymer matrix such as chloroform. Solvent absorption caused PK matrix plasticization, thus increasing BBS mobility and triggering the self‐associations of molecules into bluish green‐emissive excimers/aggregates thanks to the emersion of the typical band at 500 nm. This phenomenon preferentially involves the BBS/PK film layers close to the air‐contact surface without affecting the bulk characteristics of the PK matrix. The easy modulation of the luminescent properties of PK films by varying the supramolecular organization of BBS dispersed molecules by chemical perturbations, and the use of melt‐processing procedures suggests the use for the first time of aliphatic PK in the development of smart materials for sensing applications.

Recent advances in aggregation-induced emission (AIE)-based chemosensors for the detection of organic small molecules

“…The casted thin film of C18 revealed bright blue fluorescence because of AIEE. 242 Interestingly, the exposure to chloroform, acetone, and methanol led to a blue-to-green fluorescence colour change, attributable to solvent absorption, leading to the self-association of C18 molecules within the matrix. On the other hand, Zhang and Yu et al developed a VOC sensor based on polymer composites ( C19 ) containing polysulfone matrices and TPE additives, both of which functionalized with matching functional side-groups.…”

Organic compounds for solid state luminescence enhancement/aggregation induced emission: a theoretical perspective

“…[29][30][31] The presence of many solid-state molecular arrangements introduces another variable that may further modulate the emissive behavior and that sometimes results in different aggregated morphologies of the same compound displaying different photoluminescence. [32][33][34][35] The renewed boost to the study of materials showing AIE, also known as AIEgens, has resulted in the development of a conspicuous number of experimental applications concerning novel sensing and imaging techniques [36][37][38][39][40][41][42][43][44] but also other crucial technologies like organic light emitting diodes (OLEDs) or luminescent solar concentrators (LSCs). [45][46][47][48] The experimental community has been rapidly followed by the theoretical one, that has found in the AIE phenomenon a fertile playground as it includes a number of physical processes whose interpretation is highly relevant also for the advancement of theoretical approaches.…”

“…The renewed boost to the study of materials showing AIE, also known as AIEgens, has resulted in the development of a conspicuous number of experimental applications concerning novel sensing and imaging techniques 36–44 but also other crucial technologies like organic light emitting diodes (OLEDs) or luminescent solar concentrators (LSCs). 45–48 The experimental community has been rapidly followed by the theoretical one, that has found in the AIE phenomenon a fertile playground as it includes a number of physical processes whose interpretation is highly relevant also for the advancement of theoretical approaches.…”