Stimuli‐Responsive Electrospun Fluorescent Fibers Augmented with Aggregation‐Induced Emission (AIE) for Smart Applications

Abstract

This review addresses the latest advancements in the integration of aggregation-induced emission (AIE) materials with polymer electrospinning, to accomplish fine-scale electrospun fibers with tunable photophysical and photochemical properties. Micro-and nanoscale fibers augmented with AIE dyes (termed AIEgens) are bespoke composite systems that can overcome the limitation posed by aggregation-caused quenching, a critical deficiency of conventional luminescent materials. This review comprises three parts. First, the reader is exposed to the basic concepts of AIE and the fundamental mechanisms underpinning the restriction of intermolecular motions. This is followed by an introduction to electrospinning techniques pertinent to AIE-based fibers, and the core parameters for controlling fiber architecture and resultant properties. Second, exemplars are drawn from latest research to demonstrate how electrospun nanofibers and porous films incorporating modified AIEgens (especially tetraphenylethylene and triphenylamine derivatives) can yield enhanced photostability, photothermal properties, photoefficiency (quantum yield), and improved device sensitivity. Advanced applications are drawn from several promising sectors, encompassing optoelectronics, drug delivery and biology, chemosensors and mechanochromic sensors, and innovative photothermal devices, among others. Finally, the outstanding challenges together with potential opportunities in the nascent field of electrospun AIE-active fibers are presented, for stimulating frontier research and explorations in this exciting field.

Size Recognition of External Molecules on Polymer Brushes Using Aggregation-Induced Emission

“…In 2001, Tang et al pioneered a class of aggregation-induced emission (AIE)-type luminogens (i.e., AIEgens) that exhibited enhanced emission in the aggregated states, which is a phenomenon opposite to ACQ. − Restriction of the molecular motions in the aggregated state suppresses thermal decay of the excited luminogens, resulting in enhanced photo-emission. AIEgens have also been incorporated in polymers, finding applications in microporous materials and biological applications. ,− The embedding of AIEgens into polymer brushes has also offered control in optoelectronic properties and sensing applications. , …”

Photo-Controlled Nano-Supramolecular Size and Reversible Luminescent Behaviors Based on Cucurbit[7]uril Cascaded Assembly

“…Up to date, several stimuli-responsive AIE materials have been fabricated. 15,16 Light, as a powerful non-touch stimulus with no waste generation, high accuracy, and remotely controlled characteristic, is an ideal candidate among the various external stimuli. 17 Various categories have been employed for realizing AIEfeatured photoactivatable fluorophores including (i) reversible photochromic reactions, 21 (ii) irreversible photochemical reactions, 22 (iii) reactive oxygen species-mediated photoactivation, 23 and (iv) light-induced crystallization.…”

Monomer Emission Mechanism Research of Tetraphenylethene Derivative with Supramolecular Self-Assembly in Polymer Microspheres

“…24 In addition, the supramolecular self-assembly structure of TPE derivatives can restrict intramolecular rotation by the binding effect of polymer chains. 25 There are possibilities to tune the molecular aggregate or self-assembly by expanding polymer chains. 26 This novel work is of instructive significance in the studies for the luminescence mechanism of other AIEgens.…”

“…Simple TPE derivatives with weak supramolecular self-assembly may not form aggregates through few non-covalent interactions (hydrogen bonding, π–π interaction, and van der Waals forces) . In addition, the supramolecular self-assembly structure of TPE derivatives can restrict intramolecular rotation by the binding effect of polymer chains . There are possibilities to tune the molecular aggregate or self-assembly by expanding polymer chains .…”