AIE-Active, Stimuli-Responsive Fluorescent 2D Block Copolymer Nanoplatelets Based on Corona Chain Compression

Abstract

Aggregation-induced emission (AIE) represents a powerful tool in nanoscience as a result of enhanced luminescence in the condensed state. Although AIEgenic materials have been utilized in a wide range of applications, well-defined self-assembled nanoparticles with tailorable and uniform dimensions and morphology remain challenging to access. Herein, we use the seeded growth, living crystallization-driven self-assembly (CDSA) method to prepare size-tunable and uniform AIE-active 2D nanoplatelets from amphiphilic block copolymer (BCP) precursors with a crystallizable core-forming block and a corona-forming block to which tetraphenylethene (TPE) groups were covalently grafted as AIE-active pendants. The nanoplatelets were formed as a result of a solvophobicity-induced 1D to 2D morphology preference change, which accompanied the seeded growth of a BCP with a quaternized corona-forming block bearing the TPE luminogen. The 2D nanoplatelets exhibited a solvent-responsive fluorescent emission, and examples with coronas containing homogeneously distributed AIE-active TPE groups and Hg­(II)-capturing thymine units exhibited excellent performance as proof-of-concept “turn-on” sensors for Hg­(II) detection with a rapid response, high selectivity, and a low detection limit (5–125 × 10–9 M, i.e., 1–25 ppb). The fluorescence intensity was found to be nonlinear with respect to analyte concentration and to increase with the area of the nanoplatelet. This behavior is consistent with a cooperative mechanism based on changes in the steric compression of the corona chains, which gives rise to a restriction of the intramolecular motion (RIM) effect.

Aggregation-induced emission-active micelles: synthesis, characterization, and applications

“…18g) were covalently grafted to the copolymer as AIE-active components. 153 The 2D nanoplatelets with uniformly distributed AIE-active TPE moieties and Hg( ii )-capturing thymine units displayed solvent-responsive fluorescent emission effects. This probe demonstrated remarkable performance for the detection of Hg( ii ) with a quick response, excellent selectivity, and detection limit as low as 1–25 ppb.…”

Noncancerous disease-targeting AIEgens

“…24 Recently, AIEgens have also been proven to be developed with a particular shape. 25 Until now, a variety of AIEgens have been synthesized and applied for the detection, diagnosis, bioimaging, and bioimaging-guided therapy of noncancerous diseases upon rational designs and functionalized strategies. [26][27][28] However, although several studies and reviews have focused on the AIEgen-based intelligent detection, imaging, or therapy of cancer, 26,[29][30][31][32] a broad review of their value in noncancerous diseases has so far been lacking.…”

Bioinspired crowding directs supramolecular polymerisation

“…Our results highlight that crowding effects direct the outcome of supramolecular self-assembly, enabling accessibility to more diverse morphologies without the need to change external parameters, such as solvent or temperature 24,25 . We anticipate that relevant functional properties gated behind specific (hierarchical) supramolecular morphologies will become accessible based on supramolecular crowding approaches [26][27][28][29][30] , which should accelerate the development of smart materials based on functional supramolecular polymers [31][32][33][34][35] .…”