Exploring the Circular Polarization Capacity from Chiral Cellulose Nanocrystal Films for a Photo‐Controlled Chiral Helix of Supramolecular Polymers

Abstract

Circularly polarized light (CPL) is key to asymmetric photochemistry as it could impart the chiral organization information into chemical products. Here, we demonstrate the circular polarization capacity of chiral cellulose nanocrystal (CNC) films to trigger photo‐alignment of achiral supramolecular polymers into helical structures. Right‐handed transmitted (T‐) CPL was generated from self‐assembled CNC films, which induced amorphous azobenzene (Azo) supramolecular polymers into chiral structures. The chiral induction effect of T‐CPL is enhanced on Azo polymers with longer spacers. The absorptive dissymmetry factor (gabs) values of liquid‐crystal supramolecular polymers can be amplified significantly (over 10 times) after T‐CPL irradiation. Moreover, by integrating carbon dots into CNC films, CPL emission with a considerable luminescence dissymmetry factor (glum) up to −0.66 was achieved, and it could be used for the photo‐alignment of Azo polymers with high chiroptical properties. This work provides new insight for the photo modulation of supramolecular polymers by CPL‐active materials.

Chiral supramolecular nanomaterials: From chirality transfer and amplification to regulation and applications

“…Reproduced with permission. [36] Copyright 2022, with permission from Wiley-VCH. AC, 2-anthracenecarboxylic acid; BTAM, benzene-1,3,5-tricarboxamide motif with an aminopyridine group; CD, circular dichroism; CPL, circularly polarized luminescence; DMSO, dimethyl sulfoxide; ET, Förster resonance energy transfer; SAv, streptavidin; TPEs, tetraphenylethylenes.…”

“…[50][51][52][53][54][55][56][57] Xu et al investigated the emission of T-CPL and CPL with elevated g values from chiral CNC films to induce the helical arrangement of supramolecular polymers. [36] Figure 3F illustrates the transformation of amorphous Azo polymers with varying spatial lengths from a state of disorder to chiral structures through T-CPL induction. The research they conducted offered new perspective on the asymmetric photochemistry initiated by CPL in materials derived from biological sources and inspired by biology.…”

Air‐tolerant upconverted circularly polarized luminescence enabled by confined space of chiral micelle

“…In previous work, tripletenergy transfer and annihilation-based photon upconversion have been demonstrated as a general and effective strategy to amplify the circular polarization of luminescent annihilators. [34][35][36][37][38] Photon upconversion can convert low-energy photons into high-energy photons. In organic systems, it can be classified into three categories according to the different mechanisms: two-or multi-photon absorption, hot-band-absorption-based upconversion, and triplettriplet annihilation upconversion (TTA-UC).…”