Self-recovery of chiral microphase separation in an achiral diblock copolymer system

Molecular Imprinting Strategy Enables Circularly Polarized Luminescence Enhancement of Recyclable Chiral Polymer Films

Circularly polarized luminescence (CPL) plays a crucial role in the fields of optical display and information technology. The pursuit of high dissymmetry factors (glum) and fluorescence quantum yields in CPL materials remains challenging due to inherent trade-offs. In this work, molecular imprinting technology is employed to develop novel CPL-active polymer films based entirely on achiral fluorene-based polymers, achieving an enhanced glum value exceeding 4.2 × 10-2 alongside high quantum yields. These chiral molecularly imprinted polymer films (MIPF) are synthesized via a systematic three-step process: co-assembly with limonene and a porphyrin derivative (TBPP), interchain crosslinking, and subsequent removal of small molecules. During this process, limonene acts as the chiral inducer, while TBPP serves dual roles as both the chiral enhancer and imprinted molecule. The elimination of TBPP creates chiral sites for various fluorescent molecules, facilitating full-color CPL emission. The chiral MIPF exhibits stable CPL performance even after multiple cycles of post-assembly and removal. Furthermore, these films can function as interfacial microreactors, enabling in situ chemical reactions that dynamically regulate CPL signals. Additionally, chiral self-organization within achiral azobenzene polymer films can also be achieved using MIPF, serving as intense chiral light sources.

Precise AIE-Based Ternary Co-Assembly for Saccharide Recognition and Classification

Saccharides are involved in nearly all life processes. However, due to the complexity and diversity of saccharide structures, their selective recognition is one of the most challenging tasks. Distinct from conventional receptor designs that rely on delicate and complicated molecular structures, here a novel and precise ternary co-assembled strategy is reported for achieving saccharide recognition, which originates from a halogen ions-driven aggregation-induced emission module called p-Toluidine, N, N'-1-propen-1-yl-3-ylidene hydrochloride (PN-Tol). It exhibits ultra-strong self-assembly capability and specifically binds to 4-mercaptophenylboronic acid (MPBA), forming highly ordered co-assemblies. Subsequent binding of various saccharides results in heterogeneous ternary assembly behaviors, generating cluster-like, spherical, and rod-like microstructures with well-defined crystalline patterns, accompanied by significant enhancement of fluorescence. Owing to the excellent expandability of the PN module, an array sensor is constructed that enables easy classification of diverse saccharides, including epimer and optical isomers. This strategy demonstrates wide applicability and paves a new avenue for saccharide recognition, analysis, and sequencing.

Simultaneous Chiral Fixation and Chiral Regulation Endowed by Dynamic Covalent Bonds

The construction of chiral superstructures through the self-assembly of non-chiral polymers usually relies on the interplay of multiple non-covalent bonds, which is significantly limited by the memory ability of induced chirality. Although the introduction of covalent crosslinking can undoubtedly enhance the stability of chiral superstructures, the concurrent strong constraining effect hinders the application of chirality-smart materials. To address this issue, we have made a first attempt at the reversible fixation of supramolecular chirality by introducing dynamic covalent crosslinking into the chiral self-assembly of side-chain polymers. After chiral induction, the reversible [2+2] cycloaddition reaction of the cinnamate group in the polymer chains can be further controlled by light to manipulate inter-chain crosslinking and decrosslinking. Based on this photo-programmable and dynamic chiral fixation strategy, a novel pattern-embedded storage mechanism of chiral polymeric materials was established for the first time.

A Subtle Change in the Flexible Achiral Spacer Does Matter in Supramolecular Chirality: Two-Fold Odd-Even Effect in Polymer Assemblies

Precise control over the chirality and morphologies of polymer assemblies, a remaining challenge for both chemists and materials scientists, is receiving ever-increasing attention in the recent years. Herein, we report the subtle manipulation of the achiral spacers from the chiral stereocenter to the azobenzene (Azo) unit, of which the chiroptical consistency or chiroptical inversion of self-assemblies could be successfully controlled and present "two-fold" odd-even effect. Furthermore, morphological transitions from 0D spherical micelles, 1D worms, and nanowires to 3D vesicles, spindle- and dumbbell-shaped vesicles were also unexpectedly found to exhibit odd-even correlations. These observations were collectively elucidated by mesomorphic properties, stacking modes, chiroptical dynamics, and stimuli-responsive behaviors. Negligible modifications to the spacer structures can enable remarkable modulation of supramolecular chirality and anisotropic topologies in polymer assemblies, which is of great significance for the design of complex chiral functional polymers.

Conformationally supramolecular chirality prevails over configurational point chirality in side-chain liquid crystalline polymers

In nature, the communication of primary amino acids in the polypeptides influences molecular-level packing, supramolecular chirality, and the resulting protein structures. In chiral side-chain liquid crystalline polymers (SCLCPs), however, the hierarchical chiral communication between supramolecular mesogens is still determined by the parent chiral source due to the intermolecular interactions. Herein, we present a novel strategy to enable the tunable chiral-to-chiral communication in azobenzene (Azo) SCLCPs, in which the chiroptical properties are not dominated by the configurational point chirality but by the conformationally supramolecular chirality that emerged. The communication of dyads biases supramolecular chirality with multiple packing preference, thereby overruling the configurational chirality of the stereocenter. The chiral communication mechanism between the side-chain mesogens is revealed through the systematic study of the chiral arrangement at the molecular level, including mesomorphic properties, stacking modes, chiroptical dynamics and further morphological dimensions.