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This work introduces a visual chirality-sensing system based on a helicity-memory poly(diphenylacetylene). Upon reacting with different enantiomers of chiral amines, the polymer exhibits striking color and fluorescence changes driven by helix-pitch transitions between stretched cis-transoidal and contracted cis-cisoidal states. These shifts arise from the on/off formation of intramolecular amide hydrogen-bonding networks, functioning like a “helical spring” that amplifies subtle chiral differences. The system enables naked-eye enantiomer discrimination and highly accurate ee determination, detecting variations as small as 0.5% in the challenging 98–100% ee range. Quantification is further achievable via simple RGB analysis, highlighting its potential for rapid, on-site chiral analysis relevant to pharmaceuticals and fine chemicals.

This study reveals a unique dual memory effect in a poly(biphenylylacetylene) (PBPA), where both the macromolecular helicity and axial chirality of the pendants can be induced by non-racemic alcohols and retained after removing the chiral source. Remarkably, the helical sense can be reversibly switched in the solid state simply by alternating treatments with (R)- and (S)-alcohols. Exploiting this property, we developed the first switchable chiral stationary phase (CSP) for HPLC, capable of reversing the elution order of enantiomers using the same column. This work demonstrates the potential of helicity-memory polymers for intelligent chiral materials, enantioseparation, and advanced separation technologies.

This study demonstrates that a polymer’s induced helicity can be stably “memorized” after the chiral inducer is removed, as long as suitable achiral small molecules are present. Using poly(4-carboxyphenylacetylene), we show that a one-handed helix induced by chiral amines remains intact after full replacement with achiral amines, retaining strong induced CD signals. The helical memory can self-repair and remains stable for months at room temperature, with an estimated half-life of over four years. The retention efficiency is highly sensitive to the structure of the achiral molecules, highlighting the importance of hydrogen bonding and acid–base interactions. This work introduces the concept of achiral molecular chaperones that stabilize macromolecular helicity.

This work introduces a helix-sense-selective memory polymerization (HSMP) that enables the rapid, one-pot synthesis of helicity-memorized poly(biphenylylacetylene)s (PBPAs) in water from achiral monomers. Driven by chiral ionic acid–base interactions, the polymerization proceeds under kinetic control to produce one-handed helical polymers that instantly “memorize” their helicity—hundreds of times faster than conventional two-step induction methods. The resulting PBPAs form lyotropic cholesteric liquid crystals, which can co-assemble with various achiral dyes to generate color-tunable circularly polarized luminescence (CPL). This HSMP strategy provides a powerful route for rapid synthesis of helical polymers and advanced photonic materials.

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