Helix-Sense Selective Polymerization versus Polymerization-Induced Helix-Sense Selective Self-Assembly: From Controlled Synthesis to in Situ Chiral Self-Assembly

ConspectusInspired by the precise helical architectures of biomacromolecules, researchers are increasingly focusing on the synthesis of helical polymers and supramolecular assemblies. Helix-sense selective polymerization has emerged as a reliable method for preparing optically active helical polymers, where a preferred screw-sense can be induced by chiral initiators or monomers and maintained through steric hindrance and supramolecular interactions. However, the preparation of the corresponding chiral polymer assemblies requires prior synthesis followed by self-assembly, a process that is typically inefficient and offers limited ability to control pathway complexity under equilibrium or nonequilibrium conditions. Therefore, developing novel strategies for the facile preparation of chiral polymer assemblies with a predictable morphology, controlled molecular parameters, and tunable chiroptical expression is of significant importance.Achieving simultaneous control over the in situ self-assembly and the noncovalent chiral ordering within the resulting nanostructures remains a significant challenge. To address this, a strategy termed polymerization-induced chiral self-assembly (PICSA), and more specifically polymerization-induced helix-sense selective self-assembly (PIHSSA), has been reported by our group. This method combines living polymerization with supramolecular stacking to achieve an in situ helical preferred arrangement of building units during polymer chain growth, directly yielding chiral nanoassemblies with tunable morphologies and high solid contents. Various living/controllable polymerization mechanisms, including reversible addition-fragmentation chain-transfer polymerization, ring-opening polymerization, and metal-catalyzed coordination polymerization, can be applied to PIHSSA. This facilitates the systematic study of hierarchical chirality transfer, nonlinear asymmetric amplification effects such as the sergeant-and-soldier principle, and the pathway complexity that dictates the formation of supramolecular architectures.This Account provides a comprehensive overview of our recent endeavors to explore the in situ synthesis and regulation of chiral polymer assemblies. We compare the principles and advances between traditional helix-sense selective polymerization (HSSP) and emerging PIHSSA, focusing on how the latter enables the in situ construction of chiral superstructures with customizable morphologies, dynamic helicity switching, and enhanced chiroptical response. We further discuss key parameters determining chiroptical activity and assembly pathways, including the degree of polymerization, polymerization temperatures, solvents, and solvophilic segments. We highlight the potential of PIHSSA as a universal platform for designing next-generation chiral polymer assemblies while also pointing out the remaining challenges in expanding monomer diversity, realizing complex nanostructures, and translating these systems into practical applications.