Responsive photonic crystals (RPCs) assembled by monodisperse colloidal particles have attracted enormous interest recently due to their tremendous applications in smart devices. Their structural colors can be determined by particle sizes. However, the lack of a reliable way to tune the sizes in situ limits their development. Herein, we present an efficient route to solve this problem through the fabrication of spherical polymeric particles with light-triggered reversible swelling behavior via surfactant-free reversible additionfragmentation chain transfer (RAFT) emulsion polymerization-induced self-assembly (PISA). Amphiphilic macro-RAFT agents containing azobenzene groups were synthesized and subsequently employed to mediate the polymerization of methyl methacrylate. Uniform submicron spheres were obtained by modulating solid contents and other parameters. Benefiting from the photoisomerization of azobenzene moieties, the particle sizes expanded and contracted upon alternative ultraviolet/visible-light irradiation accordingly. This strategy will be a supplement to the emulsion PISA and especially give aid to the progress of the RPC materials.

Anisotropic polymeric nanoparticles (NPs) have attracted considerable attention due to their morphology-dependent applications in the fields of nanocatalysts, drug delivery and sensors. By introducing liquid crystalline (LC) driving force into NPs, the region of non-spherical shapes in phase diagrams can be broadened effectively, which attracts great interest of many researchers. LC mesogens can be easily introduced to monomers, such as acrylates and methacrylates, as side groups connected by spacers with tunable length, and then side-chain LC polymers can be acquired after polymerization accordingly. Among these polymers, amphiphilic block copolymers (BCPs) have been widely studied, attributed to their property of spontaneous assembly into NPs under appropriate conditions. In this review, based on traditional solution self-assembly and polymerization-induced self-assembly, the recent research into side-chain LC BCP NPs is elaborated in terms of the aspects of the types of LC mesogens, LC phases, morphologies and functionalities. Finally, we summarize recent progress, and prospect the development trend in the future.

Polymerization‐induced self‐assembly incorporating liquid crystallization, as a polymerization‐induced hierarchical self‐assembly (PIHSA) method to produce polymeric particles with anisotropic morphologies facilely and efficiently, has drawn wide attention recently. However, the means of regulating the morphologies of liquid crystalline (LC) polymer assemblies still need to be explored. Herein, we present a route to fabricate the twisted ribbons via PIHSA containing azobenzene based on poor reversible addition‐fragmentation chain transfer (RAFT) control, called as poorly controlled PIHSA. Cyano‐4‐(dodecylsulfanylthiocarbonyl)sulfanyl pentanoic acid‐2‐(2‐pyridyldithio) ethyl ester was used as the RAFT agent with poor controllability, and the morphological evolution from ribbons to twisted ribbons could be observed in the corresponding PIHSA system. The formation mechanism of the twisted ribbons was studied systematically and the broad molecular weight distribution was considered to be the decisive factor. Moreover, the supramolecular chirality induced by symmetry breaking was also related to the twist of the ribbons. This study enriches the methods of controlling the morphologies of LC polymer particles and is helpful for further clarifying the mechanism of PIHSA.This article is protected by copyright. All rights reserved

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