Capturing Doublet Intermediate Emitters by Chemically Crosslinking Confinement towards Spatiotemporal Encryption.

Photoluminescence is one of the most meticulous ways to manipulate light energy. Typical photoluminescent emitters are mostly stable substances with a pure photophysical process of spontaneous photon-emission from their excited states. Intermediate emitters are elusive attributing to their synchronous energy transfer process including photophysical and incomplete photochemical pathways. An intermediate emitter containing radicals is more difficult to be observed due to its inherent chemical reactivity. Here, these challenges are overcome by spontaneously formed space limitations in polymer crosslinking networks meanwhile chemically active intermediates are captured. These doublet intermediates exhibit unique long-wavelength emissions under chemically crosslinking confinement conditions, and their luminous mechanism provides a novel perspective for designing intermediate emitters with liquid-crystal character and photoresponsive features towards spatiotemporal encryption, promising for the detection of photochemical reactions and the development of fascinating luminescent systems.

A Light-Activated Polymer Composite Enables On-Demand Photocontrolled Motion: Transportation at the Liquid/Air Interface.

Swimmers at liquid/air interfaces have drawn enormous attention because of their potential applications. Described herein is one novel light-driven swimmer based on a bimorph composite structure of a photoresponsive liquid-crystalline polymer network and a commercially available polyimide (Kapton). The motion of the swimmer can be controlled by photoirradiation. The bilayer-structured film shows quickly photoinduced bending towards the Kapton side upon exposure to UV light, and recovers immediately after removal of light. When placed on a liquid surface, the swimmer propels itself continually though rhythmic beating the liquid like a dolphin moving forward with its tail fin. Besides, light-powered rotation of the swimmer is successfully achieved by simply changing the length-width ratio and the irradiation site, mimicking the function of a dolphin's pectoral fin. Combining the forward movement and rotation motion together, on-demand directional control of the photo-driven swimmer can be readily obtained at room temperature, showing promise for miniaturized units for transportation.

Hierarchical Self-Assembly in Liquid-Crystalline Block Copolymers Enabled by Chirality Transfer.

Helical topological structures are often found in chiral biological systems, but seldom in synthesized polymers. Now, controllable microphase separation of amphiphilic liquid-crystalline block copolymers (LCBCs) consisting of hydrophilic poly(ethylene oxide) and hydrophobic azobenzene-containing poly(methylacrylate) is combined with chirality transfer to fabricate helical nanostructures by doping with chiral additives (enantiopure tartaric acid). Through hydrogen-bonding interactions, chirality is transferred from the dopant to the aggregation, which directs the hierarchical self-assembly in the composite system. Upon optimized annealing condition, helical structures in film are fabricated by the induced aggregation chirality. The photoresponsive azobenzene mesogens in the LCBC assist photoregulation of the self-assembled helical morphologies. This allows the construction and non-contact manipulation of complicated nanostructures.