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Using polymerizable cholesteric liquid crystal (CLC) paints, we prepare circularly polarized freestanding films that enable students to acquire a basic understanding of circular polarization and molecular chirality. The polymerized helical structures of CLC films can exhibit brilliant structural colors by selective reflection of visible light corresponding to their helical pitch. For the fabrication of freestanding and circularly polarizing films of various colors and shapes, students control helical pitch with the amount of chiral dopants and stabilize them by photopolymerization. On the basis of an understanding of the circularly polarized reflection of CLC paints, students can encode secret letters that are visible only with a specific circular polarizer.

Viologen‐based reactive mesogen (VRM) is newly designed and synthesized for the development of polarization‐dependent, color‐tunable, and transparent electrochromic (EC) smart windows. By controlling electric field, the color of VRM can be intentionally tuned due to the formation of dication (D state), cation‐radical (C state), and neutral state (N state). Based on the deep understanding of phase transition of VRM, a uniaxially oriented VRM hierarchical nanostructure is successfully constructed on the macroscopic area by simple coating and self‐assembly processes. The subsequent photopolymerization significantly improves thermal, mechanical, and chemical stabilities of the VRM thin film. In addition to the control of color, the transmittance of uniaxially oriented VRM‐based EC smart window can be precisely tuned by rotating a linear polarizer. [ABSTRACT FROM AUTHOR]

Exploiting the ability to directly deposit larger‐sized, flexible, alloying‐type sodium‐ion battery electrodes without the need of additional inactive components and processing steps is a strategic way to achieve higher gravimetric capacities which will be suitable for commercial‐level sodium‐ion (SIB) pouch cell manufacturing. In this regard, a simple, template‐free electroplating protocol is reported for designing phase‐pure tin antimonide (TA)‐based negatrode. An optimum control over the potentiostatic electroplating parameters allows the preferential formation of dendritic nanostructures over an electroplated foam‐based current collector. The prepared negatrode and Mn‐based Prussian blue analog positrode in full coin cell format deliver an average nominal working voltage of 3.0 V with a discharge energy density of 342 Wh kg−1. In single‐layer full pouch cell format, an 8.01 mAh capacity (89.89 mAh g−1, 593.3 µAh cm−2) is achieved at an undeformed state and 97.12% capacity is retained at 180° bend condition. In multi‐layer full pouch cell format, a 35.86 mAh capacity (80.58 mAh g−1, 531.2 µAh cm−2) is achieved with 62.77% capacity retention after 200 cycles (0.125 C). The results of this work showcase how a simple, template free, aqueous electrolyte based electroplating protocol can be developed for the direct fabrication of large‐sized, flexible, alloying‐type negatrodes for commercial SIB pouch cells. [ABSTRACT FROM AUTHOR]

To develop smart ionic skins capable of multi‐responsiveness and switchable ionic conductivity, a stimuli‐responsive and ionic conductive azobenzene‐based monomer is newly synthesized, uniaxially oriented, and polymerized for anisotropic liquid crystal elastomers (LCEs). Since the uniaxially oriented monodomain LCE with ionic asymmetric azobenzene monomers (i‐AAM) is prepared by thermal oligomerization, uniaxial stretching, and subsequent photopolymerization, the stimuli‐responsive i‐AAM LCE is thermally contracted by increasing the temperature above TNI as well as is bent along the aligned direction by irradiating it with UV light. In addition to the change of shape, the ionic conductivity of the LCE is reversible in response to heat and light stimuli. Polydomain i‐AAM LCE polymerized without the stretching process exhibits higher ionic conductivity than stretched monodomain LCE due to the initially formed stable ionic pathways. Ionic conductivity can also be switched simultaneously by polarity changes in response to the photoisomerization of i‐AAM, increased mobility from heat, and an elastic mechanoresponse from external stresses. These i‐AAM LCE‐based soft grippers exhibit stimuli‐responsive grasping and releasing actuation and detect ionic conductivity switches finely, suggesting potential as smart skins for advanced soft robots. [ABSTRACT FROM AUTHOR]