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Polarization hits a bull's-eye Polymer-based ferroelectric materials are attractive because they can be solution processed cheaply and have much greater flexibility than ceramics. Guo et al. found concentric circular bands of polarization in a ferroelectric polymer that look like a bull's-eye target (see the Perspective by Martin). This self-organized toroidal texture is aligned perpendicularly to the axis of the polymer chains, allowing the authors to demonstrate selective absorption of infrared radiation and manipulation of terahertz radiation. This distinct structure in a polymer could be of interest for exploring and using other exotic effects. Science , this issue p. 1050 ; see also p. 992

The miniaturization of electronic devices and power systems for capacitive energy storage under harsh environments requires scalable high-quality ultrathin high-temperature dielectric films. To meet the need, ultrasonic spray-coating (USC) can be used. Novel polyimides with a dipolar group, CF

Flexible strain sensors are critical to several potential intelligent applications, such as human-machine interfaces, soft robotics, human motion detection, and safety monitoring of components. Stretchable functional materials are important components of strain sensors, and they are still major challenges for high performance strain sensors. Herein, we demonstrate a novel strategy of designing and optimizing flexible strain sensor by developing topological structure modulated high permittivity elastic nanocomposite. The topological structure with three-phase percolative nano-nanonetworks produces synergistic effects of space charge enhancement and local electric field modulation, and it gives rise to an ultrahigh dielectric permittivity (113.4, at 1 kHz, over 1500% enhancement than that of commercial elastic polyurethane matrix) and excellent comprehensive electromechanical performance, and the optimal comprehensive electromechanical performance reaches to 542.91 MPa-1, which is over 9-fold than that of commercial polyurethane elastic film. An interdigital capacitive strain sensor is designed using the topological structured elastic dielectric nanocomposite. It possesses high initial capacitance density and positive capacitance response with stain, achieving high signal-to-noise ratio, high capacitance response sensitivity, and wide linear range, and it breaks through disadvantages of negative sensitivity and narrow linear range for conventional interdigital strain sensors. The prepared integrated strain sensor arrays are able to measure local strain of convoluted surfaces and monitor the motion of soft actuators in real time, and they would make conditions for intelligent control systems and the study of morphological intelligence.