An important trend in electronics involves the development of materials, mechanical designs and manufacturing strategies that enable the use of unconventional substrates, such as polymer films, metal foils, paper sheets or rubber slabs. The last possibility is particularly challenging because the systems must accommodate not only bending but also stretching. Although several approaches are available for the electronics, a persistent difficulty is in power supplies that have similar mechanical properties, to allow their co-integration with the electronics. Here we introduce a set of materials and design concepts for a rechargeable lithium ion battery technology that exploits thin, low modulus silicone elastomers as substrates, with a segmented design in the active materials, and unusual 'self-similar' interconnect structures between them. The result enables reversible levels of stretchability up to 300%, while maintaining capacity densities of B1.1 mAh cm À 2 . Stretchable wireless power transmission systems provide the means to charge these types of batteries, without direct physical contact.

Negative-index metamaterials (NIMs) are engineered structures with optical properties that cannot be obtained in naturally occurring materials. Recent work has demonstrated that focused ion beam and layer-by-layer electron-beam lithography can be used to pattern the necessary nanoscale features over small areas (hundreds of µm(2)) for metamaterials with three-dimensional layouts and interesting characteristics, including negative-index behaviour in the optical regime. A key challenge is in the fabrication of such three-dimensional NIMs with sizes and at throughputs necessary for many realistic applications (including lenses, resonators and other photonic components). We report a simple printing approach capable of forming large-area, high-quality NIMs with three-dimensional, multilayer formats. Here, a silicon wafer with deep, nanoscale patterns of surface relief serves as a reusable stamp. Blanket deposition of alternating layers of silver and magnesium fluoride onto such a stamp represents a process for 'inking' it with thick, multilayer assemblies. Transfer printing this ink material onto rigid or flexible substrates completes the fabrication in a high-throughput manner. Experimental measurements and simulation results show that macroscale, three-dimensional NIMs (>75 cm(2)) nano-manufactured in this way exhibit a strong, negative index of refraction in the near-infrared spectral range, with excellent figures of merit.

A phase diagram of a water−poly(oxyethylene) oleyl ether (POlE) system was constructed as a function of poly(oxyethylene) chain length at 25 °C. The POlEs contain a highly pure oleyl group, whose purity is above 99.7%. The POlEs are in a liquid state over a wide range of composition. The increase in the poly(oxyethylene) (EO) chain of POlE corresponds to the increase in the curvature of surfactant layer toward water or the increase in HLB (hydrophile−lipophile balance) number of the surfactant. Various self-organizing structures were found:  hexagonal and lamellar lquid crystals, four kinds of isotropic liquid crystals, a sponge phase, and reverse hexagonal liquid crystal. The phase transition between normal hexagonal and lamellar liquid crystals were investigated at constant volume fraction of the oleyl group in system by means of small-angle X-ray scattering. Correlation among the phase behavior, the packing of oleyl chain in self-organizing structures, and the HLB of POlE is discussed. The effect of temperature on the phase behavior in the present system is also discussed.

The field of plasmonics has emerged as an interesting area for fundamental studies, with important application possibilities in miniaturized photonic components. Plasmonic crystals are of particular relevance because of large field enhancements and extraordinary transmission that arise from plasmonic interactions between periodic arrays of metallic elements. Here we report methods to enhance and modify the plasmonic resonances in such structures by strongly coupling them to optical modes of Fabry-Perot type cavities. First, we illustrate a type of plasmonic, narrow-band (~15 nm), high-contrast ( > 20 dB) absorber and an opto-fluidic modulator based on this component. second, we use optimized samples as substrates to achieve strong amplification ( > 350%) and modulation ( > 4×) of surface-enhanced Raman scattering from surface-bound monolayers. Cavity-coupling strategies appear to be useful not only in these two examples, but also in applications of plasmonics for optoelectronics, photovoltaics and related technologies.

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