Octopus-inspired deception and signaling systems from an exceptionally-stable acene variant.

Multifunctional platforms that can dynamically modulate their color and appearance have attracted attention for applications as varied as displays, signaling, camouflage, anti-counterfeiting, sensing, biomedical imaging, energy conservation, and robotics. Within this context, the development of camouflage systems with tunable spectroscopic and fluorescent properties that span the ultraviolet, visible, and near-infrared spectral regions has remained exceedingly challenging because of frequently competing materials and device design requirements. Herein, we draw inspiration from the unique blue rings of the Hapalochlaena lunulata octopus for the development of deception and signaling systems that resolve these critical challenges. As the active material, our actuator-type systems incorporate a readily-prepared and easily-processable nonacene-like molecule with an ambient-atmosphere stability that exceeds the state-of-the-art for comparable acenes by orders of magnitude. Devices from this active material feature a powerful and unique combination of advantages, including straightforward benchtop fabrication, competitive baseline performance metrics, robustness during cycling with the capacity for autonomous self-repair, and multiple dynamic multispectral operating modes. When considered together, the described exciting discoveries point to new scientific and technological opportunities in the areas of functional organic materials, reconfigurable soft actuators, and adaptive photonic systems.

Structure-function relationships for squid skin-inspired wearable thermoregulatory materials.

Wearable thermoregulatory technologies have attracted widespread attention because of their potential for impacting individual physiological comfort and for reducing building energy consumption. Within this context, the study of materials and systems that can merge the advantageous characteristics of both active and passive operating modes has proven particularly attractive. Accordingly, our laboratory has drawn inspiration from the appearance-changing skin of Loliginidae (inshore squids) for the introduction of a unique class of dynamic thermoregulatory composite materials with outstanding figures of merit. Herein, we demonstrate a straightforward approach for experimentally controlling and computationally predicting the adaptive infrared properties of such bioinspired composites, thereby enabling the development and validation of robust structure-function relationships for the composites. Our findings may help unlock the potential of not only the described materials but also comparable systems for applications as varied as thermoregulatory wearables, food packaging, infrared camouflage, soft robotics, and biomedical sensing.

Surface Modification on Pd-TiO2 Hybrid Nanostructures towards Highly Efficient H2 Production from Catalytic Formic Acid Decomposition.

Metal-containing nanocrystals with well-designed surface structures represent a class of model systems for revealing the fundamental physical and chemical processes involved in heterogeneous catalysis. Herein it is shown how surface modification can be utilized as an efficient strategy for controlling the surface electronic state of catalysts and, thus, for tuning their catalytic activity. As model catalysts, the Pd-tetrahedron-TiO2 nanostructures, modified on the surface with different foreign atoms, showed a varied activity in the catalytic decomposition of formic acid towards H2 production. The catalytic activity increases with a reduction in the work function of modified atoms; this reduction can be well explained by a surface polarization mechanism. In this hybrid system, the difference in the work functions of Pd and modified atoms results in surface polarization on the Pd surface and, thus, in the tuning of its charge state. Together with the Schottky junction between TiO2 and metals, the tuned charge state enables the promotion of catalytic efficiency in the catalytic decomposition of formic acid to H2 and CO2 .