Now you see it, now you don't: Thermal vision cameras detect differences in temperature by sensing infrared wavelengths. If a coating could be developed that showed dynamic tuning of the effective temperature, it might be possible to hide objects from infrared sensing. Xu et al. started with a basic Bragg reflector made up of multiple layers of alternating materials with varying refractive index. The authors designed structures that were wavy to begin with so that they could be flattened out by electrical activation. This changed the infrared reflectivity and, thus, the effective temperature of the object observed in its infrared profile. Science , this issue p. 1495

Effective thermal management is critical for the operation of many modern technologies, such as electronic circuits, smart clothing, and building environment control systems. By leveraging the static infrared-reflecting design of the space blanket and drawing inspiration from the dynamic color-changing ability of squid skin, we have developed a composite material with tunable thermoregulatory properties. Our material demonstrates an on/off switching ratio of ~25 for the transmittance, regulates a heat flux of ~36 W/m² with an estimated mechanical power input of ~3 W/m², and features a dynamic environmental setpoint temperature window of ~8 °C. Moreover, the composite can manage one fourth of the metabolic heat flux expected for a sedentary individual and can also modulate localized changes in a wearer’s body temperature by nearly 10-fold. Due to such functionality and associated figures of merit, our material may substantially reduce building energy consumption upon widespread deployment and adoption.

Polydimethylsiloxane-α,ω-diols were used as matrix for barium titanate particles to obtain electroactive elastomeric composites. Filler particles were previously treated with a surfactant to improve the compatibility with and dispersibility in the matrix. The composites, processed as films and crosslinked with methyltriacetoxysilane, were investigated from point of view of the morphology, moisture sorption and thermal properties, as well as mechanical and dielectric behavior. Maximum strain value of 850% at 0.32 MPa and dielectric permittivity of 4.41 at 10 Hz and 20 °C were obtained. Two parameters of interest for potential future application of such materials in electromechanical devices (actuation or harvesting), electromechanical sensitivity and harvesting energy capacity, were estimated and discussed in correlation with the molecular mass of the polymeric matrix and the content of the active filler

Dielectric elastomers were prepared on the basis of high molecular weight polydimethylsiloxane-α,ω-diol filled with barium titanate particles having well-defined size and morphology.