Morphable three-dimensional electronic mesofliers capable of on-demand unfolding

Development of miniaturized three-dimensional (3D) fliers with integrated functional components has important implications to a diverse range of engineering areas. Among the various active and passive miniaturized 3D fliers reported previously, a class of 3D electronic fliers inspired by wind-dispersed seeds show promising potentials, owing to the lightweight and noiseless features, aside from the stable rotational fall associated with a low falling velocity. While on-demand shape-morphing capabilities are essential for those 3D electronic fliers, the realization of such miniaturized systems remains very challenging, due to the lack of fast-response 3D actuators that can be seamlessly integrated with 3D electronic fliers. Here we develop a type of morphable 3D mesofliers with shape memory polymer (SMP)-based electrothermal actuators, capable of large degree of actuation deformations, with a fast response (e.g., ∼1 s). Integration of functional components, including sensors, controllers, and chip batteries, enables development of intelligent 3D mesoflier systems that can achieve the on-demand unfolding, triggered by the processing of real-time sensed information (e.g., acceleration and humidity data). Such intelligent electronic mesofliers are capable of both the low-air-drag rising and the low-velocity falling, and thereby, can be used to measure the humidity fields in a wide 3D space by simple hand throwing, according to our demonstrations. The developed electronic mesofliers can also be integrated with other types of physical/chemical sensors for uses in different application scenarios. [Figure not available: see fulltext.].