Stretchable pumps for soft machines

Machines made of soft materials bridge life sciences and engineering. Advances in soft materials have led to skin-like sensors and muscle-like actuators for soft robots and wearable devices. Flexible or stretchable counterparts of most key mechatronic components have been developed, principally using fluidically driven systems. other reported mechanisms include electrostatic, stimuli-responsive gels and thermally responsive materials such as liquid metals and shape-memory polymers. Despite the widespread use of fluidic actuation, there have been few soft counterparts of pumps or compressors, limiting the portability and autonomy of soft machines. Here we describe a class of soft-matter bidirectional pumps based on charge-injection electrohydrodynamics. These solid-state pumps are flexible, stretchable, modular, scalable, quiet and rapid. By integrating the pump into a glove, we demonstrate wearable active thermal management. Embedding the pump in an inflatable structure produces a self-contained fluidic ‘muscle’. The stretchable pumps have potential uses in wearable laboratory-on-a-chip and microfluidic sensors, thermally active clothing and autonomous soft robots.