Human ingenuity has found a multitude of ways to manipulate fluids across different applications. However, the fundamentals of fluid propulsion change when moving from the macro‐ to the microscale. Viscous forces dominate inertial forces rendering successful methods at the macroscale ineffective for microscale fluid propulsion. Nature however has found a solution; microscopic active organelles protruding from cells that feature intricate beating patterns: cilia. Cilia succeed in propelling fluids at small dimensions; hence they have served as a source of inspiration for microfluidic applications. Mimicking biological cilia however remains challenging due to their small size and the required kinematic complexity. Recent advances have pushed artificial cilia technology forward, yet discrepancies with natural cilia still exists. This study identifies this gap by analyzing artificial cilia technology and benchmarking them to natural cilia, to pinpoint the remaining design and manufacturing challenges that lay at the basis of the disparity with nature.

Inflatable actuators are regularly used to induce large complex deformations in soft robotic systems. Their actuation speed is typically low, as it takes time for fluids to be pushed through narrow pressure supply tubes. To overcome this limitation, we take inspiration from nature and create actuators that can suddenly release build up elastic energy, by means of breaking a physical bond. Where in nature these ruptures are irreversible, here we use the reversible adhesion of a suction cup to accomplish the same behavior. First, we show that the released elastic energy originates from an adiabatic transition from the constrained to the free inflation curve of the actuator. Next, we numerically analyse this process and give design considerations for maximizing energy release. Lastly, we build a prototype actuator that displays this type of energy release and demonstrate that it can be used for jumping.