The previously reported gel and polymer actuators require external inputs, such as batteries, circuits, electronic circuits, etc., compared with autonomous motions produced by the living organisms. To realize the spontaneous motions, here, we propose to integrate a power supply, actuators, and control into a single-component self-oscillating hydrogel. We demonstrate self-actuating gel pumps driven by the oscillatory Belousov-Zhabotinsky (BZ) reaction without electronic components. We have developed the volume oscillation of gels synchronized with the BZ reaction (BZ gel). Since the self-actuating gel pumps are driven by chemo-mechanical energy from BZ gels, the self-actuating gel pumps don't require complex wiring designs, energy supply, and assembling. The mechanical work generated by BZ gels is extremely small. We formulated the thermodynamic cycle of BZ gels and maximized mechanical work. We found that pre-stretched BZ gel shows larger mechanical works. We physically separated the BZ gels and working fluid to create practical pumps. By using optimizing mechanical generated by BZ gels, we demonstrated the self-actuating gel pumps that transfer mechanical work through a stretchable elastomer membrane. Machines and robots are essential to guarantee high production rates in industrial supply chains, while consumable electronics became ubiquitous in our daily lives. All these devices belong to the wide field of mechatronics, which encompasses different engineering technologies, such as mechanical, control, electronic, and information engineering. Advances in mechatronics in the last decades led to increasingly smaller and advanced robots and machines. However, such advancement came at the cost of a significant increase in the complexity and intricacy of these systems. It follows that engineers in industries can no longer develop and inspect machines without aids from a computer and other advanced diagnostic tools. Researchers and engineers developing robots and machines face increasing challenges in the design of systems composed by a large number of components, such as complex wiring designs, energy supply, and assembling. Aiming to overcome the complexity, we propose to use active and smart compliant materials that can solve complex tasks using few components and little computation 1,2. Examples include self-stabilizing walkers that use the passive dynamics of their legs and soft grippers that adapt to the shape and stiffness of the grasped object. Herein we propose to move a step forward and blend the power supply, the actuators, and the control into a single-component self-oscillating hydrogel. Driven by chains of chemical reactions, these hydrogels oscillate by direct conversion of chemical energy into mechanical energy, alike self-motion in biological systems 3. Hydrogels capable of self-motion have been presented in the previous work 4-8. However, these oscillating hydrogels require being submerged in a strongly acidic chemical bath, which limits their practical applicability in mobile and wearable robotics....
