Bioinspired Soft Microactuators by Droplet Microfluidics

Project: Research

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Soft actuators can exhibit continuous deformations, minimize damage under high loads, conformably adapt to complex environments, and allow safe human-machine interactions. Thus, they hold great promise for a range of applications, including artificial muscles, soft robotics, wearable devices, sensing, and biomedicine. However, due to inadequacies in conventional design and fabrication, a long-standing challenge in the development of soft actuators has been the simultaneous achievement of (i) significant actuation for high-payload mechanical work, (ii) diverse shape transformations, (iii) high contrast between material properties in the "on" and "off" states, and (iv) miniaturization. We propose to develop microfiber-type bioinspired soft microactuators (BSMAs) that meet these four requirements. We will combine tunable stiffness as exhibited by sea cucumber (holothurian) dermis and regulatable deformability as exhibited by plant tendrils, to realize BSMAs with high actuation performance and diverse shape transformations, respectively. The BSMAs will consist of hygroscopically responsive microfibers embedded with a discontinuous ribbon of stiff, asymmetric, and hygroscopically inactive microparticles, which will enable a remarkable property contrast between the dehydrated "on" and hydrated "off" states. We propose to use droplet microfluidics to fabricate the BSMAs. Microfluidic fabrication has several advantages, as it enables the precise handling of small volumes of fluids, the accurate production of uniform emulsions, and the freedom to use a variety of materials, which will enable the construction of seamless and miniaturized BSMAs with independently controllable morphology and composition. The innovation of this proposal will be its combination of synergistic bioinspiration and droplet microfluidics to address the respective inadequacies of conventional design and fabrication. We aim to explore the potential of this promising approach to generate highperformance soft actuators. Specifically, we will develop and characterize the proposed approach by fabricating BSMAs made of diatomite-reinforced alginate microfibers embedded with asymmetric trimethylolpropane ethoxylate triacrylate (ETPTA) microparticles. We will then correlate the morphology, composition, mechanical properties, and actuation of these BSMAs with processing parameters and investigate BSMAs' potential applications. The three ingredients – diatomite, alginate, and ETPTA – are selected because of their biocompatibility, commercial availability, and low cost. This project will provide a new and generally applicable method for designing and fabricating next-generation soft actuators. This will be a great advance, as it will enable the precise tailoring of soft actuators' morphologies and properties. The project will also provide a revolutionary type of miniaturized BSMAs with tunable mechanical properties, high-performance actuation, and diverse shape transformability, establishing a foundation for their wider application. 


Project number9048211
Grant typeECS
StatusNot started
Effective start/end date1/01/22 → …