A Programmable Actuator as Synthetic Earthworm.

Natural earthworm with ability of loosening soils that favors sustainable agriculture has inspired a worldwide interests in the design of intelligent actuators. Given the inability to carry heavy loads and uncontrolled deformation, the vast majority of actuators can only perform simple tasks by bending, contraction, or elongation. Herein, we present a degradable actuator with ability of deforming in desired ways, which successfully mimics the burrowing activities of earthworms to loosen soils with increased soil porosity by digging, grabbing, and lifting the soil when it receives rains. Such a scarifying actuator is made of degradable cellulose acetate and uncrosslinked polyacrylamideviaswelling-photopolymerizing method. The water absorption of polyacrylamidein moisture conditions causes a rapid and remarkable bending. Such a mechanical bending can be controlled in specific areas of the cellulose acetate film if polyacrylamide is polymerized in a patterned way, so as to generate complicated deformations of the whole cellulose acetate. Patterning polyacrylamide within cellulose acetate is achieved based on reversible surface protection by means of pen writing, rather than the traditional masking techniques.The water-induced deformation of programmable cellulose-based actuators is well preserved in soil, which is appropriate for promoting the rain diffusion as well as the root breath. This article is protected by copyright. All rights reserved.