Complex-chamber hydrogel actuators based on strong interfacial adhesion for fluid-driven multi-degree-of-freedom motions

Hydrogel actuators with fast responsive speed, large driving power, diverse motions, superior mechanical properties and good environmental adaptability could be a suitable candidate for complex-task scenarios. However, a complete aggregation of these above characteristics is rarely reported, due to limitations from processing methods, raw materials and structural configuration of present hydrogel actuators. Herein we designed and fabricated complex-chamber-structure hydrogel actuators basing on soft interfacial adhesion of aluminum hydroxide nanocomposite hydrogels without any mold, template and valuable equipment, demonstrating that this method possessed simple, facile and inexpensive features. These composite hydrogels showed high tensile (0.5–1.0 MPa) and compressive (2–15 MPa) resistance properties, much higher than those of previously reported fluid-driven hydrogel actuators, which meant that our hydrogel actuators could have a higher cargo loading capacity. The cavity-structure soft actuators owned superior sealability and self-recoverability, and could give rapid uniaxial expansion and multidirectional large-scale bending under fluid actuation. Furthermore, those actuators with sucker structure were able to transfer heavy objects (e.g. 80 g glass plate and 180 g billiard ball) from water to air, and also move a plastic plate from back to right in three-dimensional space, indicating that this complex-cavity hydrogel actuators could suit to multi-task scenarios. The exquisitely assembled process of intricate chamber structure will offer a novel approach for hydrogel actuators with diversified driving functions.