Complex multiphase organohydrogels with programmable mechanics toward adaptive soft-matter machines

Abstract

Many biological organisms can tune their mechanical properties to adapt to environments in multistable modes, but the current synthetic materials, with bistable states, have a limited ability to alter mechanical stiffness. Here, we constructed programmable organohydrogels with multistable mechanical states by an on-demand modular assembly of noneutectic phase transition components inside microrganogel inclusions. The resultant multiphase organohydrogel exhibits precisely controllable thermo-induced stepwise switching (i.e., triple, quadruple, and quintuple switching) mechanics and a self-healing property. The organohydrogel was introduced into the design of soft-matter machines, yielding a soft gripper with adaptive grasping through stiffness matching with various objects under pneumatic-thermal hybrid actuation. Meanwhile, a programmable adhesion of octopus-inspired robotic tentacles on a wide range of surface morphologies was realized. These results demonstrated the applicability of these organohydrogels in lifelike soft robotics in unconstructed and human body environments.

Stimuli‐Responsive Nanocomposite Hydrogels for Biomedical Applications

“…Herein, instead of relying on stimuli conventionally explored for reversible stiffening‐softening (i.e., pH, temperature or light), in biological systems mechanical cues can simultaneously function as inputs and outputs, where an initial mechanical loading triggers stiffening of the network. [ 186 ] This mechanism has recently inspired the development of strain‐induced stiffening hydrogels where supramolecular protein nanocages are leveraged as multivalent sacrificial crosslinkers of polymeric networks. [ 187 ] To do so, azide‐functionalized polyisocyanide polymers were crosslinked with DBCO‐modified virus‐mimetic capsids exhibiting pH‐responsive self‐assembly.…”

Fluid‐Driven Soft CoboSkin for Safer Human–Robot Collaboration: Fabrication and Adaptation

“…[27] In addition, the squid with its tentacles and the octopus is able to selectively stiffen parts of its arms to use them as a modifiable skeleton for both quick escape and fierce predation. [28] The stiffness of tongues could change in different situations, such as eating and speaking. [29,30] Stiffness turning is a kind of environmental adaptation of biological behavior which can be effectively beneficial for creatures' interaction with the environment.…”

Mechanics of Crater-Enabled Soft Dry Adhesives: A Review

“…The same group also provided a feasible solution for preventing air leakage when gripping rough surfaces by programming the compliance of the sucker. The sucker was made of electrically responsive organohydrogel, which softened under high voltage, giving rise to conformable contact with rough surfaces ( Figure 4C) (Zhuo et al, 2020). Theoretical analysis and experimental measurements have been carried out to understand both the attachment and detachment behaviors of suction cups.…”