The development of covalent adaptable liquid crystal networks (LCNs) enabled by introducing dynamic covalent bonds has endowed liquid crystal actuators with self-healing properties and reversible shape programmability, broadening their applications in diverse soft robotic devices. However, the finite molecular design strategy limits the recyclability and the architectural diversity of these materials. Here, a strategy is first reported for fabricating photoresponsive polydisulfide-based covalent adaptable LCNs by ringopening polymerization of cyclic dithiolane groups. Based on the disulfide metathesis, the resulting materials are self-healable, reshapable, and reprogrammable. Importantly, the equilibrium between the polymer backbones and the dithiolane-functionalized monomers enables catalytic depolymerization to recycle monomers, which could significantly weaken the disadvantage of subtractive manufacturing of photomechanical devices. This work rooted in chemistry would provide an economical and environmentally friendly strategy for the fabrication of functional soft robotics with excellent programmability and renewability and beyond.

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Although liquid crystal elastomers (LCEs) have demonstrated various applications in artificial muscles and soft robotics, their inherent flexibility and orientation‐dependent forces limit their functions. For instance, LCEs can sustain a high actuation force when they contract but cannot elongate to drive loads with large displacements. In this study, it is demonstrated that photocontrollable elongation actuation with a large strain can be achieved in polydomain LCEs by programming the crease structures in a well‐defined order to couple the actuation forces. Efficient photoactuation without overheating‐induced damage to the materials is favored, based on the well‐designed photosensitive molecular switch crosslinker via the synergy of photochemical and photothermal effects. The LCE actuator can jack up heavy loads, elongate freely, and contract back to manipulate distant objects. Theoretical analysis based on a finite element simulation of the deformation energy during the actuation process reveals a trade‐off between the abilities of jacking‐up and withstanding load. More importantly, this study simplifies the design of a single material with functions inherent only in other soft robotic devices based on the assembly of multiple modules, thus providing a design strategy for surpassing instinctive properties of conventional soft materials to expand the functions of soft robotics.

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Soft actuators have shown great potential in soft robotic technologies, where complex functions usually originate from fundamental components with a simple motion mode. Therefore, how to convert the simple motion mode to complex motion modes becomes a vital challenge. In contrast to rigid actuators, where the simple motion mode can be converted to complex motion modes by gearing systems and transmission devices, manufacturing assembled soft actuators by splicing different functional building blocks has been considered an effective strategy. However, most of the assembled soft actuators cannot be reconstructed and modified once they have been fabricated because of the limitation of the adhesion methods, making these devices unmodifiable and unreconfigurable and typically thrown away after a single use. Endowing the assembled materials with well-designed functions that the components do not have by designing functional adhesives is also important. Considering that free-standing adhesive tapes can have the features of onsite and repeatable installation and can be integrated with designed functions and shapes, devising assembled actuators using adhesive tape appears to be a feasible approach. Herein, we develop a free-standing functional adhesive tape based on polydisulfides containing photoresponsive azobenzene moieties (PDS-Azo) and utilize the tape to fabricate reconfigurable and spliceable soft actuators. The chemical structures of PDS-Azo tape are carefully designed to obtain an optimized adhesion performance with photothermal functions. Moreover, the tape could show reversible adhesion triggered by either heating or light irradiation. It is demonstrated that the adhesive tape can be utilized to assemble different functional building blocks to develop smart soft devices with reconfigurability.

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