Soft robots have received an increasing attention due to their advantages of high flexibility and safety for human operators but the fabrication is a challenge. Recently, 3D printing has been used as a key technology to fabricate soft robots because of high quality and printing multiple materials at the same time. Functional soft materials are particularly well suited for soft robotics due to a wide range of stimulants and sensitive demonstration of large deformations, high motion complexities and varied multi-functionalities. This review comprises a detailed survey of 3D printing in soft robotics. The development of key 3D printing technologies and new materials along with composites for soft robotic applications is investigated. A brief summary of 3D-printed soft devices suitable for medical to industrial applications is also included. The growing research on both 3D printing and soft robotics needs a summary of the major reported studies and the authors believe that this review article serves the purpose.

Owing to the increasing interest in the nonvolatile memory devices, resistive switching based on hybrid nanocomposite of a 2D material, molybdenum disulphide (MoS₂) and polyvinyl alcohol (PVA) is explored in this work. As a proof of concept, we have demonstrated the fabrication of a memory device with the configuration of PET/Ag/MoS₂-PVA/Ag via an all printed, hybrid, and state of the art fabrication approach. Bottom Ag electrodes, active layer of hybrid MoS₂-PVA nanocomposite and top Ag electrode are deposited by reverse offset, electrohydrodynamic (EHD) atomization and electrohydrodynamic (EHD) patterning respectively. The fabricated device displayed characteristic bistable, nonvolatile and rewritable resistive switching behavior at a low operating voltage. A decent off/on ratio, high retention time, and large endurance of 1.28 × 10², 10⁵ sec and 1000 voltage sweeps were recorded respectively. Double logarithmic curve satisfy the trap controlled space charge limited current (TCSCLC) model in high resistance state (HRS) and ohmic model in low resistance state (LRS). Bendability test at various bending diameters (50-2 mm) for 1500 cycles was carried out to show the mechanical robustness of fabricated device.

Two dimensional (2D) materials have offered unique electrical, chemical, mechanical and physical properties over the past decade owing to their ultrathin, flexible, and multilayer structure. These layered materials are being used in numerous electronic devices for various applications, and this review will specifically focus on the resistive random access memories (RRAMs) based on 2D materials and their nanocomposites. This study presents the device structures, conduction mechanisms, resistive switching properties, fabrication technologies, challenges and future aspects of 2D materials based RRAMs. Graphene, derivatives of graphene and MoS₂ have been the major contributors among 2D materials for the application of RRAMs however, other members of this family such as hBN, MoSe₂, WS₂, and WSe₂ have also been inspected more recently as the functional materials of nonvolatile RRAM devices. Conduction in these devices is usually dominated by either the penetration of metallic ions or migration of intrinsic species. Most prominent advantages offered by RRAM devices based on 2D materials include fast switching speed (< 10 ns), less power losses (10 pJ), lower threshold voltage (< 1V) long retention time (> 10 years), high electrical endurance (> 10⁸ voltage cycles) and extended mechanical robustness (500 bending cycles). Resistive switching properties of 2D materials have been further enhanced by blending them with metallic nanoparticles, organic polymers and inorganic semiconductors in various forms.

Organic–inorganic hybrid nanocomposites are an attractive choice for various electronic device applications.