The effect of MWCNT content on electropolymerization of PPy film and electromechanical behavior of PPy electrode-based soft actuators

Carbon-Based Nanomaterials Electrodes of Ionic Soft Actuators: From Initial 1D Structure to 3D Composite Structure for Flexible Intelligent Devices

With the rapid development of autonomous and intelligent devices driven by soft actuators, ion soft actuators in flexible intelligent devices have several advantages over other actuators, including their light weight, low voltage drive, large strain, good flexibility, fast response, etc. Traditional ionic polymer metal composites have received a lot of attention over the past decades, but they suffer from poor driving performance and short service lives since the precious metal electrodes are not only expensive, heavy, and labor-intensive, but also prone to cracking with repeated actuation. As excellent candidates for the electrode materials of ionic soft actuators, carbon-based nanomaterials have received a lot of interest because of their plentiful reserves, low cost, and excellent mechanical, electrical, and electrochemical properties. This research reviewed carbon-based nanomaterial electrodes of ion soft actuators for flexible smart devices from a fresh perspective from 1D to 3D combinations. The design of the electrode structure is introduced after the driving mechanism of ionic soft actuators. The details of ionic soft actuator electrodes made of carbon-based nanomaterials are then provided. Additionally, a summary of applications for flexible intelligent devices is provided. Finally, suggestions for challenges and prospects are made to offer direction and inspiration for further development.

Self-extinguished and flexible cation exchange membranes based on modified K-Carrageenan/PVA double network hydrogels for electrochemical applications

It is highly desired and yet challenging to develop eco-friendly cation exchange membranes with a combination of good mechanical, electrochemical, and biocompatible properties with a rational economic efficiency for given applications. In this study, new biocompatible double network (DN) hydrogels were prepared based on a blend of modified K-Carrageenan (KC) and polyvinyl alcohol (PVA). Acrylic acid (AA)-grafted KC (KC-g-(PAA)) and (AA-co-tertbutyl acrylate (TBA))-grafted KC (KC-g-P(AA-co-TBA)) were synthesized through an in situ free radical copolymerization. The grafted copolymers were blended with PVA and mixed with ZrOCl₂/KCl and glutaraldehyde (Glu) as the physical and chemical cross-linkers, respectively to produce KC-g-P(AA)/PVA and KC-g-P(AA-co-TBA)/PVA DN hydrogels. The membranes were prepared by a solution casting method. Various techniques were carried out to compare the structural, thermal, mechanical, flammability, and electrochemical properties of the membranes with those of the cross-linked KC, PVA, and KC/PVA membranes. The KC-g-P(AA-co-TBA)/PVA DN membrane showed more desirable properties as the cation exchange membrane with water uptake of 70.7 %, ion exchange capacity of 0.47 meq H⁺ /g, the ionic conductivity of 1.99 × 10^-2 S/cm², and elongation at break of 71.8 %. The prepared biopolymer membrane is very cost-effective and self-extinguished with admissible conductivity for electrochemical applications.

Designing flexible, smart and self-sustainable supercapacitors for portable/wearable electronics: from conductive polymers

The rapid development of portable/wearable electronics proposes new demands for energy storage devices, which are flexibility, smart functions and long-time outdoor operation. Supercapacitors (SCs) show great potential in portable/wearable applications, and the recently developed flexible, smart and self-sustainable supercapacitors greatly meet the above demands. In these supercapacitors, conductive polymers (CPs) are widely applied due to their high flexibility, conductivity, pseudo-capacitance, smart characteristics and moderate preparation conditions. Herein, we'd like to introduce the CP-based flexible, smart and self-sustainable supercapacitors for portable/wearable electronics. This review first summarizes the flexible SCs based on CPs and their composites with carbon materials and metal compounds. The smart supercapacitors, i.e., electrochromic, electrochemical actuated, stretchable, self-healing and stimuli-sensitive ones, are then presented. The self-sustainable SCs which integrate SC units with energy-harvesting units in one compact configuration are also introduced. The last section highlights some current challenges and future perspectives of this thriving field.

Carbon Nanostructures for Actuators: An Overview of Recent Developments

In recent decades, micro and nanoscale technologies have become cutting-edge frontiers in material science and device developments. This worldwide trend has induced further improvements in actuator production with enhanced performance. A main role has been played by nanostructured carbon-based materials, i.e., carbon nanotubes and graphene, due to their intrinsic properties and easy functionalization. Moreover, the nanoscale decoration of these materials has led to the design of doped and decorated carbon-based devices effectively used as actuators incorporating metals and metal-based structures. This review provides an overview and discussion of the overall process for producing AC actuators using nanostructured, doped, and decorated carbon materials. It highlights the differences and common aspects that make carbon materials one of the most promising resources in the field of actuators.

3D structured polypyrrole/reduced graphene oxide (PPy/rGO)-based electrode ionic soft actuators with improved actuation performance

We report a facile approach to fabricate 3D polypyrrole/reduced graphene oxide (PPy/rGO)-based electrodes for Nafion-based ionic soft actuators.