A soft biomolecule actuator based on a highly functionalized bacterial cellulose nano-fiber network with carboxylic acid groups.

Upcoming human-related applications such as soft wearable electronics, flexible haptic systems, and active bio-medical devices will require bio-friendly actuating materials. Here, we report a soft biomolecule actuator based on carboxylated bacterial cellulose (CBC), ionic liquid (IL), and poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) ( PEDOT: PSS) electrodes. Soft and biocompatible polymer-IL composites were prepared via doping of CBC with ILs. The highly conductive PEDOT: PSS layers were deposited on both sides of the CBC-IL membranes by a dip-coating technique to yield a sandwiched actuator system. Ionic conductivity and ionic exchange capacity of the CBC membrane can be increased up to 22.8 times and 1.5 times compared with pristine bacterial cellulose (BC), respectively, resulting in 8 times large bending deformation than the pure BC actuators with metallic electrodes in an open air environment. The developed CBC-IL actuators show significant progress in the development of biocompatible and soft actuating materials with quick response, low operating voltage and comparatively large bending deformation.

Well-aligned nano-fiberous membranes based on three-pole electrospinning with channel electrode.

Three-pole electrospinning devices integrated with a blade-cage collector were developed to fabricate well-aligned nano-fiberous membranes. The proposed three-pole configuration with a channel electrode can be a powerful tool in aligning nano-fibers with regular diameter because the generated electric field can be accurately controlled without severe fluctuation in comparison with other methods. The three-pole electrospinning method is also valid for industrial mass production and accurate diameter control of the aligned nano-fibers.

Electro-active Polymer Actuator Based on Sulfonated Polyimide with Highly Conductive Silver Electrodes Via Self-metallization.

We report here a facile synthesis of high performance electro-active polymer actuator based on a sulfonated polyimide with well-defined silver electrodes via self-metallization. The proposed method greatly reduces fabrication time and cost, and obviates a cation exchange process required in the fabrication of ionic polymer-metal composite actuators. Also, the self-metallized silver electrodes exhibit outstanding metal-polymer adhesion with high conductivity, resulting in substantially larger tip displacements compared with Nafion-based actuators.

An eco-friendly ultra-high performance ionic artificial muscle based on poly(2-acrylamido-2-methyl-1-propanesulfonic acid) and carboxylated bacterial cellulose.

Eco-friendly high-performance ionic artificial muscles have recently attracted enormous interest because of their applications in human friendly electronics including flexible haptic devices, wearable electronics, disposal or implantable biomedical devices, and biomimetic robots. Here, we report an eco-friendly ionic polymer actuator based on poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), carboxylated bacterial cellulose (CBC), and an ionic liquid (IL) as a plasticizer, demonstrating ultra-high electromechanical deformation, quick response, and excellent durability. The proposed CBC-IL-PAMPS composite membrane exhibits an increased ionic conductivity, tensile strength, and specific capacitance of up to 32.5%, 44.9%, and 160%, respectively, thereby resulting in 4.5 times larger bending deformation than that of the CBC-IL actuator, all of which are due to the cross-linking and ionic interactions among the sulfonate functional groups of PAMPS, carboxylate functional groups of CBC, and the IL ([EMIM][BF4]). The developed electro-chemo-mechanical CBC-IL-PAMPS actuator is a promising candidate for human friendly electronics such as artificial muscles, wearable devices, biomedical devices, and biomimetic robots due to its high actuation performance, low operating voltage, and fast response as well as durable operation.

Durable and water-floatable ionic polymer actuator with hydrophobic and asymmetrically laser-scribed reduced graphene oxide paper electrodes.

Ionic polymer actuators driven by electrical stimuli have been widely investigated for use in practical applications such as bioinspired robots, sensors, and biomedical devices. However, conventional ionic polymer-metal composite actuators have a serious drawback of poor durability under long-term actuation in open air, mainly because of the leakage of the inner electrolyte and hydrated cations through cracks in the metallic electrodes. Here, we developed a highly durable and water-floatable ionic polymer artificial muscle by employing hydrophobic and asymmetrically laser-scribed reduced graphene oxide paper electrodes (HLrGOP). The highly conductive, flexible, and cost-effective HLrGOP electrodes have asymmetrically smooth hydrophobic outer and rough inner surfaces, resulting in liquid-impermeable and water-floatable functionalities and strong bonding between an ionic polymer and the electrodes. More interestingly, the HLrGOP electrode, which has a unique functionality to prevent the leakage of the vaporized or liquid electrolyte and mobile ions during electrical stimuli, greatly contributes to an exceptionally durable ionic polymer-graphene composite actuator that is a prerequisite for practical applications in active biomedical devices, biomimetic robots, touch-feedback haptic systems, and flexible soft electronics.