Plasticized Polyvinyl Chloride Gel Research Articles

High performance PVC/ [AMI]mNTF2 ionic gel sensors for smart wearable applications

Plasticized polyvinyl chloride (PVC) gel as an electroactive polymer material has attracted increasing interest for the construction of flexible devices with the integration of actuation and self-sensing. However, the insufficient sensing ability of traditional PVC gels limits their applications. In this paper, a PVC ionic gel sensor based on the physical blending of PVC gel and the ionic liquid 1-allyl-3-methylimidazolium bisimide ([AMI]mNTF2) is presented. With the addition of ionic liquids, the PVC molecular chains and ions formed stable conductive pathways, resulting in increased conductivity and sensing performance of the PVC gel. The proposed sensor exhibits excellent sensing properties of high resolution (0.12 %) and fast response time (95 ms), along with high sensitivity (GF=27.8), which is more than seven times that of the traditional PVC gel. Furthermore, it was successfully utilized for human motion detection and remote control of a robotic hand, demonstrating the feasibility of the sensor for smart wearable applications in the future.

Carbon Nanotube-Doped 3D-Printed Silicone Electrode for Manufacturing Multilayer Porous Plasticized Polyvinyl Chloride Gel Artificial Muscles.

Plasticized polyvinyl chloride (PVC) gel has large deformation under an applied external electrical field and high driving stability in air and is a candidate artificial muscle material for manufacturing a flexible actuator. A porous PVC gel actuator consists of a mesh positive pole, a planar negative pole, and a PVC gel core layer. The current casting method is only suitable for manufacturing simple 2D structures, and it is difficult to produce multilayer porous structures. This study investigated the feasibility of a 3D-printed carbon nanotube-doped silicone electrode for manufacturing multilayer porous PVC gel artificial muscle. Carbon nanotube-doped silicone (CNT-PDMS) composite inks were developed for printing electrode layers of PVC gel artificial muscles. The parameters for the printing plane and mesh electrodes were explored theoretically and experimentally. We produced a CNT-PDMS electrode and PVC gel via integrated printing to manufacture multilayer porous PVC artificial muscle and verified its good performance.

Broadening Bandwidth in a Semi-Active Vibration Absorption System Utilizing Stacked Polyvinyl Chloride Gel Actuators.

Plasticized polyvinyl chloride (PVC) gel is a new soft and smart material, whose potential in electroactive variable stiffness can be used for vibration control in soft robotic systems. In this paper, a new semi-active vibration absorber is developed by stacking PVC gel actuator units. The absorption bandwidth of a single PVC gel absorber covers the range of three natural frequencies (76.5 Hz, 95 Hz, 124 Hz) of a rectangular steel plate in vibration attenuation. The maximum reduction percentage in acceleration amplitude is 63%. With stacked PVC gel actuator units, the absorption bandwidth can be shifted and obviously broadened.

Stretching-insensitive stretchable and biocompatible triboelectric nanogenerators using plasticized PVC gel and graphene electrode for body-integrated touch sensor

Triboelectric nanogenerators (TENG) can generate strong electrical signals even with low frequencies and weak forces, thus research has been conducted to use them as wearable, body-attachable, and body-embeddable devices using biomechanical energies. For this reason, the TENG components, such as dielectric materials and electrodes, should be stretchable. A stretchable and biocompatible single electrode TENG based on plasticized polyvinyl chloride (PVC) gel with a graphene electrode is fabricated. PVC gel is a suitable stretchable TENG dielectric material owing to its high stretchability, dielectric constant, and tribo-negative properties, and graphene is a highly conductive electrode. Graphene and PVC gel-based stretchable and biocompatible TENGs display excellent electrical outputs (48 V, 2.5 μA, and 0.49 W/m2). The electrical resistance range of the electrode which does not affect the TENG output performance, and a stretching-insensitive TENG with approximately 50% stretching rate is successfully demonstrated through this study. In addition, both PVC gel and graphene are biocompatible. These stretching-insensitive and biocompatible TENGs may be used as a self-powered touch sensor that can be integrated into the human body.

Effect of ionic liquids as additives for improving the performance of plasticized PVC gel actuators

Dielectric gels are low-density materials that exhibit a mechanical reaction to electric stimuli. They have recently attracted attention for their potential applications in actuators for wearable robotics. In order to lower the driving voltages of actuators consisting of polyvinyl chloride (PVC) gels (PVC gels with a plasticizer), we studied the generated strain of PVC gel actuators with four types of ionic liquids (ILs) additives: trihexyltetradecyl phosphonium chloride (THTDPCl), tetradodecylammonium chloride (TDACl ), tributylmethyl ammonium chloride (TBMACl), and 1-Butyl-3-mthylimidazolium hexafluorophosphate (BMIMPF6). We found that the actuator responses for PVC gels with additives of 0.01 wt% THTDPCl and TDACl were almost two times larger than those for PVC gels without ILs at low applied voltages ranging from 200 to 600 V. Conversely, the displacement responses of PVC gels with the same IL content but of TBMACl and BMIMPF6 were lower than those of gels without ILs. We studied the electrochemical properties of PVC gels with ILs and proposed an improved electromechanical model based on one proposed in a previous study. Based on the proposed electromechanical model, the effect of the IL additives for lowering the driving voltage can be clearly described.

High-performance polyvinyl chloride gel artificial muscle actuator with graphene oxide and plasticizer

A transparent and electroactive plasticized polyvinyl chloride (PVC) gel was investigated to use as a soft actuator for artificial muscle applications. PVC gels were prepared with varying plasticizer (dibutyl adipate, DBA) content. The prepared PVC gels were characterized using Fourier-transform infrared spectroscopy, thermogravimetric analysis, and dynamic mechanical analysis. The DBA content in the PVC gel was shown to have an inverse relationship with both the storage and loss modulus. The electromechanical performance of PVC gels was demonstrated for both single-layer and stacked multi-layer actuators. When voltage was applied to a single-layer actuator and then increased, the maximum displacement of PVC gels (for PVC/DBA ratios of 1:4, 1:6, and 1:8) was increased from 105.19, 123.67, and 135.55 µm (at 0.5 kV) to 140.93, 157.13, and 172.94 µm (at 1.0 kV) to 145.03, 191.34, and 212.84 µm (at 1.5 kV), respectively. The effects of graphene oxide (GO) addition in the PVC gel were also investigated. The inclusion of GO (0.1 wt.%) provided an approximate 20% enhancement of displacement and 41% increase in force production, and a 36% increase in power output for the PVC/GO gel over traditional plasticizer only PVC gel. The proposed PVC/GO gel actuator may have promising applications in artificial muscle, small mechanical devices, optics, and various opto-electro-mechanical devices due to its low-profile, transparency, and electrical response characteristics.

Electrical properties and electromechanical modeling of plasticized PVC gel actuators

We studied the detailed electrochemical and electromechanical properties of a polyvinyl chloride (PVC) gel with dibutyladipate (DBA) as a plasticizer and developed an electromechanical model based on the electrochemical data. We evaluated the electric deformation of the PVC gel by the bending displacement response of the PVC gel strip when a square-wave voltage is applied. For every electrode, the bending responses were to the anode side and increased with the applied voltage. The bending response of the PVC gel is considered to be due to the electric creep movement on the anode surface. We checked this result by optical microscopy. We studied the electrochemical impedance measurements of the PVC gel under bias voltages and the voltage–current and voltage–displacement measurements in response to a triangle-wave voltage. Based on the above electromechanical and electrochemical experimental results, we developed a deformation model of the PVC gel where the electric bending response is basically due to the electrochemical formation of the solvent-rich layer and its deformation from the Maxwell stress. We estimated the displacements with applied voltages of 200 and 1000 V, and the model results were in good agreement with the experimental results despite the rough estimation.

Understanding the electro-stimulated deformation of PVC gel by in situ Raman spectroscopy

Electro-responsive materials are of promising applications in microdevices. A dioctyl terephthalate (DOTP) plasticized polyvinyl chloride (PVC) gel actuator driven by unilateral electrodes was proposed, with which the dynamical creeping deformation of the gel around the anode by electro-stimulation was investigated by in situ Raman spectroscopy. The obtained results reveal that the intensity of the band at 1612 cm−1 was linearly correlated to the ratio of DOTP in PVC gel. The plasticizer concentration evolved after an external electro-stimulation was applied, which indicates the migration of plasticizer around the anode. The migration of the plasticizers to the two sides of the anode consequently drives the deformation of the PVC gel. The memory effect of deformation is due to the residuals of the plasticizers out of their original positions after the removal of electro-stimulation. The understanding of the dynamical deformation of PVC gel in response to electro-stimulations may be helpful for the designing of novel electric actuators.

PVC gel soft actuator-based wearable assist wear for hip joint support during walking

Plasticized polyvinyl chloride (PVC) gel and mesh electrode-based soft actuators have considerable potential to provide new types of artificial muscle, exhibiting similar responsiveness to biological muscle in air, >10% deformation, >90 kPa output stress, variable stiffness, long cycle life (>5 million cycles), and low power consumption. We have designed and fabricated a prototype of walking assist wear using the PVC gel actuator in previous study. The system has several advantages compared with traditional motor-based exoskeletons, including lower weight and power consumption, and no requirement for rigid external structures that constrain the wearer’s joints. In this study, we designed and established a control and power system to making the whole system portable and wearable outdoors. And we designed two control strategies based on the characteristics of the assist wear and the biological kinematics. In a preliminary experimental evaluation, a hemiparetic stroke patient performed a 10 m to-and-fro straight line walking task with and without assist wear on the affected side. We found that the assist wear enabled natural movement, increasing step length and decreasing muscular activity during straight line walking. We demonstrated that the assistance effect could be adjusted by controlling the on-off time of the PVC gel soft actuators. The results show the effectiveness of the proposed system and suggest the feasibility of PVC gel soft actuators for developing practical soft wearable assistive devices, informing the development of future wearable robots and the other soft actuator technologies for human movement assistance and rehabilitation.

可塑化PVCゲルアクチュエータ製造のための印刷技術を適用したゲル薄膜形成自動化技術の開発

Plasticized poly vinyl chloride (PVC) gel which has a large deformation by applying a voltage and high driving stability in the atmosphere is considered as a promising material for a soft actuator. To fabricate a more flexible and high performance multilayered PVC gel actuator, in this study, we attempt to develop automation technology for fabricating thin film PVC gel used in multilayered PVC gel actuator based on digital 3D printing technology. We proposed automation system and examined to adjust amount of coating by control the condition of coating. Under the condition of 0.06 mg/shot of the amount of coated gel per shot, the average dot diameter of the point coated gel was about 0. 86 mm and the height was about 8 μm. It was expected that a gel thin film of about several μm can be automatically produced in an arbitrary shape by using the proposed system.

Design and prototyping of a novel lightweight walking assist wear using PVC gel soft actuators

Innovative technologies are needed to support the daily activities of elderly people and to lighten the heavy burden of nursing in the aging society. And the technology of soft actuators should be one of the key issues for developing such technologies. We have developed a soft actuator using the plasticized polyvinyl chloride (PVC) gel which has many positive characteristics, such as being soft and lightweight, having a stable actuation in the air with a high output, a notable response rate, a low power consumption and no noise. In this study, we applied the PVC gel soft actuators to develop a novel lightweight walking assist wear for a daily life support of the elderly people. We used the contraction and expansion movement and generation force of the actuators to provide the assistance. And we used some force sensors integrated in the insoles to detect the gait changes during walking. A prototype was designed, fabricated and the characteristics were evaluated in this paper. The prototype has a mass of about 0.6kg, with an output force about 94N (corresponding to torque of over 10% of the nominal biological moment at the hip during unloaded walking), a power consumption of about 1.6W. The proposed assist wear has the advantages of a simple structure, light weight, high flexibility and easy to put on and take off which indicate the feasibility to use for a daily life walking assistance.

PVC gel based artificial muscles: Characterizations and actuation modular constructions

Polymer materials based artificial muscles have the properties of being soft, lightweight, and flexible which are similar to the nature muscular actuators. In our previous study, we have developed a contraction type artificial muscle based on plasticized poly vinyl chloride (PVC) gel and meshed electrodes. And we have improved the characteristics to make it close to the level of natural muscle. It has many positive characteristics, such as stable actuation in the air, high output, notable response rate, and low power consumption. So a wide application is expected. However, for practical applications, it is necessary to consider some specific criteria, such as performance criteria and structural criteria. In this study, we introduced the most updated properties of PVC gel artificial muscles and proposed three types of mechanical actuation modular constructions for making the PVC gel artificial muscle as a robust actuation device for robotics and mechatronics. And we tested a prototype to examine the effectiveness of the proposed modules. Finally, an analytical model for the static characteristics of PVC gel artificial muscles at different applied voltages was derived and showed good agreement with experimental results measured by a prototype of modules.