Functional carbon materials are the key to a clean, safe, and sustainable working environment and advanced energy-related devices because they can be reused, recycled, and repurposed. However, effort is necessary to make them ideal candidates for such applications. In this study, we introduce a novel approach by designing covalent-organic frameworks (COFs) and metal-organic frameworks (MOFs) with contrasting electrical and electrochemical properties, aiming to achieve highly desirable electrochemical soft actuators. A careful structural investigation is carried out to determine the structure–property relationship, while the fascinating properties of them are validated by real-field demonstrations. The proposed functional carbon materials exhibit exceptional actuation properties, thereby representing a significant advancement for complex robotic interactions.
In the field of energy harvesting and sensing technologies, triboelectric nanogenerators (TENGs) have emerged as a promising platform for self-powered sensors. However, user convenience is often overlooked during the material and design selection process. User-friendliness relies not only on material flexibility but also on the sensitivity of the force-to-signal relationship in TENG applications. This study aims to address this gap by tailoring material properties to enhance user experience specifically. We investigated the electrical and mechanical properties of various filler materials, utilizing styrene-ethylene-butylene-styrene (SEBS) as a stretchable polymer base. The resulting self-standing membranes were evaluated for comfort, durability, and adaptability, while maintaining functional effectiveness under low external force. These findings lay the groundwork for designing user-centric, self-powered sensing systems based on TENGs.
Carbon materials are the key to a clean, safe, and sustainable working environment and advanced energy-related devices because they can be reused, recycled, and repurposed. However, effort is necessary to make them ideal candidates for such applications. Here, we design unprecedented carbon materials in the form of covalent-organic and metal-organic frameworks having antagonistic properties to achieve the desirable electro-active artificial muscles. A careful structural investigation is carried out to determine the structure–property relationship, while the fascinating properties of them are validated by real-field demonstrations. The proposed carbon materials show significantly high blocking force, that is ≈30 times of its weight and high bending deflection with fast rising.
Metal organic frameworks (MOFs) are a new generation of functional material which amalgamate favorable properties of both organic materials and inorganic useful metals. Owing to this harmony of traits, these MOFs have been employed as active catalysts, gas separators and storage materials. A new avenue recently established is their utilization as active electrode material for EAP actuators.
This study introduces a technique to tailor the desirable properties of MOF derivatives. It is found herein for a novel Co-MOF material, that by tuning synthesis parameters the pore size and hence active surface area of the as-synthesized Co-MOF derivatives can be enhanced. These novel Co-MOF derivatives (CoPCS) show drastically improved electrochemical properties and far superior actuation in terms of robustness and durability.
a low temperature fast synthetic strategy is adopted for directly growing MnBTC MOFs on conductive Ti3C2Tx MXene surface to achieve a smart hybrid conductive and hierarchical porous structure Ti3C2Tx MnBTC materials. Then, a flexible actuator membrane is fabricated by sandwich layer by layer structure with PEDOT:PSS embedding mobile ionic liquid (EMIM-BF4) and used for electroactive artificial muscles. The newly developed actuator demonstrates excellent actuation performance including highly bending displacement (12.5 mm) and ultrafast response time (0.77 s) under a low driving voltage (0.5V), along with wide frequency response (0.1 to 10 Hz) and excellent long-term durability (12 hr, 98% retention).
A pre‐designed functional π‐conjugated nanoporous covalent organic frameworks (COFs) are suggested to develop a high‐performance electrode for electroactive ionic soft actuators. In-depth structural characterization confirm the structural integrity of the developed active materials. Nanoporous structural configuration of COFs acted as nanoreactors for boosting the transportation and accommodation of oppositely charged ions in presence of available electrolytes during the switching of an alternating current input signal. As a results, the soft electroactive actuators show fast rise times, short phase delays, strong blocking force, high bending displacement, and ultralong durability.
A triboelectric energy harvester with a long-lasting and steady output was developed by using an escapement mechanism to induce a much larger torque after storing the irregular input motion as elastic energy in a spiral torsion spring. The escapement mechanism-based triboelectric nanogenerator (EM-TENG) consists of the spiral torsion spring, escapement part, and a torsional resonator for regular operation and frequency up-conversion using freestanding mode interdigitated electrodes. Under only 5 s of input motion, the EM-TENG produces long-lasting and steady output power for 110 s by using the escapement mechanism.
In spite of the simple fabrication process, Ionic electroactive polymers (iEAP) work based on a very complex actuation mechanism that is originated in the movement of unequally sized ions through the ionic channels inside the polymer membrane. Such a sophisticated mechanism leads to nonlinear behavior of iEAPs while subjected to electric stimulation and makes their response unpredictable. Here we propose a real-time measurement technique for tracing the movement of ions inside the polymer membrane to better estimate the behavior of the iEAPs during actuation. To do so, a highly flexible and porous electrode is needed to be incorporated into the polymer membrane thus it neither blocks the ions’ path nor restricts the mechanical deformation. Using such an electrode one can measure the internal electrical potential of the membrane, during actuation, to monitor the potential alteration caused by the ions’ migration inside the membrane.
Triboelectric nanogenerators (TENGs) can be utilized as power sources of wearable devices because of flexibility, light weight and cost effective devices. However, materials utilized in the wearable devices should be carefully selected to avoid side effects to the human body. In this work, we developed a chitosan-diatom (CD) composite film for triboelectric nanogenerators(TENGs) and fabricated a skin-attachable motion sensor. The CD film was composed of the chitosan and diatom silica. All of materials are biomaterials which cannot cause side effects. The biocompatible diatom silica embedded in the chitosan film enhanced the positive charge density of the chitosan film. The CD film was assembled with the fluorinated ethylene propylene (FEP) film for a contact and separation TENG. The maximum instantaneous power density was 468 mW/m2, which was 3.5 times higher than the chitosan film. Furthermore, the skin-attachable motion sensor was developed base on the CD TENG. We believe this work can provide the simple and safe way to increase the performance of biocompatible TENGs for wearable devices.
Electroactive artificial muscles has drawn special attention for potential engineering applications, such as biomedical active devices, haptic-feedback systems, wearable soft electronics, and soft micro-robotics. However in the field of bioinspired soft robotics, to accomplish sophisticated tasks as human fingers, electroactive artificial muscles are under development. Because, most of the exiting soft actuators show lack of high bending displacements with irregular response characteristics under low input voltages due to instabilities of active electrode materials under operation. This situation necessitates for the development of totally brand new functional electrode materials with enormous stability under prolonged electro-chemical exposures. The developed electrode materials based on pre-designed functional covalent organic frameworks and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) show promising actuation characteristics under low electric stimuli towards real-field soft robotics. The proposed artificial muscles can readily be operated on fragile display to make a soft touch similar to real human finger and can successfully accomplishes precise sophisticated tasks such as controlling personal folders and swiping pages of online books, and playing music apps.
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