Journal articles on the topic 'Self-Healing, Flexible electronics,soft robotics'
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Su, Jheng-Wun, Xiang Tao, Heng Deng, Cheng Zhang, Shan Jiang, Yuyi Lin, and Jian Lin. "4D printing of a self-morphing polymer driven by a swellable guest medium." Soft Matter 14, no. 5 (2018): 765–72. http://dx.doi.org/10.1039/c7sm01796k.
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There is a significant need of advanced materials that can be fabricated into functional devices with defined three-dimensional (3D) structures for application in tissue engineering, flexible electronics, and soft robotics.
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Raman, Srinivasan, and Ravi Sankar Arunagirinathan. "Silver Nanowires in Stretchable Resistive Strain Sensors." Nanomaterials 12, no. 11 (June 6, 2022): 1932. http://dx.doi.org/10.3390/nano12111932.
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Silver nanowires (AgNWs), having excellent electrical conductivity, transparency, and flexibility in polymer composites, are reliable options for developing various sensors. As transparent conductive electrodes (TCEs), AgNWs are applied in optoelectronics, organic electronics, energy devices, and flexible electronics. In recent times, research groups across the globe have been concentrating on developing flexible and stretchable strain sensors with a specific focus on material combinations, fabrication methods, and performance characteristics. Such sensors are gaining attention in human motion monitoring, wearable electronics, advanced healthcare, human-machine interfaces, soft robotics, etc. AgNWs, as a conducting network, enhance the sensing characteristics of stretchable strain-sensing polymer composites. This review article presents the recent developments in resistive stretchable strain sensors with AgNWs as a single or additional filler material in substrates such as polydimethylsiloxane (PDMS), thermoplastic polyurethane (TPU), polyurethane (PU), and other substrates. The focus is on the material combinations, fabrication methods, working principles, specific applications, and performance metrics such as sensitivity, stretchability, durability, transparency, hysteresis, linearity, and additional features, including self-healing multifunctional capabilities.
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Lian, Jia-Jin, Wen-Tao Guo, and Qi-Jun Sun. "Emerging Functional Polymer Composites for Tactile Sensing." Materials 16, no. 12 (June 11, 2023): 4310. http://dx.doi.org/10.3390/ma16124310.
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In recent years, extensive research has been conducted on the development of high-performance flexible tactile sensors, pursuing the next generation of highly intelligent electronics with diverse potential applications in self-powered wearable sensors, human–machine interactions, electronic skin, and soft robotics. Among the most promising materials that have emerged in this context are functional polymer composites (FPCs), which exhibit exceptional mechanical and electrical properties, enabling them to be excellent candidates for tactile sensors. Herein, this review provides a comprehensive overview of recent advances in FPCs-based tactile sensors, including the fundamental principle, the necessary property parameter, the unique device structure, and the fabrication process of different types of tactile sensors. Examples of FPCs are elaborated with a focus on miniaturization, self-healing, self-cleaning, integration, biodegradation, and neural control. Furthermore, the applications of FPC-based tactile sensors in tactile perception, human–machine interaction, and healthcare are further described. Finally, the existing limitations and technical challenges for FPCs-based tactile sensors are briefly discussed, offering potential avenues for the development of electronic products.
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Heidarian, Pejman, and Abbas Z. Kouzani. "Starch-g-Acrylic Acid/Magnetic Nanochitin Self-Healing Ferrogels as Flexible Soft Strain Sensors." Sensors 23, no. 3 (January 19, 2023): 1138. http://dx.doi.org/10.3390/s23031138.
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Mechanically robust ferrogels with high self-healing ability might change the design of soft materials used in strain sensing. Herein, a robust, stretchable, magneto-responsive, notch insensitive, ionic conductive nanochitin ferrogel was fabricated with both autonomous self-healing and needed resilience for strain sensing application without the need for additional irreversible static chemical crosslinks. For this purpose, ferric (III) chloride hexahydrate and ferrous (II) chloride as the iron source were initially co-precipitated to create magnetic nanochitin and the co-precipitation was confirmed by FTIR and microscopic images. After that, the ferrogels were fabricated by graft copolymerisation of acrylic acid-g-starch with a monomer/starch weight ratio of 1.5. Ammonium persulfate and magnetic nanochitin were employed as the initiator and crosslinking/nano-reinforcing agents, respectively. The ensuing magnetic nanochitin ferrogel provided not only the ability to measure strain in real-time under external magnetic actuation but also the ability to heal itself without any external stimulus. The ferrogel may also be used as a stylus for a touch-screen device. Based on our findings, our research has promising implications for the rational design of multifunctional hydrogels, which might be used in applications such as flexible and soft strain sensors, health monitoring, and soft robotics.
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Ankit, Naveen Tiwari, Fanny Ho, Febby Krisnadi, Mohit Rameshchandra Kulkarni, Linh Lan Nguyen, Soo Jin Adrian Koh, and Nripan Mathews. "High-k, Ultrastretchable Self-Enclosed Ionic Liquid-Elastomer Composites for Soft Robotics and Flexible Electronics." ACS Applied Materials & Interfaces 12, no. 33 (July 20, 2020): 37561–70. http://dx.doi.org/10.1021/acsami.0c08754.
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Nyabadza, Anesu, Mercedes Vázquez, Shirley Coyle, Brian Fitzpatrick, and Dermot Brabazon. "Review of Materials and Fabrication Methods for Flexible Nano and Micro-Scale Physical and Chemical Property Sensors." Applied Sciences 11, no. 18 (September 15, 2021): 8563. http://dx.doi.org/10.3390/app11188563.
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The use of flexible sensors has tripled over the last decade due to the increased demand in various fields including health monitoring, food packaging, electronic skins and soft robotics. Flexible sensors have the ability to be bent and stretched during use and can still maintain their electrical and mechanical properties. This gives them an advantage over rigid sensors that lose their sensitivity when subject to bending. Advancements in 3D printing have enabled the development of tailored flexible sensors. Various additive manufacturing methods are being used to develop these sensors including inkjet printing, aerosol jet printing, fused deposition modelling, direct ink writing, selective laser melting and others. Hydrogels have gained much attention in the literature due to their self-healing and shape transforming. Self-healing enables the sensor to recover from damages such as cracks and cuts incurred during use, and this enables the sensor to have a longer operating life and stability. Various polymers are used as substrates on which the sensing material is placed. Polymers including polydimethylsiloxane, Poly(N-isopropylacrylamide) and polyvinyl acetate are extensively used in flexible sensors. The most widely used nanomaterials in flexible sensors are carbon and silver due to their excellent electrical properties. This review gives an overview of various types of flexible sensors (including temperature, pressure and chemical sensors), paying particular attention to the application areas and the corresponding characteristics/properties of interest required for such. Current advances/trends in the field including 3D printing, novel nanomaterials and responsive polymers, and self-healable sensors and wearables will also be discussed in more detail.
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Huang, Changjin, David Quinn, Subra Suresh, and K. Jimmy Hsia. "Controlled molecular self-assembly of complex three-dimensional structures in soft materials." Proceedings of the National Academy of Sciences 115, no. 1 (December 18, 2017): 70–74. http://dx.doi.org/10.1073/pnas.1717912115.
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Many applications in tissue engineering, flexible electronics, and soft robotics call for approaches that are capable of producing complex 3D architectures in soft materials. Here we present a method using molecular self-assembly to generate hydrogel-based 3D architectures that resembles the appealing features of the bottom-up process in morphogenesis of living tissues. Our strategy effectively utilizes the three essential components dictating living tissue morphogenesis to produce complex 3D architectures: modulation of local chemistry, material transport, and mechanics, which can be engineered by controlling the local distribution of polymerization inhibitor (i.e., oxygen), diffusion of monomers/cross-linkers through the porous structures of cross-linked polymer network, and mechanical constraints, respectively. We show that oxygen plays a role in hydrogel polymerization which is mechanistically similar to the role of growth factors in tissue growth, and the continued growth of hydrogel enabled by diffusion of monomers/cross-linkers into the porous hydrogel similar to the mechanisms of tissue growth enabled by material transport. The capability and versatility of our strategy are demonstrated through biomimetics of tissue morphogenesis for both plants and animals, and its application to generate other complex 3D architectures. Our technique opens avenues to studying many growth phenomena found in nature and generating complex 3D structures to benefit diverse applications.
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Gong, Yanting, Yi-Zhou Zhang, Shiqiang Fang, Chen Liu, Jian Niu, Guanjun Li, Fang Li, Xiangchun Li, Tao Cheng, and Wen-Yong Lai. "Artificial intelligent optoelectronic skin with anisotropic electrical and optical responses for multi-dimensional sensing." Applied Physics Reviews 9, no. 2 (June 2022): 021403. http://dx.doi.org/10.1063/5.0083278.
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Artificial intelligent skins hold the potential to revolutionize artificial intelligence, health monitoring, soft robotics, biomedicine, flexible, and wearable electronics. Present artificial skins can be characterized into electronic skins ( e-skins) that convert external stimuli into electrical signals and photonic skins ( p-skins) that convert deformations into intuitive optical feedback. Merging both electronic and photonic functions in a single skin is highly desirable, but challenging and remains yet unexplored. We report herein a brand-new type of artificial intelligent skin, an optoelectronic skin ( o-skin), which combines the advantages of both e-skins and p-skins in a single skin device based on one-dimensional photonic crystal-based hydrogels. Taking advantage of its anisotropic characteristics, the resulting o-skin can easily distinguish vector stimuli such as stress type and movement direction to meet the needs of multi-dimensional perception. Furthermore, the o-skin also demonstrates advanced functions such as full-color displays and intelligent response to the environment in the form of self-adaptive camouflage. This work represents a substantial advance in using the molecular engineering strategy to achieve artificial intelligent skins with multiple anisotropic responses that can be integrated on the skin of a soft body to endow superior functions, just like the natural organisms that inspire us.
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Ito, Takatoshi, Eri Fukuchi, Kenta Tanaka, Yuki Nishiyama, Naoto Watanabe, and Ohmi Fuchiwaki. "Vision Feedback Control for the Automation of the Pick-and-Place of a Capillary Force Gripper." Micromachines 13, no. 8 (August 7, 2022): 1270. http://dx.doi.org/10.3390/mi13081270.
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In this paper, we describe a newly developed vision feedback method for improving the placement accuracy and success rate of a single nozzle capillary force gripper. The capillary force gripper was developed for the pick-and-place of mm-sized objects. The gripper picks up an object by contacting the top surface of the object with a droplet formed on its nozzle and places the object by contacting the bottom surface of the object with a droplet previously applied to the place surface. To improve the placement accuracy, we developed a vision feedback system combined with two cameras. First, a side camera was installed to capture images of the object and nozzle from the side. Second, from the captured images, the contour of the pre-applied droplet for placement and the contour of the object picked up by the nozzle were detected. Lastly, from the detected contours, the distance between the top surface of the droplet for object release and the bottom surface of the object was measured to determine the appropriate amount of nozzle descent. Through the experiments, we verified that the size matching effect worked reasonably well; the average placement error minimizes when the size of the cross-section of the objects is closer to that of the nozzle. We attributed this result to the self-alignment effect. We also confirmed that we could control the attitude of the object when we matched the shape of the nozzle to that of the sample. These results support the feasibility of the developed vision feedback system, which uses the capillary force gripper for heterogeneous and complex-shaped micro-objects in flexible electronics, micro-electro-mechanical systems (MEMS), soft robotics, soft matter, and biomedical fields.
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Deriabin, Konstantin V., Sofia S. Filippova, and Regina M. Islamova. "Self-Healing Silicone Materials: Looking Back and Moving Forward." Biomimetics 8, no. 3 (July 3, 2023): 286. http://dx.doi.org/10.3390/biomimetics8030286.
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This review is dedicated to self-healing silicone materials, which can partially or entirely restore their original characteristics after mechanical or electrical damage is caused to them, such as formed (micro)cracks, scratches, and cuts. The concept of self-healing materials originated from biomaterials (living tissues) capable of self-healing and regeneration of their functions (plants, human skin and bones, etc.). Silicones are ones of the most promising polymer matrixes to create self-healing materials. Self-healing silicones allow an increase of the service life and durability of materials and devices based on them. In this review, we provide a critical analysis of the current existing types of self-healing silicone materials and their functional properties, which can be used in biomedicine, optoelectronics, nanotechnology, additive manufacturing, soft robotics, skin-inspired electronics, protection of surfaces, etc.
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Joshi, Gaurav. "Innovations in Soft Robotics: Design and Control of Flexible Mechatronic Systems." Mathematical Statistician and Engineering Applications 70, no. 1 (January 31, 2021): 479–85. http://dx.doi.org/10.17762/msea.v70i1.2500.
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Soft robotics, an emerging field at the intersection of robotics and materials science, has gained significant attention in recent years due to its potential for creating highly adaptable and versatile robotic systems. Unlike traditional rigid robots, soft robotics focuses on designing and controlling flexible mechatronic systems that can mimic the natural movements and interactions of living organisms. This paper presents an overview of the recent innovations in soft robotics, specifically focusing on the design and control aspects of flexible mechatronic systems.The design of soft robots involves the integration of advanced materials and mechanisms that enable compliance and flexibility in the robot's body structure. Various materials, such as elastomers, hydrogels, and shape-memory polymers, have been explored for constructing soft robotic components that can deform and recover their shape. These materials exhibit unique properties, such as stretchability, elasticity, and self-healing capabilities, allowing soft robots to adapt to complex and dynamic environments. Additionally, the design of soft robotic systems often incorporates pneumatic or hydraulic actuation mechanisms to achieve locomotion and manipulation.In conclusion, this paper provides an overview of the recent innovations in soft robotics, focusing on the design and control of flexible mechatronic systems. Soft robots have the potential to revolutionize various fields by providing adaptive and versatile robotic systems. The integration of advanced materials, novel actuation mechanisms, and innovative control strategies has paved the way for the development of soft robots with remarkable capabilities. However, further research is needed to address the existing challenges and unlock the full potential of soft robotics in practical applications.
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Markvicka, Eric J., Michael D. Bartlett, Xiaonan Huang, and Carmel Majidi. "An autonomously electrically self-healing liquid metal–elastomer composite for robust soft-matter robotics and electronics." Nature Materials 17, no. 7 (May 21, 2018): 618–24. http://dx.doi.org/10.1038/s41563-018-0084-7.
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Cerdan, Kenneth, Carlos Moya, Peter Van Puyvelde, Gilles Bruylants, and Joost Brancart. "Magnetic Self-Healing Composites: Synthesis and Applications." Molecules 27, no. 12 (June 13, 2022): 3796. http://dx.doi.org/10.3390/molecules27123796.
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Magnetic composites and self-healing materials have been drawing much attention in their respective fields of application. Magnetic fillers enable changes in the material properties of objects, in the shapes and structures of objects, and ultimately in the motion and actuation of objects in response to the application of an external field. Self-healing materials possess the ability to repair incurred damage and consequently recover the functional properties during healing. The combination of these two unique features results in important advances in both fields. First, the self-healing ability enables the recovery of the magnetic properties of magnetic composites and structures to extend their service lifetimes in applications such as robotics and biomedicine. Second, magnetic (nano)particles offer many opportunities to improve the healing performance of the resulting self-healing magnetic composites. Magnetic fillers are used for the remote activation of thermal healing through inductive heating and for the closure of large damage by applying an alternating or constant external magnetic field, respectively. Furthermore, hard magnetic particles can be used to permanently magnetize self-healing composites to autonomously re-join severed parts. This paper reviews the synthesis, processing and manufacturing of magnetic self-healing composites for applications in health, robotic actuation, flexible electronics, and many more.
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Ford, Michael J., Yunsik Ohm, Keene Chin, and Carmel Majidi. "Composites of functional polymers: Toward physical intelligence using flexible and soft materials." Journal of Materials Research 37, no. 1 (October 19, 2021): 2–24. http://dx.doi.org/10.1557/s43578-021-00381-5.
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AbstractMaterials that can assist with perception and responsivity of an engineered machine are said to promote physical intelligence. Physical intelligence may be important for flexible and soft materials that will be used in applications like soft robotics, wearable computers, and healthcare. These applications require stimuli responsivity, sensing, and actuation that allow a machine to perceive and react to its environment. The development of materials that exhibit some form of physical intelligence has relied on functional polymers and composites that contain these polymers. This review will focus on composites of functional polymers that display physical intelligence by assisting with perception, responsivity, or by off-loading computation. Composites of liquid crystal elastomers, shape-memory polymers, hydrogels, self-healing materials, and transient materials and their functionalities are examined with a viewpoint that considers physical intelligence. Graphic Abstract
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Song, Lijuan, Zheng Zhang, Xiaochen Xun, Liangxu Xu, Fangfang Gao, Xuan Zhao, Zhuo Kang, Qingliang Liao, and Yue Zhang. "Fully Organic Self-Powered Electronic Skin with Multifunctional and Highly Robust Sensing Capability." Research 2021 (February 20, 2021): 1–10. http://dx.doi.org/10.34133/2021/9801832.
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Electronic skin (e-skin) with skin-like flexibility and tactile sensation will promote the great advancements in the fields of wearable equipment. Thus, the multifunction and high robustness are two important requirements for sensing capability of the e-skin. Here, a fully organic self-powered e-skin (FOSE-skin) based on the triboelectric nanogenerator (TENG) is developed. FOSE-skin based on TENG can be fully self-healed within 10 hours after being sheared by employing the self-healing polymer as a triboelectric layer and ionic liquid with the temperature sensitivity as an electrode. FOSE-skin based on TENG has the multifunctional and highly robust sensing capability and can sense the pressure and temperature simultaneously. The sensing capability of the FOSE-skin based on TENG can be highly robust with no changes after self-healing. FOSE-skin based on TENG can be employed to detect the arm swing, the temperature change of flowing water, and the motion trajectory. This work provides a new idea for solving the issues of monofunctional and low robust sensing capability for FOSE-skin based on TENG, which can further promote the application of wearable electronics in soft robotics and bionic prosthetics.
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Han, Koohee. "Electric and Magnetic Field-Driven Dynamic Structuring for Smart Functional Devices." Micromachines 14, no. 3 (March 16, 2023): 661. http://dx.doi.org/10.3390/mi14030661.
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The field of soft matter is rapidly growing and pushing the limits of conventional materials science and engineering. Soft matter refers to materials that are easily deformed by thermal fluctuations and external forces, allowing for better adaptation and interaction with the environment. This has opened up opportunities for applications such as stretchable electronics, soft robotics, and microfluidics. In particular, soft matter plays a crucial role in microfluidics, where viscous forces at the microscale pose a challenge to controlling dynamic material behavior and operating functional devices. Field-driven active colloidal systems are a promising model system for building smart functional devices, where dispersed colloidal particles can be activated and controlled by external fields such as magnetic and electric fields. This review focuses on building smart functional devices from field-driven collective patterns, specifically the dynamic structuring of hierarchically ordered structures. These structures self-organize from colloidal building blocks and exhibit reconfigurable collective patterns that can implement smart functions such as shape shifting and self-healing. The review clarifies the basic mechanisms of field-driven particle dynamic behaviors and how particle–particle interactions determine the collective patterns of dynamic structures. Finally, the review concludes by highlighting representative application areas and future directions.
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Selleri, Giacomo, Francesco Mongioì, Emanuele Maccaferri, Riccardo D’Anniballe, Laura Mazzocchetti, Raffaella Carloni, Davide Fabiani, Andrea Zucchelli, and Tommaso Maria Brugo. "Self-Sensing Soft Skin Based on Piezoelectric Nanofibers." Polymers 15, no. 2 (January 5, 2023): 280. http://dx.doi.org/10.3390/polym15020280.
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The development of electronic skins and wearable devices is rapidly growing due to their broad application fields, such as for biomedical, health monitoring, or robotic purposes. In particular, tactile sensors based on piezoelectric polymers, which feature self-powering capability, have been widely used thanks to their flexibility and light weight. Among these, poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) presents enhanced piezoelectric properties, especially if manufactured in a nanofiber shape. In this work, the enhanced piezoelectric performances of PVDF-TrFE nanofibers were exploited to manufacture a flexible sensor which can be used for wearable applications or e-skin. The piezoelectric signal was collected by carbon black (CB)-based electrodes, which were added to the active layer in a sandwich-like structure. The sensor was electromechanically characterized in a frequency range between 0.25 Hz and 20 Hz—which is consistent with human activities (i.e., gait cycle or accidental bumps)—showing a sensitivity of up to 4 mV/N. The parameters of the signal acquisition circuit were tuned to enable the sensor to work at the required frequency. The proposed electrical model of the nanofibrous piezoelectric sensor was validated by the experimental results. The sensitivity of the sensor remained above 77.5% of its original value after 106 cycles of fatigue testing with a 1 kN compressive force.
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Yu, You, Joanna Nassar, Changhao Xu, Jihong Min, Yiran Yang, Adam Dai, Rohan Doshi, et al. "Biofuel-powered soft electronic skin with multiplexed and wireless sensing for human-machine interfaces." Science Robotics 5, no. 41 (April 22, 2020): eaaz7946. http://dx.doi.org/10.1126/scirobotics.aaz7946.
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Existing electronic skin (e-skin) sensing platforms are equipped to monitor physical parameters using power from batteries or near-field communication. For e-skins to be applied in the next generation of robotics and medical devices, they must operate wirelessly and be self-powered. However, despite recent efforts to harvest energy from the human body, self-powered e-skin with the ability to perform biosensing with Bluetooth communication are limited because of the lack of a continuous energy source and limited power efficiency. Here, we report a flexible and fully perspiration-powered integrated electronic skin (PPES) for multiplexed metabolic sensing in situ. The battery-free e-skin contains multimodal sensors and highly efficient lactate biofuel cells that use a unique integration of zero- to three-dimensional nanomaterials to achieve high power intensity and long-term stability. The PPES delivered a record-breaking power density of 3.5 milliwatt·centimeter−2 for biofuel cells in untreated human body fluids (human sweat) and displayed a very stable performance during a 60-hour continuous operation. It selectively monitored key metabolic analytes (e.g., urea, NH4+, glucose, and pH) and the skin temperature during prolonged physical activities and wirelessly transmitted the data to the user interface using Bluetooth. The PPES was also able to monitor muscle contraction and work as a human-machine interface for human-prosthesis walking.
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Jin, Subin, Yewon Kim, Donghee Son, and Mikyung Shin. "Tissue Adhesive, Conductive, and Injectable Cellulose Hydrogel Ink for On-Skin Direct Writing of Electronics." Gels 8, no. 6 (May 30, 2022): 336. http://dx.doi.org/10.3390/gels8060336.
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Flexible and soft bioelectronics used on skin tissue have attracted attention for the monitoring of human health. In addition to typical metal-based rigid electronics, soft polymeric materials, particularly conductive hydrogels, have been actively developed to fabricate biocompatible electrical circuits with a mechanical modulus similar to biological tissues. Although such conductive hydrogels can be wearable or implantable in vivo without any tissue damage, there are still challenges to directly writing complex circuits on the skin due to its low tissue adhesion and heterogeneous mechanical properties. Herein, we report cellulose-based conductive hydrogel inks exhibiting strong tissue adhesion and injectability for further on-skin direct printing. The hydrogels consisting of carboxymethyl cellulose, tannic acid, and metal ions (e.g., HAuCl4) were crosslinked via multiple hydrogen bonds between the cellulose backbone and tannic acid and metal-phenol coordinate network. Owing to this reversible non-covalent crosslinking, the hydrogels showed self-healing properties and reversible conductivity under cyclic strain from 0 to 400%, as well as printability on the skin tissue. In particular, the on-skin electronic circuit printed using the hydrogel ink maintained a continuous electrical flow under skin deformation, such as bending and twisting, and at high relative humidity of 90%. These printable and conductive hydrogels are promising for implementing structurally complicated bioelectronics and wearable textiles.
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Shinde, Vinita V., Yuyang Wang, Md Fahim Salek, Maria L. Auad, Lauren E. Beckingham, and Bryan S. Beckingham. "Material Design for Enhancing Properties of 3D Printed Polymer Composites for Target Applications." Technologies 10, no. 2 (March 23, 2022): 45. http://dx.doi.org/10.3390/technologies10020045.
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Polymer composites are becoming an important class of materials for a diversified range of industrial applications due to their unique characteristics and natural and synthetic reinforcements. Traditional methods of polymer composite fabrication require machining, manual labor, and increased costs. Therefore, 3D printing technologies have come to the forefront of scientific, industrial, and public attention for customized manufacturing of composite parts having a high degree of control over design, processing parameters, and time. However, poor interfacial adhesion between 3D printed layers can lead to material failure, and therefore, researchers are trying to improve material functionality and extend material lifetime with the addition of reinforcements and self-healing capability. This review provides insights on different materials used for 3D printing of polymer composites to enhance mechanical properties and improve service life of polymer materials. Moreover, 3D printing of flexible energy-storage devices (FESD), including batteries, supercapacitors, and soft robotics using soft materials (polymers), is discussed as well as the application of 3D printing as a platform for bioengineering and earth science applications by using a variety of polymer materials, all of which have great potential for improving future conditions for humanity and planet Earth.
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Xie, Mengying, Mingzhu Zhu, Zhaoshu Yang, Shima Okada, and Sadao Kawamura. "Flexible self-powered multifunctional sensor for stiffness-tunable soft robotic gripper by multimaterial 3D printing." Nano Energy 79 (January 2021): 105438. http://dx.doi.org/10.1016/j.nanoen.2020.105438.
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Singh, Rahul Kumar, Sun Woh Lye, and Jianmin Miao. "PVDF Nanofiber Sensor for Vibration Measurement in a String." Sensors 19, no. 17 (August 29, 2019): 3739. http://dx.doi.org/10.3390/s19173739.
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Flexible, self-powered and miniaturized sensors are extensively used in the areas of sports, soft robotics, health care and communication devices. Measurement of vibration is important for determining the mechanical properties of a structure, specifically the string tension in strings. In this work, a flexible, lightweight and self-powered sensor is developed and attached to a string to measure vibrations characteristics in strings. Electrospun poly(vinylidene) fluoride (PVDF) nanofibers are deposited on a flexible liquid crystal polymer (LCP) substrate for the development of the sensor. The electrospinning process is optimized for different needle sizes (0.34–0.84 mm) and flow rates (0.6–3 mL/h). The characterization of the sensor is done in a cantilever configuration and the test results indicate the sensor’s capability to measure the frequency and strain in the required range. The comparison of the results from the developed PVDF sensor and a commercial Laser Displacement Sensor (LDS) showed good resemblance (±0.2%) and a linear voltage profile (0.2 mV/με). The sensor, upon attachment to a racket string, is able to measure single impacts and sinusoidal vibrations. The repeatability of the results on the measurement of vibrations produced by an impact hammer and a mini shaker demonstrate an exciting new application for piezoelectric sensors.
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Prechtl, J., J. Kunze, G. Moretti, D. Bruch, S. Seelecke, and G. Rizzello. "Modeling and experimental validation of thin, tightly rolled dielectric elastomer actuators." Smart Materials and Structures 31, no. 1 (November 19, 2021): 015008. http://dx.doi.org/10.1088/1361-665x/ac34be.
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Abstract Due to their large deformation, high energy density, and high compliance, dielectric elastomer actuators (DEAs) have found a number of applications in several areas of mechatronics and robotics. Among the many types of DEAs proposed in the literature, rolled DEAs (RDEAs) represent one of the most popular configurations. RDEAs can be effectively used as compact muscle-like actuators for soft robots, since they allow eliminating the need for external motors or compressors while providing at the same time a flexible and lightweight structure with self-sensing capabilities. To effectively design and control complex RDEA-driven systems and robots, accurate and numerically efficient mathematical models need to be developed. In this work, we propose a novel lumped-parameter model for silicone-based, thin and tightly rolled RDEAs. The model is grounded on a free-energy approach, and permits to describe the electro-mechanically coupled response of the transducer with a set of nonlinear ordinary differential equations. After deriving the constitutive relationships, the model is validated by means of an extensive experimental campaign, conducted on three RDEA specimens having different geometries. It is shown how the developed model permits to accurately predict the effects of several parameters (external load, applied voltage, actuator geometry) on the RDEA electro-mechanical response, while maintaining an overall simple mathematical structure.
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Kawaji, Shigeyasu, and Tetsuo Sawaragi. "Special Issue on Intelligent Control in Coming New Generation." Journal of Robotics and Mechatronics 12, no. 6 (December 20, 2000): 603–4. http://dx.doi.org/10.20965/jrm.2000.p0603.
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In the early 1970s, a concept of intelligent control was proposed by Fu, and since then the advancement of control technologies as a migrate of control theory, artificial intelligence and operations research has been actively attempted. The breakthrough of this concept was to integrate a human judgment and a concept of value as well as management theory into conventional control theoretic approaches, and synthesize these as artificial intelligence. A number of unconventional control techniques have evolved, offering solutions to many difficult control problems in industry and manufacturing. Saridis proposed a general architecture for intelligent control and proposed a design principle of such a hierarchical system as the principle of Increasing Precision with Decreasing Intelligence. During the first generation of intelligent control, a number of intelligent methodologies besides the purely symbolic and logical processing of human knowledge were introduced. They are broadly called soft computing techniques that include artificial neural networks, fuzzy logic, genetic algorithm, and chaos theory. These techniques have contributed much to the advancement of intelligent control from the viewpoint of its ""intelligence"" part, but no solutions are provided from a control theoretic viewpoint, and the definition of intelligence in terms of control theory is still left questionable. To discuss this issue, we initiated a specialist's meeting on survey of intelligent control in 1997 organized under the Institute of Electrical Engineers of Japan, and discussed the current status as well as future perspectives of intelligent control. Some of the papers contributed to this special issue are results obtained in this series of meetings. During that time, the framework of intelligent control has entered the second generation. In the first stage, this framework was discussed in terms of utilized methodologies such as control theory, artificial intelligence, and operations research seeking optimal combinations of these methodologies wherein a distinction is made between the controller, the plant, and the external environment and representations as well as state concepts utilized were a priorily determined and fixed without flexibility. In contrast, the second generation intelligent control system must emphasize a biologically inspired architecture that can accommodate the flexible and dynamic capabilities of living systems including human beings. That is, it must be able to grow and develop increasing capabilities of self-control, self-awareness of representation and reasoning about self and of constructing a coherent whole out of different representations. Actually, a new branch of research on artificial life and system theory of function emergence has shifted the perspectives of intelligence from conventional reductionism to a new design principle based on the concept of ""emergence"". Thus, their approach is quite new in that they attempt to build models that bring together self-organizing mechanisms with evolutionary computation. Such a trend has forced us to reconsider the biological system and/or natural intelligence. In this special issue, we focus on the aspects of semiosis within a multigranular architecture and of emergent properties and techniques for human-machine and/or multiagent collaborative control systems in the coming new generation. These topics are mutually interrelated; the role of multivariable and multiresolutional quantization and clustering for designing intelligent controllers is essential for realizing the abilities to learn unknown multidimensional functions and/or for letting a joint system, which consists of an external environment, a human, and a machine, self-organize distinctive roles in a bottom-up and emerging fashion. This special issue includes papers on proposals of conceptual architecture, methodologies and reports from practical field studies on the hierarchical architecture of machines for realizing hierarchical collaboration and coordination among machine and human autonomies. We believe that these papers will lead to answers to the above questions. We sincerely thank the contributors and reviewers who made this special issue possible. Thanks also go to the editor-in-chief of the Journal of Robotics and Mechatronics, Prof. Makoto Kaneko (Hiroshima University), who provided the opportunity for editing this special issue.
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Yun, Guolin, Tim Cole, Yuxin Zhang, Jiahao Zheng, Shuaishuai Sun, Yiming Ou-yang, Jian Shu, et al. "Electro-mechano responsive elastomers with self-tunable conductivity and stiffness." Science Advances 9, no. 4 (January 25, 2023). http://dx.doi.org/10.1126/sciadv.adf1141.
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Materials with programmable conductivity and stiffness offer new design opportunities for next-generation engineered systems in soft robotics and electronic devices. However, existing approaches fail to harness variable electrical and mechanical properties synergistically and lack the ability to self-respond to environmental changes. We report an electro-mechano responsive Field’s metal hybrid elastomer exhibiting variable and tunable conductivity, strain sensitivity, and stiffness. By synergistically harnessing these properties, we demonstrate two applications with over an order of magnitude performance improvement compared to state-of-the-art, including a self-triggered multiaxis compliance compensator for robotic manipulators, and a resettable, highly compact, and fast current-limiting fuse with an adjustable fusing current. We envisage that the extraordinary electromechanical properties of our hybrid elastomer will bring substantial advancements in resilient robotic systems, intelligent instruments, and flexible electronics.
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Zhang, Pei, Iek Man Lei, Guangda Chen, Jingsen Lin, Xingmei Chen, Jiajun Zhang, Chengcheng Cai, Xiangyu Liang, and Ji Liu. "Integrated 3D printing of flexible electroluminescent devices and soft robots." Nature Communications 13, no. 1 (August 23, 2022). http://dx.doi.org/10.1038/s41467-022-32126-1.
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AbstractFlexible and stretchable light emitting devices are driving innovation in myriad applications, such as wearable and functional electronics, displays and soft robotics. However, the development of flexible electroluminescent devices via conventional techniques remains laborious and cost-prohibitive. Here, we report a facile and easily-accessible route for fabricating a class of flexible electroluminescent devices and soft robotics via direct ink writing-based 3D printing. 3D printable ion conducting, electroluminescent and insulating dielectric inks were developed, enabling facile and on-demand creation of flexible and stretchable electroluminescent devices with good fidelity. Robust interfacial adhesion with the multilayer electroluminescent devices endowed the 3D printed devices with attractive electroluminescent performance. Integrated our 3D printed electroluminescent devices with a soft quadrupedal robot and sensing units, an artificial camouflage that can instantly self-adapt to the environment by displaying matching color was fabricated, laying an efficient framework for the next generation soft camouflages.
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Cui, Ying, Zihao Qin, Huan Wu, Man Li, and Yongjie Hu. "Flexible thermal interface based on self-assembled boron arsenide for high-performance thermal management." Nature Communications 12, no. 1 (February 24, 2021). http://dx.doi.org/10.1038/s41467-021-21531-7.
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AbstractThermal management is the most critical technology challenge for modern electronics. Recent key materials innovation focuses on developing advanced thermal interface of electronic packaging for achieving efficient heat dissipation. Here, for the first time we report a record-high performance thermal interface beyond the current state of the art, based on self-assembled manufacturing of cubic boron arsenide (s-BAs). The s-BAs exhibits highly desirable characteristics of high thermal conductivity up to 21 W/m·K and excellent elastic compliance similar to that of soft biological tissues down to 100 kPa through the rational design of BAs microcrystals in polymer composite. In addition, the s-BAs demonstrates high flexibility and preserves the high conductivity over at least 500 bending cycles, opening up new application opportunities for flexible thermal cooling. Moreover, we demonstrated device integration with power LEDs and measured a superior cooling performance of s-BAs beyond the current state of the art, by up to 45 °C reduction in the hot spot temperature. Together, this study demonstrates scalable manufacturing of a new generation of energy-efficient and flexible thermal interface that holds great promise for advanced thermal management of future integrated circuits and emerging applications such as wearable electronics and soft robotics.
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Yu, Kunhao, Zhangzhengrong Feng, Haixu Du, Kyung Hoon Lee, Ketian Li, Yanchu Zhang, Sami F. Masri, and Qiming Wang. "Constructive adaptation of 3D-printable polymers in response to typically destructive aquatic environments." PNAS Nexus, July 29, 2022. http://dx.doi.org/10.1093/pnasnexus/pgac139.
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Abstract In response to environmental stressors, biological systems exhibit extraordinary adaptive capacity by turning destructive environmental stressors into constructive factors; however, the traditional engineering materials weaken and fail. Take the response of polymers to an aquatic environment as an example: water molecules typically compromise the mechanical properties of the polymer network in the bulk and on the interface through swelling and lubrication, respectively. Here, we report a class of 3D-printable synthetic polymers that constructively strengthen their bulk and interfacial mechanical properties in response to the aquatic environment. The mechanism relies on a water-assisted additional cross-linking reaction in the polymer matrix and on the interface. As such, the typically destructive water can constructively enhance the polymer's bulk mechanical properties such as stiffness, tensile strength, and fracture toughness by factors of 746–790%, and the interfacial bonding by a factor of 1000%. We show that the invented polymers can be used for soft robotics that self-strengthen matrix and self-heal cracks after training in water and water-healable packaging materials for flexible electronics. This work opens the door for the design of synthetic materials to imitate the constructive adaptation of biological systems in response to environmental stressors, for applications such as artificial muscles, soft robotics, and flexible electronics.
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Wang, Yangyu, Haili Qin, Zheng Li, Jing Dai, Huai-Ping Cong, and Shu-Hong Yu. "Highly compressible and environmentally adaptive conductors with high-tortuosity interconnected cellular architecture." Nature Synthesis, October 3, 2022. http://dx.doi.org/10.1038/s44160-022-00167-5.
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AbstractConductive hydrogels that are highly elastic, fatigue resistant and environmentally adaptive are promising materials in the fields of wearable electronics, bioelectronics and soft robotics. However, these materials are challenging to develop, especially for use in harsh environments including organic solvents and extreme temperatures. Here we report a simple method for the fabrication of highly compressible and fatigue-resistant conductive hydrogels with reinforced-concrete-type constituents and high-tortuosity interconnected cellular architecture through a self-assembly and two-stage in situ polymerization process. The obtained composites exhibit excellent mechanical compressibility with negligible residual strain at 50% strain for >104 cyclic loadings both in air and water. Due to the structure-favoured anisotropic response to tensile deformations coupled with elastic recovery, the hydrogel is endowed with sensing dimensions which allow the direction and velocity of movement on the sensor surface to be distinguished. In addition, by interpenetrating with an oleophilic polymer network, highly elastic and adaptive organohydrogels are developed with outstanding sensing performance in a wide variety of organic solvents and cryogenic temperatures. These materials may therefore be suitable for use in flexible and wearable devices in harsh environments.
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Tutika, Ravi, A. B. M. Tahidul Haque, and Michael D. Bartlett. "Self-healing liquid metal composite for reconfigurable and recyclable soft electronics." Communications Materials 2, no. 1 (June 14, 2021). http://dx.doi.org/10.1038/s43246-021-00169-4.
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AbstractSoft electronics and robotics are in increasing demand for diverse applications. However, soft devices typically lack rigid enclosures which can increase their susceptibility to damage and lead to failure and premature disposal. This creates a need for soft and stretchable functional materials with resilient and regenerative properties. Here we show a liquid metal-elastomer-plasticizer composite for soft electronics with robust circuitry that is self-healing, reconfigurable, and ultimately recyclable. This is achieved through an embossing technique for on-demand formation of conductive liquid metal networks which can be reprocessed to rewire or completely recycle the soft electronic composite. These skin-like electronics stretch to 1200% strain with minimal change in electrical resistance, sustain numerous damage events under load without losing electrical conductivity, and are recycled to generate new devices at the end of life. These soft composites with adaptive liquid metal microstructures can find broad use for soft electronics and robotics with improved lifetime and recyclability.
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Lei, Kun, Meijun Chen, Xinling Wang, Jingpi Gao, Jianbo Zhang, Guangda Li, Jianfeng Bao, Zhao Li, and Jinghua Li. "Highly stretchable, self-healing elastomer hydrogel with universal adhesion driven by reversible cross-links and protein enhancement." Journal of Materials Chemistry B, 2022. http://dx.doi.org/10.1039/d2tb02015g.
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Engineered hydrogels with excellent mechanical properties and multi-functionality have great potential as soft electronic skins, tissue substitutes and flexible robotic joints. However, it has been a challenge to construct multifunctional...
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Wanasinghe, Shiwanka, Brent Johnson, Rebekah Revadelo, Grant Eifert, Allyson Cox, Joseph Beckett, Timothy Osborn, Carl Thrasher, Robert Lowe, and Dominik Konkolewicz. "3D printable adhesive elastomers with dynamic covalent bond rearrangement." Soft Matter, 2023. http://dx.doi.org/10.1039/d3sm00394a.
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Repairable adhesive elastomers are emerging materials employed in compelling applications such as soft robotics, biosensing, tissue regeneration, and wearable electronics. Facilitating adhesion requires strong interactions, while self-healing requires bond dynamicity....
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Ochirkhuyag, Nyamjargal, Yuji Isano, Kota Inoue, and Hiroki Ota. "Biphasic Liquid Metal Mixtures in Stretchable and Flexible Applications." Sensors & Diagnostics, 2023. http://dx.doi.org/10.1039/d2sd00214k.
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Liquid metals (LMs) have emerged as key materials for soft and wearable electronics because of their unique properties such as fluidity, deformability, low toxicity, high electrical and thermal conductivities, self-healing,...
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Reis Carneiro, Manuel, Carmel Majidi, and Mahmoud Tavakoli. "Gallium‐Based Liquid–Solid Biphasic Conductors for Soft Electronics." Advanced Functional Materials, August 22, 2023. http://dx.doi.org/10.1002/adfm.202306453.
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AbstractSoft and stretchable electronics have diverse applications in the fields of compliant bioelectronics, textile‐integrated wearables, novel forms of mechanical sensors, electronics skins, and soft robotics. In recent years, multiple material architectures have been proposed for highly deformable circuits that can undergo large tensile strains without losing electronic functionality. Among them, gallium‐based liquid metals benefit from fluidic deformability, high electrical conductivity, and self‐healing property. However, their deposition and patterning is challenging. Biphasic material architectures are recently proposed as a method to address this problem, by combining advantages of solid‐phase materials and composites, with liquid deformability and self‐healing of liquid phase conductors, thus moving toward scalable fabrication of reliable stretchable circuits. This article reviews recent biphasic conductor architectures that combine gallium‐based liquid‐phase conductors, with solid‐phase particles and polymers, and their application in fabrication of soft electronic systems. In particular, various material combinations for the solid and liquid phases in the biphasic conductor, as well as methods used to print and pattern biphasic conductive compounds, are discussed. Finally, some applications that benefit from biphasic architectures are reviewed.
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Zhang, Shiyi, Joseph Wang, Kenshi Hayashi, and Fumihiro Sassa. "Monolithic processing of a layered flexible robotic actuator film for kinetic electronics." Scientific Reports 11, no. 1 (October 8, 2021). http://dx.doi.org/10.1038/s41598-021-99500-9.
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AbstractLow-invasive soft robotic techniques can potentially be used for developing next-generation body–machine interfaces. Most soft robots require complicated fabrication processes involving 3D printing and bonding/assembling. In this letter, we describe a monolithic soft microrobot fabrication process for the mass production of soft film robots with a complex structure by simple 2D processing of a robotic actuator film. The 45 µg/mm2 lightweight film robot can be driven at a voltage of CMOS compatible 5 V with 0.15 mm−1 large curvature changes; it can generate a force 5.7 times greater than its self-weight. In a durability test, actuation could be carried out over 8000 times without degradation. To further demonstrate this technique, three types of film robots with multiple degrees of freedom and a moving illuminator robot were fabricated. This technique can easily integrate various electrical circuits developed in the past to robotic systems and can be used for developing advanced wearable sensing devices; it can be called “Kinetic electronics”.
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Wang, Jiemin, Tairan Yang, Zequn Wang, Xuhui Sun, Meng An, Dan Liu, Changsheng Zhao, Gang Zhang, and Weiwei Lei. "A Thermochromic, Viscoelastic Nacre-like Nanocomposite for the Smart Thermal Management of Planar Electronics." Nano-Micro Letters 15, no. 1 (July 5, 2023). http://dx.doi.org/10.1007/s40820-023-01149-8.
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AbstractCutting-edge heat spreaders for soft and planar electronics require not only high thermal conductivity and a certain degree of flexibility but also remarkable self-adhesion without thermal interface materials, elasticity, arbitrary elongation along with soft devices, and smart properties involving thermal self-healing, thermochromism and so on. Nacre-like composites with excellent in-plane heat dissipation are ideal as heat spreaders for thin and planar electronics. However, the intrinsically poor viscoelasticity, i.e., adhesion and elasticity, prevents them from simultaneous self-adhesion and arbitrary elongation along with current flexible devices as well as incurring high interfacial thermal impedance. In this paper, we propose a soft thermochromic composite (STC) membrane with a layered structure, considerable stretchability, high in-plane thermal conductivity (~ 30 W m−1 K−1), low thermal contact resistance (~ 12 mm2 K W−1, 4–5 times lower than that of silver paste), strong yet sustainable adhesion forces (~ 4607 J m−2, 2220 J m−2 greater than that of epoxy paste) and self-healing efficiency. As a self-adhesive heat spreader, it implements efficient cooling of various soft electronics with a temperature drop of 20 °C than the polyimide case. In addition to its self-healing function, the chameleon-like behavior of STC facilitates temperature monitoring by the naked eye, hence enabling smart thermal management.
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Zhao, Xiangjie, Jiaheng Xu, Jingyue Zhang, Mengru Guo, Zhelun Wu, Yueyue Li, Chao Xu, Hongzong Yin, and Xiaolin Wang. "Fluorescent double network ionogel with fast self-healability and high resilience for reliable human motion detection." Materials Horizons, 2023. http://dx.doi.org/10.1039/d2mh01325h.
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Fascinating properties are displayed by high-performance ionogel-based flexible strain sensors, thereby gaining increasing attentions in various applications ranging from human motion monitoring to soft robotics. However, the integration of excellent...
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Liu, Wenbo, Youning Duo, Xingyu Chen, Bohan Chen, Tianzhao Bu, Lei Li, Jinxi Duan, et al. "An Intelligent Robotic System Capable of Sensing and Describing Objects Based on Bimodal, Self‐Powered Flexible Sensors." Advanced Functional Materials, August 24, 2023. http://dx.doi.org/10.1002/adfm.202306368.
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AbstractThis study presents an intelligent soft robotic system capable of perceiving, describing, and sorting objects based on their physical properties. This work introduces a bimodal self‐powered flexible sensor (BSFS) based on the triboelectric nanogenerator and giant magnetoelastic effect. The BSFS features a simplified structure comprising a magnetoelastic conductive film and a packaged liquid metal coil. The BSFS can precisely detect and distinguish touchless and tactile models, with a response time of 10 ms. By seamlessly integrating the BSFSs into the soft fingers, this study realizes an anthropomorphic soft robotic hand with remarkable multimodal perception capabilities. The touchless signals provide valuable insights into object shape and material composition, while the tactile signals offer precise information regarding surface roughness. Utilizing a convolutional neural network (CNN), this study integrates all sensing information, resulting in an intelligent soft robotic system that accurately describes objects based on their physical properties, including materials, surface roughness, and shapes, with an accuracy rate of up to 97%. This study may lay a robotic foundation for the hardware of the general artificial intelligence with capacities to interpret and interact with the physical world, which also serves as an interface between artificial intelligence and soft robots.
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Shang, Yulin, Bingzhen Zhang, Jiyu Liu, Chunwen Xia, Xiaowei Yang, Defeng Yan, and Jing Sun. "Facile and Economical Fabrication of Superhydrophobic Flexible Resistive Strain Sensors for Human Motion Detection." Nanomanufacturing and Metrology 6, no. 1 (March 3, 2023). http://dx.doi.org/10.1007/s41871-023-00183-9.
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AbstractSuperhydrophobic flexible strain sensors have great application value in the fields of personal health monitoring, human motion detection, and soft robotics due to their good flexibility and high sensitivity. However, complicated preparation processes and costly processing procedures have limited their development. To overcome these limitations, in this work we develop a facile and low-cost method for fabricating superhydrophobic flexible strain sensor via spraying carbon black (CB) nanoparticles dispersed in a thermoplastic elastomer (SEBS) solution on a polydimethylsiloxane (PDMS) flexible substrate. The prepared strain sensor had a large water contact angle of 153 ± 2.83° and a small rolling angle of 8.5 ± 1.04°, and exhibited excellent self-cleaning property. Due to the excellent superhydrophobicity, aqueous acid, salt, and alkali could quickly roll off the flexible strain sensor. In addition, the sensor showed excellent sensitivity (gauge factor (GF) of 5.4–7.35), wide sensing ranges (stretching: over 70%), good linearity (three linear regions), low hysteresis (hysteresis error of 4.8%), and a stable response over 100 stretching-releasing cycles. Moreover, the sensor was also capable of effectively detecting human motion signals like finger bending and wrist bending, showing promising application prospects in wearable electronic devices, personalized health monitoring, etc.
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Zolfagharian, Ali, Hamid Reza Jarrah, Matheus Dos Santos Xavier, Bernard Rolfe, and Mahdi Bodaghi. "Multimaterial 4D Printing with Tunable Bending Model." Smart Materials and Structures, April 10, 2023. http://dx.doi.org/10.1088/1361-665x/accba8.
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Abstract Shape-memory polymer-based functional structures may now be produced more efficiently via four-dimensional (4D) printing, benefiting from the recent advances in multi-material three-dimensional (3D) printing technologies. Composite material design using 4D printing has opened new possibilities for customizing the shape memory property of smart polymers. This work studies a design strategy to harness desirable morphing by 4D printing multimaterial composites with a focus on the detailed finite element (FE) procedure, experimental results, and soft robotic application. Composites with bilayer laminates consisting of a shape-memory polymer (SMP) and a flexible elastomer are constructed with variable thickness ratios to control the self-bending of the composite. Finite element simulations are used to understand the underlying processes of composite materials and to generate accurate predictions for the experimental results, which reduces cost and development time. The application of 4D printing and multi-material composite programming is demonstrated with a soft robotic gripper for manipulating fragile objects.
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Mredha, Md Tariful Islam, Yoonseong Lee, Adith Varma Rama Varma, Tanish Gupta, Rumesh Rangana Manimel Wadu, and Insu Jeon. "Tardigrade-inspired extremotolerant glycerogels." NPG Asia Materials 15, no. 1 (April 7, 2023). http://dx.doi.org/10.1038/s41427-023-00472-1.
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AbstractWe developed extremotolerant glycerogels (GGs) with well-modulated polymer structures, functions, and properties, inspired by the tun formation of tardigrades. GGs comprising extreme protected intra- and intermolecular networks are obtained through a very slow structure building process, which includes the smooth replacement of water in predesigned hydrogels with glycerol and thermal annealing while retaining the structures and functions of the original hydrogels. Four different GGs are fabricated as proofs-of-concept using different crosslinkers and polymers. Although various polyol-based wide-temperature-tolerant gels fabricated by conventional methods fail to demonstrate stabilities at low and high temperature extremes simultaneously, the GGs fabricated by our bioinspired method exhibit long-term stability (approaching one month) over an extremely wide temperature range (−50–80 °C) and thermal-shock-absorption capabilities at 150 °C. Furthermore, our versatile method enables us to program GGs with wide ranges of stiffness, strength, stretchability, and toughness values and elasticity, plasticity, hysteresis, and self-recoverability capabilities. The self-weldability, electrical patternability, and applicability characteristics of the GGs as electrolytes and supercapacitors demonstrate their complex 3D designability and facile functionalization capability aspects. The various functional GGs developed through the proposed method are applicable for the design of diverse extremotolerant, flexible, and stretchable devices for biological, electrical/electronic, and soft robotics applications.
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Jafari Horastani, Sahar, Mohammad Ghane, and Mehdi Karevan. "Produce and Performance of a low temperature shape-memory actuator based on twisted-coiled spring mechanics." Smart Materials and Structures, July 15, 2022. http://dx.doi.org/10.1088/1361-665x/ac8192.
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Abstract The demand for new types of actuators continues to grow, and novel approaches have been made possible by the advent of new materials and fabrication strategies. Self-powered actuators have attracted significant attention owing to their ability to be driven by elements in ambient environments. This type of actuator can be used in flexible strain sensors, artificial muscles, soft robotics, and smart breathing textiles. However, petrochemical-based polymers are generally environmentally unfriendly and cause ecological problems. The use of biodegradable polymers is one of the preferred solutions to ecological problems. Polylactic acid is a biodegradable and biocompatible polymer with a high potential. In this study, nanoclay reinforced polylactic acid/thermoplastic polyurethane was used as a precursor. The yarn that was produced was highly twisted. The twisted yarn was then shaped into a coiled structure via mandrel annealing. An apparatus was designed to investigate the thermal actuation behavior of twisted coiled yarn in an isometric state. The blocked force and free stroke were calculated in an isometric state by using linear material equations. The thermal actuation behavior of the twisted coiled yarn was also studied in the isotonic state. This precursor exhibited a considerable two-way shape-memory effect in a twisted coiled structure. It also showed a significant reversible contraction stroke within the ambient temperature range. The theoretical stroke was determined using two different models: the force–stroke equation and spring mechanics. The theoretical results were compared with the experimental results, which revealed acceptable agreement between the theoretical and experimental values.