Abstract
A non-faradaic junction (NFJ) is a connection between an ionic conductor and an electronic conductor in which no electrochemical reaction takes place. The junction behaves like a capacitor and couples the ionic and electronic currents through chemistry, electricity and entropy. Its charge–voltage curve is sensitive to various environmental signals, allowing it to function as a sensor; because no reaction occurs, the sensing is non-destructive and long-lasting. NFJ sensors have high sensitivity, rapid response and small size, and they can be self-powered. These sensors are familiarly used in electrophysiology of the heart, brain and muscles, and applications are emerging in wearable and implantable devices and soft robotics, as well as in sensing pressure, sound, temperature and chemicals. In this Review, we discuss NFJ sensors, emphasizing the development of devices and materials for each side of the junction. The flexibility in choosing materials enables NFJ sensors to fulfil challenging requirements, such as softness, stretchability, transparency and degradability.
This is a preview of subscription content, access via your institution
Access options
Access through your institution
Change institution
Buy or subscribe
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Learn more
Subscribe to this journal
Receive 12 digital issues and online access to articles
$119.00 per year
only $9.92 per issue
Learn more
Buy this article
Purchase on SpringerLink
Instant access to full article PDF
Buy now
Prices may be subject to local taxes which are calculated during checkout
Additional access options:
Log in
Learn about institutional subscriptions
Read our FAQs
Contact customer support
Fig. 1: Principles of non-faradaic junction sensing.
Fig. 2: Characterization of two electrodes in an electrolyte by a sequence of voltage steps.
Fig. 3: Non-faradaic junction pressure sensing.
Fig. 4: Non-faradaic junction acoustic sensing.
Fig. 5: Non-faradaic junction temperature sensing.
Fig. 6: Non-faradaic junction chemical sensing.
References
Hood, L. & Price, N. The Age of Scientific Wellness: Why the Future of Medicine is Personalized, Predictive, Data-Rich, and in Your Hands (Harvard Univ. Press, 2023).
Yang, C. & Suo, Z. Hydrogel ionotronics. Nat. Rev. Mater. 3, 125–142 (2018).
ArticleCASGoogle Scholar
Lee, Y., Song, W. J. & Sun, J. Y. Hydrogel soft robotics. Mater. Today Phys. 15, 100258 (2020).
ArticleGoogle Scholar
Liu, X., Liu, J., Lin, S. & Zhao, X. Hydrogel machines. Mater. Today 36, 102–124 (2020).
ArticleCASGoogle Scholar
Herrmann, A., Haag, R. & Schedler, U. Hydrogels and their role in biosensing applications. Adv. Healthc. Mater. 10, 2100062 (2021).
ArticleCASPubMedPubMed CentralGoogle Scholar
Ying, B. & Liu, X. Skin-like hydrogel devices for wearable sensing, soft robotics and beyond. iScience 24, 103174 (2021).
ArticlePubMedPubMed CentralGoogle Scholar
Xiong, Y., Han, J., Wang, Y., Wang, Z. L. & Sun, Q. Emerging iontronic sensing: materials, mechanisms, and applications. Research 2022, 9867378 (2022).
ArticleCASPubMedPubMed CentralGoogle Scholar
Xiao, K., Wan, C., Jiang, L., Chen, X. & Antonietti, M. Bioinspired ionic sensory systems: the successor of electronics. Adv. Mater. 32, 2000218 (2020).
ArticleCASGoogle Scholar
Steele, B. C. H. & Heinzel, A. Materials for fuel-cell technologies. Nature 414, 345–352 (2001).
ArticleCASPubMedGoogle Scholar
de Vasconcelos, L. S. et al. Chemomechanics of rechargeable batteries: status, theories, and perspectives. Chem. Rev. 122, 13043–13107 (2022).
ArticlePubMedGoogle Scholar
Kimmel, D. W., LeBlanc, G., Meschievitz, M. E. & Cliffel, D. E. Electrochemical sensors and biosensors. Anal. Chem. 84, 685–707 (2012).
ArticleCASPubMedGoogle Scholar
Choi, N.-S. et al. Challenges facing lithium batteries and electrical double-layer capacitors. Angew. Chem. Int. Ed. 51, 9994–10024 (2012).
ArticleCASGoogle Scholar
Keplinger, C. et al. Stretchable, transparent, ionic conductors. Science 341, 984–987 (2013).
ArticleCASPubMedGoogle Scholar
Bard, A. J., Faulkner, L. R., Leddy, J. & Zoski, C. G. Electrochemical Methods: Fundamentals and Applications Vol. 2 (Wiley, 1980).
Kim, D.-H. et al. Epidermal electronics. Science 333, 838–843 (2011).
ArticleCASPubMedGoogle Scholar
Hammock, M. L., Chortos, A., Tee, B. C. K., Tok, J. B. H. & Bao, Z. 25th Anniversary article: the evolution of electronic skin (E-Skin): a brief history, design considerations, and recent progress. Adv. Mater. 25, 5997–6038 (2013).
ArticleCASPubMedGoogle Scholar
Yokota, T. et al. Ultraflexible organic photonic skin. Sci. Adv. 2, e1501856 (2016).
ArticlePubMedPubMed CentralGoogle Scholar
Yang, J. C. et al. Electronic skin: recent progress and future prospects for skin-attachable devices for health monitoring, robotics, and prosthetics. Adv. Mater. 31, 1904765 (2019).
ArticleCASGoogle Scholar
Liu, S., Rao, Y., Jang, H., Tan, P. & Lu, N. Strategies for body-conformable electronics. Matter 5, 1104–1136 (2022).
ArticleCASGoogle Scholar
Rogers, J. A., Someya, T. & Huang, Y. Materials and mechanics for stretchable electronics. Science 327, 1603–1607 (2010).
ArticleCASPubMedGoogle Scholar
Zhang, S. et al. Stretchable electrets: nanoparticle–elastomer composites. Nano Lett. 20, 4580–4587 (2020).
ArticleCASPubMedGoogle Scholar
Luo, Y. et al. Technology roadmap for flexible sensors. ACS Nano 17, 5211–5295 (2023).
ArticleCASPubMedPubMed CentralGoogle Scholar
Elgrishi, N. et al. A practical beginner’s guide to cyclic voltammetry. J. Chem. Educ. 95, 197–206 (2018).
ArticleCASGoogle Scholar
Nie, B., Xing, S., Brandt, J. D. & Pan, T. Droplet-based interfacial capacitive sensing. Lab Chip 12, 1110–1118 (2012).
ArticleCASPubMedGoogle Scholar
Nie, B., Li, R., Brandt, J. D. & Pan, T. Iontronic microdroplet array for flexible ultrasensitive tactile sensing. Lab Chip 14, 1107–1116, (2014).
ArticleCASPubMedGoogle Scholar
Nie, B., Li, R., Cao, J., Brandt, J. D. & Pan, T. Flexible transparent iontronic film for interfacial capacitive pressure sensing. Adv. Mater. 27, 6055–6062 (2015).
ArticleCASPubMedGoogle Scholar
Zhu, Z., Li, R. & Pan, T. Imperceptible epidermal–iontronic interface for wearable sensing. Adv. Mater. 30, 1705122 (2018).
ArticleGoogle Scholar
Heikenfeld, J. et al. Wearable sensors: modalities, challenges, and prospects. Lab Chip 18, 217–248 (2018).
ArticleCASPubMedPubMed CentralGoogle Scholar
Chang, Y. et al. First decade of interfacial iontronic sensing: from droplet sensors to artificial skins. Adv. Mater. 33, 2003464 (2021).
ArticleCASGoogle Scholar
Lu, P. et al. Iontronic pressure sensor with high sensitivity and linear response over a wide pressure range based on soft micropillared electrodes. Sci. Bull. 66, 1091–1100 (2021).
ArticleGoogle Scholar
Zhu, P. et al. Skin–electrode iontronic interface for mechanosensing. Nat. Commun. 12, 4731 (2021).
ArticleCASPubMedPubMed CentralGoogle Scholar
Yang, R. et al. Iontronic pressure sensor with high sensitivity over ultra-broad linear range enabled by laser-induced gradient micro-pyramids. Nat. Commun. 14, 2907 (2023).
ArticleCASPubMedPubMed CentralGoogle Scholar
Cho, S. H. et al. Micropatterned pyramidal ionic gels for sensing broad-range pressures with high sensitivity. ACS Appl. Mater. Interfaces 9, 10128–10135 (2017).
ArticleCASPubMedGoogle Scholar
Li, R. et al. Supercapacitive iontronic nanofabric sensing. Adv. Mater. 29, 1700253 (2017).
ArticleGoogle Scholar
Chhetry, A., Kim, J., Yoon, H. & Park, J. Y. Ultrasensitive interfacial capacitive pressure sensor based on a randomly distributed microstructured iontronic film for wearable applications. ACS Appl. Mater. Interfaces 11, 3438–3449 (2019).
ArticleCASPubMedGoogle Scholar
Bai, N. et al. Graded intrafillable architecture-based iontronic pressure sensor with ultra-broad-range high sensitivity. Nat. Commun. 11, 209 (2020).
ArticleCASPubMedPubMed CentralGoogle Scholar
Xiao, Y. et al. Multilayer double-sided microstructured flexible iontronic pressure sensor with a record-wide linear working range. ACS Sens. 6, 1785–1795 (2021).
ArticleCASPubMedGoogle Scholar
Bai, N. et al. Graded interlocks for iontronic pressure sensors with high sensitivity and high linearity over a broad range. ACS Nano 16, 4338–4347 (2022).
ArticleCASPubMedGoogle Scholar
Jin, M. L. et al. An ultrasensitive, visco-poroelastic artificial mechanotransducer skin inspired by piezo2 protein in mammalian Merkel cells. Adv. Mater. 29, 1605973 (2017).
ArticleGoogle Scholar
Choi, D. et al. A highly sensitive tactile sensor using a pyramid-plug structure for detecting pressure, shear force, and torsion. Adv. Mater. Technol. 4, 1800284 (2019).
ArticleGoogle Scholar
Yuan, Y.-M. et al. Microstructured polyelectrolyte elastomer-based ionotronic sensors with high sensitivities and excellent stability for artificial skins. Adv. Mater. 36, 2310429 (2024).
ArticleCASGoogle Scholar
Gao, Y. et al. Hydrogel microphones for stealthy underwater listening. Nat. Commun. 7, 12316 (2016).
ArticleCASPubMedPubMed CentralGoogle Scholar
Wang, M. et al. Ionogel microphones detect underwater sound with directivity and exceptional stability. ACS Appl. Electron. Mater. 2, 1295–1303 (2020).
ArticleCASGoogle Scholar
Li, S. et al. Gate-free hydrogel–graphene transistors as underwater microphones. ACS Appl. Mater. Interfaces 10, 42573–42582 (2018).
ArticleCASPubMedGoogle Scholar
Wang, Y. et al. Temperature sensing using junctions between mobile ions and mobile electrons. Proc. Natl Acad. Sci. USA 119, e2117962119 (2022).
ArticleCASPubMedPubMed CentralGoogle Scholar
Webb, R. C. et al. Ultrathin conformal devices for precise and continuous thermal characterization of human skin. Nat. Mater. 12, 938 (2013).
ArticleCASPubMedPubMed CentralGoogle Scholar
Yokota, T. et al. Ultraflexible, large-area, physiological temperature sensors for multipoint measurements. Proc. Natl Acad. Sci. USA 112, 14533–14538 (2015).
ArticleCASPubMedPubMed CentralGoogle Scholar
Trung, T. Q., Ramasundaram, S., Hwang, B.-U. & Lee, N.-E. An all-elastomeric transparent and stretchable temperature sensor for body-attachable wearable electronics. Adv. Mater. 28, 502–509 (2016).
ArticleCASPubMedGoogle Scholar
Wu, J. et al. Highly stretchable and transparent thermistor based on self-healing double network hydrogel. ACS Appl. Mater. Interfaces 10, 19097–19105 (2018).
ArticleCASPubMedGoogle Scholar
Wu, Z. et al. Ultrasensitive, stretchable, and fast-response temperature sensors based on hydrogel films for wearable applications. ACS Appl. Mater. Interfaces 13, 21854–21864 (2021).
ArticleCASPubMedGoogle Scholar
Schöning, M. J. & Poghossian, A. Recent advances in biologically sensitive field-effect transistors (BioFETs). Analyst 127, 1137–1151 (2002).
ArticlePubMedGoogle Scholar
Palazzo, G. et al. Detection beyond Debye’s length with an electrolyte-gated organic field-effect transistor. Adv. Mater. 27, 911–916 (2015).
ArticleCASPubMedGoogle Scholar
Hafeman, D. G., Parce, J. W. & McConnell, H. M. Light-addressable potentiometric sensor for biochemical systems. Science 240, 1182–1185 (1988).
ArticleCASPubMedGoogle Scholar
Du, L. et al. Dual functional extracellular recording using a light-addressable potentiometric sensor for bitter signal transduction. Anal. Chim. Acta 1022, 106–112 (2018).
ArticleCASPubMedGoogle Scholar
Liu, Y.-L. et al. Electrical double layer-based iontronic sensor for detection of electrolytes concentration. Chin. J. Anal. Chem. 50, 13–19 (2022).
ArticleGoogle Scholar
Wang, Y., Zhang, S., Bai, Y., Jia, K. & Suo, Z. Chemical sensing by interfacial voltage. Cell Rep. Phys. Sci. 3, 101119 (2022).
ArticleCASGoogle Scholar
Björneholm, O., Nilsson, A., Sandell, A., Hernnäs, B. & Mrtensson, N. Determination of time scales for charge-transfer screening in physisorbed molecules. Phys. Rev. Lett. 68, 1892–1895 (1992).
ArticlePubMedGoogle Scholar
Zangi, R. & Engberts, J. B. F. N. Physisorption of hydroxide ions from aqueous solution to a hydrophobic surface. J. Am. Chem. Soc. 127, 2272–2276 (2005).
ArticleCASPubMedGoogle Scholar
Jiang, Y. et al. Frequency-dependent electrochemical breakdown of hydrogel ionotronics. Extrem. Mech. Lett. 71, 102210 (2024).
ArticleGoogle Scholar
Zhang, Y. et al. Microstructures and properties of high-entropy alloys. Prog. Mater. Sci. 61, 1–93 (2014).
ArticleGoogle Scholar
Miracle, D. B. & Senkov, O. N. A critical review of high entropy alloys and related concepts. Acta Mater. 122, 448–511 (2017).
ArticleCASGoogle Scholar
George, E. P., Raabe, D. & Ritchie, R. O. High-entropy alloys. Nat. Rev. Mater. 4, 515–534 (2019).
ArticleCASGoogle Scholar
Kong, K., Hyun, J., Kim, Y., Kim, W. & Kim, D. Nanoporous structure synthesized by selective phase dissolution of AlCoCrFeNi high entropy alloy and its electrochemical properties as supercapacitor electrode. J. Power Sources 437, 226927 (2019).
ArticleCASGoogle Scholar
Lee, J. A. et al. Ultrafast charge and discharge biscrolled yarn supercapacitors for textiles and microdevices. Nat. Commun. 4, 1970 (2013).
ArticlePubMedGoogle Scholar
Baughman, R. H. et al. Carbon nanotube actuators. Science 284, 1340–1344 (1999).
ArticleCASPubMedGoogle Scholar
Torop, J. et al. Flexible supercapacitor-like actuator with carbide-derived carbon electrodes. Carbon 49, 3113–3119 (2011).
ArticleCASGoogle Scholar
Foroughi, J. et al. Knitted carbon-nanotube-sheath/spandex-core elastomeric yarns for artificial muscles and strain sensing. ACS Nano 10, 9129–9135 (2016).
ArticleCASPubMedGoogle Scholar
Nezakati, T., Seifalian, A., Tan, A. & Seifalian, A. M. Conductive polymers: opportunities and challenges in biomedical applications. Chem. Rev. 118, 6766–6843 (2018).
ArticleCASPubMedGoogle Scholar
Zhang, W., Dehghani-Sanij, A. A. & Blackburn, R. S. Carbon based conductive polymer composites. J. Mater. Sci. 42, 3408–3418 (2007).
ArticleCASGoogle Scholar
Kumar, D. & Sharma, R. C. Advances in conductive polymers. Eur. Polym. J. 34, 1053–1060 (1998).
ArticleCASGoogle Scholar
Yao, B. et al. Ultrastrong, highly conductive and capacitive hydrogel electrode for electron-ion transduction. Matter 5, 4407–4424 (2022).
ArticleCASGoogle Scholar
Cui, M., Zhang, C., Mo, J. & Wang, Z. A general strategy to achieve high-fidelity electron-ion transduction. Matter 5, 4107–4109 (2022).
ArticleCASGoogle Scholar
Lacour, S. P., Wagner, S., Huang, Z. & Suo, Z. Stretchable gold conductors on elastomeric substrates. Appl. Phys. Lett. 82, 2404–2406 (2003).
ArticleCASGoogle Scholar
Li, T., Huang, Z., Suo, Z., Lacour, S. P. & Wagner, S. Stretchability of thin metal films on elastomer substrates. Appl. Phys. Lett. 85, 3435–3437 (2004).
ArticleCASGoogle Scholar
Lacour, S. P., Jones, J., Suo, Z. & Wagner, S. Design and performance of thin metal film interconnects for skin-like electronic circuits. IEEE Electron. Device Lett. 25, 179–181 (2004).
ArticleCASGoogle Scholar
Guo, C. F., Sun, T., Liu, Q., Suo, Z. & Ren, Z. Highly stretchable and transparent nanomesh electrodes made by grain boundary lithography. Nat. Commun. 5, 3121 (2014).
ArticlePubMedGoogle Scholar
Guo, C. F. et al. Fatigue-free, superstretchable, transparent, and biocompatible metal electrodes. Proc. Natl Acad. Sci. USA 112, 12332–12337 (2015).
ArticleCASPubMedPubMed CentralGoogle Scholar
Wu, Y., Xiang, J., Yang, C., Lu, W. & Lieber, C. M. Single-crystal metallic nanowires and metal/semiconductor nanowire heterostructures. Nature 430, 61–65 (2004).
ArticleCASPubMedGoogle Scholar
Won, P. et al. Stretchable and transparent kirigami conductor of nanowire percolation network for electronic skin applications. Nano Lett. 19, 6087–6096 (2019).
ArticleCASPubMedGoogle Scholar
Wang, Y. et al. A highly stretchable, transparent, and conductive polymer. Sci. Adv. 3, e1602076 (2017).
ArticlePubMedPubMed CentralGoogle Scholar
Root, S. E., Savagatrup, S., Printz, A. D., Rodriquez, D. & Lipomi, D. J. Mechanical properties of organic semiconductors for stretchable, highly flexible, and mechanically robust electronics. Chem. Rev. 117, 6467–6499 (2017).
ArticleCASPubMedGoogle Scholar
O’Connor, T. F., Rajan, K. M., Printz, A. D. & Lipomi, D. J. Toward organic electronics with properties inspired by biological tissue. J. Mater. Chem. B 3, 4947–4952 (2015).
ArticlePubMedGoogle Scholar
Zu, M., Li, Q., Wang, G., Byun, J.-H. & Chou, T.-W. Carbon nanotube fiber based stretchable conductor. Adv. Funct. Mater. 23, 789–793 (2013).
ArticleCASGoogle Scholar
Song, P., Song, J. & Zhang, Y. Stretchable conductor based on carbon nanotube/carbon black silicone rubber nanocomposites with highly mechanical, electrical properties and strain sensitivity. Compos. B Eng. 191, 107979 (2020).
ArticleCASGoogle Scholar
Xu, F., Wang, X., Zhu, Y. & Zhu, Y. Wavy ribbons of carbon nanotubes for stretchable conductors. Adv. Funct. Mater. 22, 1279–1283 (2012).
ArticleCASGoogle Scholar
Song, C. et al. A printed highly stretchable supercapacitor by a combination of carbon ink and polymer network. Extrem. Mech. Lett. 49, 101459 (2021).
ArticleGoogle Scholar
Chun, K.-Y. et al. Highly conductive, printable and stretchable composite films of carbon nanotubes and silver. Nat. Nanotechnol. 5, 853–857 (2010).
ArticleCASPubMedGoogle Scholar
Li, D., Lai, W.-Y., Zhang, Y.-Z. & Huang, W. Printable transparent conductive films for flexible electronics. Adv. Mater. 30, 1704738 (2018).
ArticleGoogle Scholar
Huang, Q. & Zhu, Y. Printing conductive nanomaterials for flexible and stretchable electronics: a review of materials, processes, and applications. Adv. Mater. Technol. 4, 1800546 (2019).
ArticleGoogle Scholar
Rosset, S. & Shea, H. R. Flexible and stretchable electrodes for dielectric elastomer actuators. Appl. Phys. A 110, 281–307 (2013).
ArticleCASGoogle Scholar
McCoul, D., Hu, W., Gao, M., Mehta, V. & Pei, Q. Recent advances in stretchable and transparent electronic materials. Adv. Electron. Mater. 2, 1500407 (2016).
ArticleGoogle Scholar
Matsuhisa, N., Chen, X., Bao, Z. & Someya, T. Materials and structural designs of stretchable conductors. Chem. Soc. Rev. 48, 2946–2966 (2019).
ArticleCASPubMedGoogle Scholar
Chen, Z. H., Fang, R., Li, W. & Guan, J. Stretchable transparent conductors: from micro/macromechanics to applications. Adv. Mater. 31, 1900756 (2019).
ArticleGoogle Scholar
Kim, K., Park, Y.-G., Hyun, B. G., Choi, M. & Park, J.-U. Recent advances in transparent electronics with stretchable forms. Adv. Mater. 31, 1804690 (2019).
ArticleGoogle Scholar
Li, Y. et al. A lithium superionic conductor for millimeter-thick battery electrode. Science 381, 50–53 (2023).
ArticleCASPubMedGoogle Scholar
Buwalda, S. J. et al. Hydrogels in a historical perspective: from simple networks to smart materials. J. Control. Rel. 190, 254–273 (2014).
ArticleCASGoogle Scholar
Wichterle, O. & LÍM, D. Hydrophilic gels for biological use. Nature 185, 117–118 (1960).
ArticleGoogle Scholar
Masuda, F. in Superabsorbent Polymers 573, ACS Symposium Series 88–98 (American Chemical Society, 1994).
Langer, R. Drug delivery and targeting. Nature 392, 5–10 (1998).
CASPubMedGoogle Scholar
Li, J. & Mooney, D. J. Designing hydrogels for controlled drug delivery. Nat. Rev. Mater. 1, 16071 (2016).
ArticleCASPubMedPubMed CentralGoogle Scholar
Naahidi, S. et al. Biocompatibility of hydrogel-based scaffolds for tissue engineering applications. Biotechnol. Adv. 35, 530–544 (2017).
ArticleCASPubMedGoogle Scholar
Wan, C., Xiao, K., Angelin, A., Antonietti, M. & Chen, X. The rise of bioinspired ionotronics. Adv. Intell. Syst. 1, 1900073 (2019).
ArticleGoogle Scholar
Lee, H.-R., Kim, C.-C. & Sun, J.-Y. Stretchable ionics — a promising candidate for upcoming wearable devices. Adv. Mater. 30, 1704403 (2018).
ArticleGoogle Scholar
Jia, K., Li, X. & Wang, Y. Electrochemical breakdown in hydrogel ionotronic devices. Soft Matter 17, 834–839 (2021).
ArticleCASPubMedGoogle Scholar
Kellaris, N., Gopaluni Venkata, V., Smith, G. M., Mitchell, S. K. & Keplinger, C. Peano-HASEL actuators: muscle-mimetic, electrohydraulic transducers that linearly contract on activation. Sci. Robot. 3, eaar3276 (2018).
ArticlePubMedGoogle Scholar
Acome, E. et al. Hydraulically amplified self-healing electrostatic actuators with muscle-like performance. Science 359, 61–65 (2018).
ArticleCASPubMedGoogle Scholar
Yang, C. H. et al. Ionic cable. Extrem. Mech. Lett. 3, 59–65 (2015).
ArticleGoogle Scholar
Wang, Y., Xie, S., Bai, Y., Suo, Z. & Jia, K. Transduction between magnets and ions. Mater. Horiz. 8, 1959–1965 (2021).
ArticleCASPubMedGoogle Scholar
Sun, J.-Y., Keplinger, C., Whitesides, G. M. & Suo, Z. Ionic skin. Adv. Mater. 26, 7608–7614 (2014).
ArticleCASPubMedGoogle Scholar
Kim, C.-C., Lee, H.-H., Oh, K. H. & Sun, J.-Y. Highly stretchable, transparent ionic touch panel. Science 353, 682–687 (2016).
ArticleCASPubMedGoogle Scholar
Yang, C. H., Chen, B., Zhou, J., Chen, Y. M. & Suo, Z. Electroluminescence of giant stretchability. Adv. Mater. 28, 4480–4484 (2016).
ArticleCASPubMedGoogle Scholar
Larson, C. et al. Highly stretchable electroluminescent skin for optical signaling and tactile sensing. Science 351, 1071–1074 (2016).
ArticleCASPubMedGoogle Scholar
Yang, C. et al. Ionotronic luminescent fibers, fabrics, and other configurations. Adv. Mater. 32, 2005545 (2020).
ArticleCASGoogle Scholar
Schroeder, T. B. H. et al. An electric-eel-inspired soft power source from stacked hydrogels. Nature 552, 214–218 (2017).
ArticleCASPubMedPubMed CentralGoogle Scholar
Dobashi, Y. et al. Piezoionic mechanoreceptors: force-induced current generation in hydrogels. Science 376, 502–507 (2022).
ArticleCASPubMedGoogle Scholar
Cayre, O. J., Chang, S. T. & Velev, O. D. Polyelectrolyte diode: nonlinear current response of a junction between aqueous ionic gels. J. Am. Chem. Soc. 129, 10801–10806 (2007).
ArticleCASPubMedGoogle Scholar
Lim, S.-M. et al. Ion-to-ion amplification through an open-junction ionic diode. Proc. Natl Acad. Sci. USA 116, 13807–13815 (2019).
ArticleCASPubMedPubMed CentralGoogle Scholar
Lee, H.-R. et al. A stretchable ionic diode from copolyelectrolyte hydrogels with methacrylated polysaccharides. Adv. Funct. Mater. 29, 1806909 (2019).
ArticleGoogle Scholar
Wang, Y., Wang, Z., Su, Z. & Cai, S. Stretchable and transparent ionic diode and logic gates. Extrem. Mech. Lett. 28, 81–86 (2019).
ArticleGoogle Scholar
Chen, B. et al. Highly stretchable and transparent ionogels as nonvolatile conductors for dielectric elastomer transducers. ACS Appl. Mater. Interfaces 6, 7840–7845 (2014).
ArticleCASPubMedGoogle Scholar
Yiming, B. et al. Ambiently and mechanically stable ionogels for soft ionotronics. Adv. Funct. Mater. 31, 2102773 (2021).
ArticleCASGoogle Scholar
Ren, Y. et al. Ionic liquid-based click-ionogels. Sci. Adv. 5, eaax0648 (2019).
ArticleCASPubMedPubMed CentralGoogle Scholar
Li, T., Wang, Y., Li, S., Liu, X. & Sun, J. Mechanically robust, elastic, and healable ionogels for highly sensitive ultra-durable ionic skins. Adv. Mater. 32, 2002706 (2020).
ArticleGoogle Scholar
Gao, Y. et al. Highly stretchable organogel ionic conductors with extreme-temperature tolerance. Chem. Mater. 31, 3257–3264 (2019).
ArticleCASGoogle Scholar
Zhang, L. et al. Stretchable and transparent ionogel-based heaters. Mater. Horiz. 9, 1911–1920 (2022).
ArticleCASPubMedGoogle Scholar
Shi, L. et al. Highly stretchable and transparent ionic conductor with novel hydrophobicity and extreme-temperature tolerance. Research 2020, 2505619 (2020).
ArticleCASPubMedPubMed CentralGoogle Scholar
Zhao, Y. et al. A self-healing electrically conductive organogel composite. Nat. Electron. 6, 206–215 (2023).
ArticleCASGoogle Scholar
Park, J.-M., Lim, S. & Sun, J.-Y. Materials development in stretchable iontronics. Soft Matter 18, 6487–6510 (2022).
ArticleCASPubMedGoogle Scholar
Chen, N., Zhang, H., Li, L., Chen, R. & Guo, S. Ionogel electrolytes for high-performance lithium batteries: a review. Adv. Energy Mater. 8, 1702675 (2018).
ArticleGoogle Scholar
Kuzina, M. A., Kartsev, D. D., Stratonovich, A. V. & Levkin, P. A. Organogels versus hydrogels: advantages, challenges, and applications. Adv. Funct. Mater. 33, 2301421 (2023).
ArticleCASGoogle Scholar
Kim, H. J., Chen, B., Suo, Z. & Hayward, R. C. Ionoelastomer junctions between polymer networks of fixed anions and cations. Science 367, 773–776 (2020).
ArticleCASPubMedGoogle Scholar
Li, C. et al. Polyelectrolyte elastomer-based ionotronic sensors with multi-mode sensing capabilities via multi-material 3D printing. Nat. Commun. 14, 4853 (2023).
ArticleCASPubMedPubMed CentralGoogle Scholar
Zhang, C. et al. 3D printed, solid-state conductive ionoelastomer as a generic building block for tactile applications. Adv. Mater. 34, 2105996 (2022).
ArticleCASGoogle Scholar
Jo, C., Pugal, D., Oh, I.-K., Kim, K. J. & Asaka, K. Recent advances in ionic polymer–metal composite actuators and their modeling and applications. Prog. Polym. Sci. 38, 1037–1066 (2013).
ArticleCASGoogle Scholar
Kamamichi, N., Yamakita, M., Asaka, K. & Zhi-Wei, L. A Snake-like Swimming Robot using IPMC Actuator/Sensor. in Proceedings 2006 IEEE International Conference on Robotics and Automation . ICRA 2006. 1812–1817 (IEEE, 2006).
Mirfakhrai, T., Madden, J. D. W. & Baughman, R. H. Polymer artificial muscles. Mater. Today 10, 30–38 (2007).
ArticleCASGoogle Scholar
Mauritz, K. A. & Moore, R. B. State of understanding of nafion. Chem. Rev. 104, 4535–4586 (2004).
ArticleCASPubMedGoogle Scholar
Zhao, X. et al. Soft materials by design: unconventional polymer networks give extreme properties. Chem. Rev. 121, 4309–4372 (2021).
ArticleCASPubMedPubMed CentralGoogle Scholar
Zou, W., Dong, J., Luo, Y., Zhao, Q. & Xie, T. Dynamic covalent polymer networks: from old chemistry to modern day innovations. Adv. Mater. 29, 1606100 (2017).
ArticleGoogle Scholar
Zheng, N., Xu, Y., Zhao, Q. & Xie, T. Dynamic covalent polymer networks: a molecular platform for designing functions beyond chemical recycling and self-healing. Chem. Rev. 121, 1716–1745 (2021).
ArticleCASPubMedGoogle Scholar
Shi, Q., Jin, C., Chen, Z., An, L. & Wang, T. On the welding of vitrimers: chemistry, mechanics and applications. Adv. Funct. Mater. 33, 2300288 (2023).
ArticleCASGoogle Scholar
Shi, Q., Yu, K., Dunn, M. L., Wang, T. & Qi, H. J. Solvent assisted pressure-free surface welding and reprocessing of malleable epoxy polymers. Macromolecules 49, 5527–5537 (2016).
ArticleCASGoogle Scholar
Yu, K. et al. Interfacial welding of dynamic covalent network polymers. J. Mech. Phys. Solids 94, 1–17 (2016).
ArticleCASGoogle Scholar
An, L., Shi, Q., Jin, C., Zhao, W. & Wang, T. J. Chain diffusion based framework for modeling the welding of vitrimers. J. Mech. Phys. Solids 164, 104883 (2022).
ArticleCASGoogle Scholar
Bui, K. et al. Stretchable, healable, and weldable vitrimer ionogel for ionotronic applications. Chem. Eng. J. 474, 145533 (2023).
ArticleCASGoogle Scholar
Peri, J. B. & Hannan, R. B. Surface hydroxyl groups on Γ-alumina1. J. Phys. Chem. 64, 1526–1530 (1960).
ArticleCASGoogle Scholar
Tamura, H., Mita, K., Tanaka, A. & Ito, M. Mechanism of hydroxylation of metal oxide surfaces. J. Colloid Interface Sci. 243, 202–207 (2001).
ArticleCASGoogle Scholar
Wang, Y. et al. Instant, tough, noncovalent adhesion. ACS Appl. Mater. Interfaces 11, 40749–40757 (2019).
ArticleCASPubMedGoogle Scholar
Suo, Z. Theory of dielectric elastomers. Acta Mech. Solid Sin. 23, 549–578 (2010).
ArticleGoogle Scholar
Pelrine, R., Kornbluh, R., Pei, Q. & Joseph, J. High-speed electrically actuated elastomers with strain greater than 100%. Science 287, 836–839 (2000).
ArticleCASPubMedGoogle Scholar
Lu, T., Ma, C. & Wang, T. Mechanics of dielectric elastomer structures: a review. Extrem. Mech. Lett. 38, 100752 (2020).
ArticleGoogle Scholar
Lu, T., An, L., Li, J., Yuan, C. & Wang, T. J. Electro-mechanical coupling bifurcation and bulging propagation in a cylindrical dielectric elastomer tube. J. Mech. Phys. Solids 85, 160–175 (2015).
ArticleGoogle Scholar
An, L., Wang, F., Cheng, S., Lu, T. & Wang, T. J. Experimental investigation of the electromechanical phase transition in a dielectric elastomer tube. Smart Mater. Struct. 24, 035006 (2015).
ArticleGoogle Scholar
Le Floch, P. et al. Fundamental limits to the electrochemical impedance stability of dielectric elastomers in bioelectronics. Nano Lett. 20, 224–233 (2020).
ArticlePubMedGoogle Scholar
Gong, J. P., Katsuyama, Y., Kurokawa, T. & Osada, Y. Double-network hydrogels with extremely high mechanical strength. Adv. Mater. 15, 1155–1158 (2003).
ArticleCASGoogle Scholar
Sun, J.-Y. et al. Highly stretchable and tough hydrogels. Nature 489, 133 (2012).
ArticleCASPubMedPubMed CentralGoogle Scholar
Kim, J., Zhang, G., Shi, M. & Suo, Z. Fracture, fatigue, and friction of polymers in which entanglements greatly outnumber cross-links. Science 374, 212–216 (2021).
ArticleCASPubMedGoogle Scholar
Hua, M. et al. Strong tough hydrogels via the synergy of freeze-casting and salting out. Nature 590, 594–599 (2021).
ArticleCASPubMedGoogle Scholar
Xiang, C. et al. Stretchable and fatigue-resistant materials. Mater. Today 34, 7–16 (2020).
ArticleCASGoogle Scholar
Mu, R. et al. Polymer-filled macroporous hydrogel for low friction. Extrem. Mech. Lett. 38, 100742 (2020).
ArticleGoogle Scholar
Xing, H. et al. Strong, tough, fatigue-resistant and 3D-printable hydrogel composites reinforced by aramid nanofibers. Mater. Today 68, 84–95 (2023).
ArticleCASGoogle Scholar
Wang, Y., Nian, G., Kim, J. & Suo, Z. Polyacrylamide hydrogels. VI. Synthesis–property relation. J. Mech. Phys. Solids 170, 105099 (2023).
ArticleCASGoogle Scholar
Wang, Y. & Sun, D. Relation of synthesis and fatigue property in elastic soft materials. J. Mech. Phys. Solids 193, 105894 (2024).
ArticleCASGoogle Scholar
Zhao, X. Multi-scale multi-mechanism design of tough hydrogels: building dissipation into stretchy networks. Soft Matter 10, 672–687 (2014).
ArticleCASPubMedPubMed CentralGoogle Scholar
Yang, C., Yin, T. & Suo, Z. Polyacrylamide hydrogels. I. Network imperfection. J. Mech. Phys. Solids 131, 43–55 (2019).
ArticleCASGoogle Scholar
Liu, J. et al. Polyacrylamide hydrogels. II. elastic dissipater. J. Mech. Phys. Solids 133, 103737 (2019).
ArticleCASGoogle Scholar
Wang, Y., Yin, T. & Suo, Z. Polyacrylamide hydrogels. III. Lap shear and peel. J. Mech. Phys. Solids 150, 104348 (2021).
ArticleCASGoogle Scholar
Hassan, S., Kim, J. & Suo, Z. Polyacrylamide hydrogels. IV. Near-perfect elasticity and rate-dependent toughness. J. Mech. Phys. Solids 158, 104675 (2022).
ArticleCASGoogle Scholar
Kim, J., Yin, T. & Suo, Z. Polyacrylamide hydrogels. V. Some strands in a polymer network bear loads, but all strands contribute to swelling. J. Mech. Phys. Solids 168, 105017 (2022).
ArticleCASGoogle Scholar
Wang, Y., Liang, D., Suo, Z. & Jia, K. Synergy of noncovalent interlink and covalent toughener for tough hydrogel adhesion. Extrem. Mech. Lett. 39, 100797 (2020).
ArticleGoogle Scholar
Yuk, H., Zhang, T., Lin, S., Parada, G. A. & Zhao, X. Tough bonding of hydrogels to diverse non-porous surfaces. Nat. Mater. 15, 190–196 (2016).
ArticleCASPubMedGoogle Scholar
Yuk, H., Zhang, T., Parada, G. A., Liu, X. & Zhao, X. Skin-inspired hydrogel–elastomer hybrids with robust interfaces and functional microstructures. Nat. Commun. 7, 12028 (2016).
ArticlePubMedPubMed CentralGoogle Scholar
Yang, J., Bai, R. & Suo, Z. Topological adhesion of wet materials. Adv. Mater. 30, 1800671 (2018).
ArticleGoogle Scholar
Gao, Y. et al. A universal strategy for tough adhesion of wet soft material. Adv. Funct. Mater. 30, 2003207 (2020).
ArticleCASGoogle Scholar
Yang, J., Bai, R., Chen, B. & Suo, Z. Hydrogel adhesion: a supramolecular synergy of chemistry, topology, and mechanics. Adv. Funct. Mater. 30, 1901693 (2020).
ArticleCASGoogle Scholar
Wang, Y., Yang, X., Nian, G. & Suo, Z. Strength and toughness of adhesion of soft materials measured in lap shear. J. Mech. Phys. Solids 143, 103988 (2020).
ArticleGoogle Scholar
Wang, Y., Nian, G., Yang, X. & Suo, Z. Lap shear of a soft and elastic adhesive. Mech. Mater. 158, 103845 (2021).
ArticleGoogle Scholar
Fleck, N. A., Kang, K. J. & Ashby, M. F. Overview no. 112: the cyclic properties of engineering materials. Acta Metall. Mater. 42, 365–381 (1994).
ArticleCASGoogle Scholar
Ritchie, R. O. Mechanisms of fatigue crack propagation in metals, ceramics and composites: role of crack tip shielding. Mater. Sci. Eng. A 103, 15–28 (1988).
ArticleGoogle Scholar
Suresh, S. Fatigue of Materials 2nd edn (Cambridge Univ. Press, 1998).
Mars, W. V. & Fatemi, A. Factors that affect the fatigue life of rubber: a literature survey. Rubber Chem. Technol. 77, 391–412 (2004).
ArticleCASGoogle Scholar
Bai, R., Yang, J. & Suo, Z. Fatigue of hydrogels. Eur. J. Mech. A/Solids 74, 337–370 (2019).
ArticleGoogle Scholar
Han, Z., Lu, Y. & Qu, S. Design of fatigue-resistant hydrogels. Adv. Funct. Mater. 34, 2313498 (2024).
ArticleCASGoogle Scholar
Steck, J., Kim, J., Kutsovsky, Y. & Suo, Z. Multiscale stress deconcentration amplifies fatigue resistance of rubber. Nature 624, 303–308 (2023).
ArticleCASPubMedGoogle Scholar
Wang, Z. et al. Stretchable materials of high toughness and low hysteresis. Proc. Natl Acad. Sci. USA 116, 5967–5972 (2019).
ArticleCASPubMedPubMed CentralGoogle Scholar
Lin, S. et al. Anti-fatigue-fracture hydrogels. Sci. Adv. 5, eaau8528 (2019).
ArticlePubMedPubMed CentralGoogle Scholar
Li, X. et al. Mesoscale bicontinuous networks in self-healing hydrogels delay fatigue fracture. Proc. Natl Acad. Sci. USA 117, 7606–7612 (2020).
ArticleCASPubMedPubMed CentralGoogle Scholar
Lin, S., Liu, J., Liu, X. & Zhao, X. Muscle-like fatigue-resistant hydrogels by mechanical training. Proc. Natl Acad. Sci. USA 116, 10244–10249 (2019).
ArticleCASPubMedPubMed CentralGoogle Scholar
Sun, D. et al. Enhance fracture toughness and fatigue resistance of hydrogels by reversible alignment of nanofibers. ACS Appl. Mater. Interfaces 14, 49389–49397 (2022).
ArticleCASPubMedGoogle Scholar
Liu, B. et al. Tough and fatigue-resistant polymer networks by crack tip softening. Proc. Natl Acad. Sci. USA 120, e2217781120 (2023).
ArticlePubMedPubMed CentralGoogle Scholar
Yang, H., Chen, X., Sun, B., Tang, J. & Vlassak, J. J. Fracture tolerance induced by dynamic bonds in hydrogels. J. Mech. Phys. Solids 169, 105083 (2022).
ArticleCASGoogle Scholar
Parsons, R. The electrical double layer: recent experimental and theoretical developments. Chem. Rev. 90, 813–826 (1990).
ArticleCASGoogle Scholar
Favaro, M. et al. Unravelling the electrochemical double layer by direct probing of the solid/liquid interface. Nat. Commun. 7, 12695 (2016).
ArticleCASPubMedPubMed CentralGoogle Scholar
Brown, M. A. et al. Determination of surface potential and electrical double-layer structure at the aqueous electrolyte–nanoparticle interface. Phys. Rev. X 6, 011007 (2016).
Google Scholar
Brown, M. A., Goel, A. & Abbas, Z. Effect of electrolyte concentration on the stern layer thickness at a charged interface. Angew. Chem. Int. Ed. 55, 3790–3794 (2016).
ArticleCASGoogle Scholar
Shi, Q. et al. Recyclable 3D printing of vitrimer epoxy. Mater. Horiz. 4, 598–607 (2017).
ArticleCASGoogle Scholar
Kuang, X. et al. Advances in 4D printing: materials and applications. Adv. Funct. Mater. 29, 1805290 (2019).
ArticleGoogle Scholar
Download references
Acknowledgements
Y.W. acknowledges the support of NSFC (12302225). K.J. acknowledges the support of NSFC (81974470). Z.S. acknowledges the support of the NSF through the Harvard University Materials Research Science and Engineering Center (DMR2011754) and the support of the Air Force Office of Scientific Research (FA9550-20-1-0397).
Author information
Authors and Affiliations
Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou, China
Yecheng Wang
State Key Laboratory for Strength and Vibration of Mechanical Structures, Department of Engineering Mechanics, Xi’an Jiaotong University, Xi’an, China
Kun Jia
John A. Paulson School of Engineering and Applied Sciences, Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, MA, USA
Zhigang Suo
Authors
Yecheng Wang
View author publications
You can also search for this author in PubMedGoogle Scholar
2. Kun Jia
View author publications
You can also search for this author in PubMedGoogle Scholar
3. Zhigang Suo
View author publications
You can also search for this author in PubMedGoogle Scholar
Contributions
All authors contributed equally to the manuscript.
Corresponding authors
Correspondence to Yecheng Wang, Kun Jia or Zhigang Suo.
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
Reprints and permissions
About this article
Check for updates. Verify currency and authenticity via CrossMark
Cite this article
Wang, Y., Jia, K. & Suo, Z. Non-faradaic junction sensing. Nat Rev Mater (2024). https://doi.org/10.1038/s41578-024-00755-1
Download citation
Accepted:31 October 2024
Published:09 December 2024
DOI:https://doi.org/10.1038/s41578-024-00755-1
Share this article
Anyone you share the following link with will be able to read this content:
Get shareable link
Sorry, a shareable link is not currently available for this article.
Copy to clipboard
Provided by the Springer Nature SharedIt content-sharing initiative