Hierarchical Wool-Decorated Fiber Sensors with Minimizing Cross-talk for Multimodal Perception of Strain, Pressure, and Temperature Channels for Next-Generation Smart Textiles

Abstract

Hierarchically structured fiber sensors capable of multimodal, reduced cross-talk detection of strain, pressure, and temperature are highly desirable for smart textiles, yet remain challenging to realize within a single textile-friendly architecture. Here, a wool-decorated multimodal fiber sensor (WDMFS) is reported that integrates piezoresistive (PR), piezocapacitive (PC), and thermoresistive channels along a coaxial fiber comprising a silver-embedded polyurethane core, a liquid metal (LM) shell, and an outer Ag‑embedded fine‑wool sheath that serves as a textile‑like interface. The PR channel provides nearly hysteresis-free strain sensing up to 110% with a gauge factor of 0.77%⁻¹ and demonstrates stable operation over 2500 cycles. The PC channel exhibits a pressure sensitivity of 0.002 kPa⁻¹ over 0–100 kPa with millisecond-scale response and recovery times, and the thermoresistive channel shows a sensitivity of 0.0004 °C⁻¹ with linear response between 10 and 80 °C. Within this hierarchical architecture, the PR channel is responsive to tensile strain, the PC channel is sensitive to normal pressure, and the LM thermoresistive channel tracks temperature variations, this selective channel responsiveness minimizes signal overlap and thereby enables multimodal sensing with reduced cross-talk. Beyond enabling multimodal transduction, the fine‑wool sheath further enhances breathability and sewability by mitigating the tackiness of elastomer encapsulation, enabling integration into fabrics for joint motion monitoring or respiration sensing, thereby establishing the WDMFS as a promising building block for next-generation wearable electronics and smart textiles.

Graphical Abstract

Keywords

Multimodal fiber sensor / Hierarchical structure / Piezoresistive strain sensor / Piezocapacitive pressure sensor / Thermoresistive temperature sensor / Sew-ability

References

[1] Heo JS, Hossain MF, Kim I. Challenges in design and fabrication of flexible/stretchable carbon- and textile-based wearable sensors for health monitoring: a critical review. Sensors, 2020, 20: 3927

[2] Li S, Li H, Lu Y, Zhou M, Jiang S, Du X, Guo C. Advanced textile-based wearable biosensors for healthcare monitoring. Biosensors, 2023, 13: 909

[3] Azeem M, Shahid M, Masin I, Petru M. Design and development of textile-based wearable sensors for real-time biomedical monitoring: a review. J Text Inst, 2025, 116: 80

[4] Lee KP, Yip J, Yick KL, Lu C, Lo CK. Textile-based fiber optic sensors for health monitoring: a systematic and citation network analysis review. Text Res J, 2022, 92: 2922

[5] Zhou Z, Chen N, Zhong H, Zhang W, Zhang Y, Yin X, He B. Textile-based mechanical sensors a review. Materials, 2021, 14: 6073

[6] Akter A, Apu MM, Veeranki YR, Baroud TN, Posada-Quintero HF. Recent studies on smart textile-based wearable sweat sensors for medical monitoring: a systematic review. J Sens Actuator Netw, 2024, 13: 40

[7] Zhong W, Ming X, Li W, Jia K, Jiang H, Ke Y, Li M, Wang D. Wearable human-machine interaction device integrated by all-textile-based tactile sensors array via facile cross-stitch. Sens Actuators A, 2022, 333 113240

[8] Liao X, Song W, Zhang X, Huang H, Wang Y, Zheng Y. Directly printed wearable electronic sensing textiles towards human–machine interfaces. J Mater Chem C, 2018, 6: 12841

[9] He Q, Wu Y, Feng Z, Fan W, Lin Z, Sun C, Zhou Z, Meng K, Wu W, Yang J. An all-textile triboelectric sensor for wearable teleoperated human–machine interaction. J Mater Chem A, 2019, 7: 26804

[10] Zhou Z, Li Y, Cheng J, Chen S, Hu R, Yan X, Liao X, Xu C, Yu J, Li L. Supersensitive all-fabric pressure sensors using printed textile electrode arrays for human motion monitoring and human–machine interaction. J Mater Chem C, 2018, 6: 13120

[11] Tchantchane R, Zhou H, Zhang S, Dunn A, Sariyildiz E, Alici G. Advancing human–machine interface (HMI) through development of a conductive-textile based capacitive sensor. Adv Mater Technol, 2025, 10: 2401458

[12] Zhang L, He J, Liao Y, Zeng X, Qiu N, Liang Y, Xiao P, Chen T. A self-protective, reproducible textile sensor with high performance towards human–machine interactions. J Mater Chem A, 2019, 7: 26631

[13] Islam GN, Ali A, Collie S. Textile sensors for wearable applications: a comprehensive review. Cellulose, 2020, 27: 6103

[14] Zhang JW, Zhang Y, Li YY, Wang P. Textile-based flexible pressure sensors: a review. Polym Rev, 2022, 62: 65

[15] Yang Y, Liu Y, Yin R. Fiber/yarn and textile-based piezoresistive pressure sensors. Adv Fiber Mater, 2025, 7: 34

[16] Choudhry NA, Rasheed A, Ahmad S, Arnold L, Wang L. Design, development and characterization of textile stitch-based piezoresistive sensors for wearable monitoring. IEEE Sens J, 2020, 20: 10485

[17] Seo J, Li S, Tsogbayar D, Hwang T, Park J, Ko E, Park SJ, Yang C, Lee HS. Advanced multiparallel-connected piezoresistive physical sensors: elevating performance reliability of flexible strain and pressure sensors. ACS Appl Mater Interfaces, 2024, 16: 22229

[18] Khan A, Rashid M, Hossain G. Industrially scalable piezoresistive smart-textile sensor for flexible electronics application. ACS Sens, 2023, 8: 4801

[19] Kaur G, Meena JS, Jassal M, Agrawal AK. Hybrid piezo-capacitive multimodal sensors based on polyurethane–poly(vinylidene fluoride) nanofibers for wearable e-textiles. ACS Appl Electron Mater, 2023, 5: 3298

[20] Su M, Li P, Liu X, Wei D, Yang J. Textile-based flexible capacitive pressure sensors: a review. Nanomaterials, 2022, 12: 1495

[21] Zhang Q, Wang YL, Xia Y, Kirk TV, Chen XD. Textile-only capacitive sensors with a lockstitch structure for facile integration in any areas of a fabric. ACS Sens, 2020, 5: 1535

[22] Wan X, Cong H, Jiang G, Liang X, Liu L, He H. A review on PVDF nanofibers in textiles for flexible piezoelectric sensors. ACS Appl Nano Mater, 2023, 6: 1522

[23] Maestri G, Ferreira LB, Bachmann P, Paim AA, Merlini C, Steffens F. Recent advances in piezoelectric textile materials: a brief literature review. J Eng Fibers Fabr, 2023, 18: 15589250231151242

[24] Zheng Y, Liu H, Chen X, Qiu Y, Zhang K. Wearable thermoelectric-powered textile-based temperature and pressure dual-mode sensor arrays. Org Electron, 2022, 106 106535

[25] Li M, Chen J, Zhong W, Luo M, Wang W, Qing X, Lu Y, Liu Q, Liu K, Wang Y, Wang D. Large-area, wearable, self-powered pressure–temperature sensor based on 3D thermoelectric spacer fabric. ACS Sens, 2020, 5: 2545

[26] Ha H, Suryaprabha T, Choi C, Chandio ZA, Kim B, Lim S, Cheong JY, Hwang B. Recent research trends in textile-based temperature sensors: a mini review. Nanotechnology, 2023, 34 422001

[27] Soomro AM, Jawed B, Qayoom A, Hyder H, Hussain K, Iram L, Waqas M, Ahmed F, Sattar A, Almani S, Lim JH. Textile-based flexible temperature sensors for wearable and sports applications. Phys Status Solidi A, 2024, 221: 2300523

[28] Li J, Fang L, Sun B, Li X, Kang SH. Recent progress in flexible and stretchable piezoresistive sensors and their applications. J Electrochem Soc, 2020, 167 037561

[29] Nguyen T, Dinh T, Phan HP, Pham TA, Dau VT, Nguyen NT, Dao DV. Advances in ultrasensitive piezoresistive sensors: from conventional to flexible and stretchable applications. Mater Horiz, 2021, 8: 2123

[30] Baek S, Jang H, Kim SY, Jeong H, Han S, Jang Y, Kim DH, Lee HS. Flexible piezocapacitive sensors based on wrinkled microstructures: toward low-cost fabrication of pressure sensors over large areas. RSC Adv, 2017, 7: 39420

[31] Su D, Jiang L, Pan Z, Yang C, Liu C, Liu R, Liu T, He X, Huang S, Cheng Z. Ultrasensitive, signal-complementary piezo-capacitive pressure sensor for complex physiological monitoring and HMI. Chem Eng J, 2025

[32] Kim SR, Kim JH, Park JW. Wearable and transparent capacitive strain sensor with high sensitivity based on patterned Ag nanowire networks. ACS Appl Mater Interfaces, 2017, 9: 26407

[33] Guo K, Liu J, Gong N, Li Y, Guo Q. Flexible fiber-based multimodal perception system with integrated pressure, humidity, and temperature sensing for wearable application. Chem Eng J, 2025, 506 159925

[34] Peng Y, Dong J, Sun J, Mao Y, Zhang Y, Long J, Li L, Zhang C, Zhao Y, Lu H, Qian HL. Multimodal health monitoring via a hierarchical and ultrastretchable all-in-one electronic textile. Nano Energy, 2023, 110 108374

[35] Hwang T, Tsogbayar D, Choi HH, Lee HS. Next-generation wearable sensors: toward multi-directional strain sensing in sensory integration platforms. J Mater Chem C, 2024, 12: 15310

[36] Gautschi G. Piezoelectric sensors. In: Piezoelectric Sensorics: Force, Strain, Pressure, Acceleration and Acoustic Emission Sensors, Materials and Amplifiers. Springer Berlin Heidelberg, Berlin, Heidelberg. 2002. 73.

[37] Dinh T, Phan HP, Qamar A, Woodfield P, Nguyen NT, Dao DV. Thermoresistive effect for advanced thermal sensors: fundamentals, design considerations, and applications. J Microelectromech Syst, 2017, 26: 966

[38] Klösel K, Roman C, Hierold C. thermoelectric and thermoresistive effect in bise : a novel dual-mode temperature and heat flux sensor. J Microelectromech Syst, 2023, 32: 445

[39] Bai J, Gu W, Bai Y, Li Y, Yang L, Fu L, Li S, Li T, Zhang T. Multifunctional flexible sensor based on PU-TA@MXene Janus architecture for selective direction recognition. Adv Mater, 2023, 35 2302847

[40] Wu X, Han Y, Zhang X, Lu C. Highly sensitive, stretchable, and wash-durable strain sensor based on ultrathin conductive layer@polyurethane yarn for tiny motion monitoring. ACS Appl Mater Interfaces, 2016, 8: 9936

[41] Tsogbayar D, Seo J, Hwang T, Park J, Ko E, Kim Y, Yoon CM, Lee HS. Advanced flexible physical sensors with independent detection mechanisms of pressure and strain stimuli for overcoming signal interference. ACS Appl Mater Interfaces, 2024, 16: 49574

[42] Tsogbayar D, Seo J, Hwang T, Kim Y, Park J, Oh S, Xu W, Lee HS. Multimodal double-helix fiber sensors for distinguishable pressure and strain detection in wearable sensory applications. ACS Appl Mater Interfaces, 2025, 17: 62410

[43] Li S, Hwang T, Seo J, Ko E, Tsogbayar D, Khan MR, Lee HS. An effective methodology for achieving highly reliable physical sensors with high sensitivity and low hysteresis through parallel-structured piezoresistors. Adv Mater Technol, 2023, 8: 2201773

[44] Zhang L, Wei Q, Ye L, Wu Z, Huang Y, Yu C, Li Z, Lu S. A flexible multifunctional sensor based on in situ reduction of Ag nanoparticles by yam polysaccharides. Int J Biol Macromol, 2025, 306 141541

[45] Liu E, Cai Z, Ye Y, Zhou M, Liao H, Yi Y. An overview of flexible sensors: development, application, and challenges. Sensors, 2023, 23: 817

[46] Wang L, Fu X, He J, Shi X, Chen T, Chen P, Wang B, Peng H. Application challenges in fiber and textile electronics. Adv Mater, 2020, 32: 1901971

[47] Yin L, Sun X. Textile-based sensors for human motion sensing: recent developments and future perspectives. Nanocomposites, 2025, 11: 79

[48] Liu X, Miao J, Fan Q, Zhang W, Zuo X, Tian M, Zhu S, Zhang X, Qu L. Recent progress on smart fiber and textile-based wearable strain sensors: materials, fabrications and applications. Adv Fiber Mater, 2022, 4: 361

[49] Wu W. Anti-crosstalk materials and structural decoupling strategies for multimodal flexible sensors. Adv Funct Mater, 2026, 36 e24222

RIGHTS & PERMISSIONS

The Author(s)