Liquid-Metal-Enabled, Bifunctional Core-Sheath Metafibers for Sensitive Biomotion Sensing and Radiative Personal Thermal Management

Abstract

Combining radiative cooling with electronic sensing is crucial for the next generation of adaptive wearables. However, it remains challenging to achieve both efficient optical–thermal regulation and highly sensitive biomotion-sensing fiber architectures. Here, we develop porous core-sheath fibers that utilize the dual effects of liquid metal (LM) to integrate motion sensing and passive radiative cooling functions in a single fiber. The encapsulated LM microdroplets within the polymer act as both reconfigurable conductive networks and optical–thermal modulation units. These fibers exhibit excellent mechanical robustness, with an elongation at break exceeding 1000%. Owing to the piezoresistive LM network, the fibers exhibit sensing performance, featuring a strain detection limit of 0.01%, a response time of 62 ms, and a durability over 20000 cycles. Meanwhile, LM microdroplets serve dual roles as microscale reflectors and efficient heat transfer media. The synergistic effect between the porous polymer and LM microdroplets endows the fabrics with excellent radiative cooling capabilities, achieving a solar reflectance of 95.3% and a mid-infrared emissivity of 96.1%. Outdoor tests show the sustained subambient cooling of 5.2–6.3 °C and annual energy saving of 80–320 MJ/m² year⁻¹. Furthermore, these fibers enable simultaneous real-time gesture recognition and personal thermal management, thereby providing a versatile platform for multifunctional smart textiles.

Keywords

Liquid metal / Coaxial wet spinning / Radiative cooling / Biomotion sensing / Smart wearables

References

[1] Xu J, Xie W, Han H, Xiao C, Li J, Zhang Y, Chen S, Zhao B, Zhang D, Zhou HRadiative cooling materials for extreme environmental applications. Nano Micro Lett, 2025, 17: 324.

[2] Cima MJNext-generation wearable electronics. Nat Biotechnol, 2014, 32642-643.

[3] Yu RH, Wang CX, Du XH, Bai XW, Tong YZ, Chen HF, Sun XM, Yang J, Matsuhisa N, Peng HS, Zhu MF, Pan SWIn-situ forming ultra-mechanically sensitive materials for high-sensitivity stretchable fiber strain sensors. Nat Sci Rev, 2024, 11: nwae158.

[4] Tang Y, Fu H, Xu BAdvanced design of triboelectric nanogenerators for future eco-smart cities. Adv Compos Hybrid Mater, 2024, 7102.

[5] Li J, Xu BNovel highly sensitive and wearable pressure sensors from conductive three-dimensional fabric structures. Smart Mater Struct, 2015, 24125022

[6] Lee M, Kim G, Jung Y, Pyun KR, Lee J, Kim B-W, Ko SHPhotonic structures in radiative cooling. Light Sci Appl, 2023, 12134.

[7] Feyisa T, Belay A, Tolessa F, Kudishe K, Sherefedin U, Gelanu D, Haji J, Golja DR, Zityab MOptimizing thermal radiation control with ultra-broadband metamaterials for high passive radiative cooling efficiency. Sci Rep, 2025, 1543150.

[8] Gao Z, Wang Y, Pan Y, Ma J, Liu X, Liu C, Shen CMoisture-wicking fabric for radiation cooling. Nano Res, 2025, 1894907537

[9] Cataldi P, Steiner P, Liu M, Pinter G, Athanassiou A, Kocabas C, Kinloch IA, Bissett MAA green electrically conductive textile with tunable piezoresistivity and transiency. Adv Funct Mater, 2023, 332301542

[10] Yang Y, Liu Y, Yin RFiber/yarn and textile-based piezoresistive pressure sensors. Adv Fiber Mater, 2025, 734-71.

[11] Yu R, Wu L, Yang Z, Wu J, Chen H, Pan S, Zhu MDynamic liquid metal–microfiber interlocking enables highly conductive and strain-insensitive metastructured fibers for wearable electronics. Adv Mater, 2025, 372415268

[12] Dang C, Wang Z, Hughes-Riley T, Dias T, Qian S, Wang Z, Wang X, Liu M, Yu S, Liu R, Xu D, Wei L, Yan W, Zhu MFibres—threads of intelligence—enable a new generation of wearable systems. Chem Soc Rev, 2024, 53: 8790-8846.

[13] Fu W, Yu B, Ji D, Zhou Z, Li X, Wang R, Lu W, Sun Y, Dai YIntelligent fibers and textiles for wearable biosensors. Respons Mater, 2024, 2e20240018

[14] Zhu Z, Bashir A, Wu X, Liu C, Zhang Y, Chen N, Li Z, Chen Y, Ouyang X, Chen D-ZHighly integrated phase change and radiative cooling fiber membrane for adaptive personal thermal regulation. Adv Funct Mater, 2025, 352416111

[15] Xu T, Yeow Seow JZ, Tan S, Li S, Chen T, Ji G, Xu ZJRadiative smart fibers and textiles: thermal management and beyond. ACS Nano, 2025, 19: 32995-33007.

[16] Cui T, Zheng Y, Cai W, Qi L, Wang J, Yang W, Song W, Hu Y, Zhu JQuantum to device AI-guided passivation paradigm for all-weather ultrastable MXene based photothermal converter. Adv Mater, 2026, 38e19482

[17] Tan D, Xu B, Gao Y, Tang Y, Liu Y, Yang Y, Li ZBreathable fabric-based triboelectric nanogenerators with open-porous architected polydimethylsiloxane coating for wearable applications. Nano Energy, 2022, 104107873

[18] Liu X, Zhang W, Zhang X, Zhou Z, Wang C, Pan Y, Hu B, Liu C, Pan C, Shen CTransparent ultrahigh-molecular-weight polyethylene/MXene films with efficient UV-absorption for thermal management. Nat Commun, 2024, 153076

[19] Zhang Y, Zhang Y, Zhou J, Zhang D, Lin H, Chen Y, Li Y, Xiong JStretchable composite conductive fibers for wearables. Adv Mater Technol, 2023, 8: 2201442.

[20] Chung KY, Tan D, He Z, Li X, Lu J, Yang Q, Liu X, Xu BCottonseed-derived reusable bio-carbon gel ink for DIW printing soft electronic textiles. Adv Mater, 2025, 372415702

[21] Liu H, Zhang S, Li Z, Lu TJ, Lin H, Zhu Y, Ahadian S, Emaminejad S, Dokmeci MR, Xu F, Khademhosseini AHarnessing the wide-range strain sensitivity of bilayered PEDOT:PSS films for wearable health monitoring. Matter, 2021, 42886-2901.

[22] Zheng L, Zhu M, Wu B, Li Z, Sun S, Wu PConductance-stable liquid metal sheath-core microfibers for stretchy smart fabrics and self-powered sensing. Sci Adv, 2021, 7eabg4041

[23] Liu J, Ji B, Zhong Y, Zhang L, Wang B, Feng X, Xu H, Mao ZPhotoluminescent core–shell structural porous fibers-based metafabric for colored daytime passive radiative cooling. ACS Nano, 2025, 19: 10263-10276.

[24] Chung KY, Xu B, Tan D, Yang Q, Li Z, Fu HNaturally crosslinked biocompatible carbonaceous liquid metal aqueous ink printing wearable electronics for multi-sensing and energy harvesting. Nano Micro Lett, 2024, 16: 149.

[25] Zhao Z, Soni S, Lee T, Nijhuis CA, Xiang DSmart eutectic gallium–indium: from properties to applications. Adv Mater, 2023, 352203391

[26] Zhang Y, Zhu H, An S, Xing W, Fu B, Tao P, Shang W, Wu J, Dickey MD, Song C, Deng TChameleon-inspired tunable multi-layered infrared-modulating system via stretchable liquid metal microdroplets in elastomer film. Nat Commun, 2024, 155395.

[27] Lathia R, Nagpal S, Modak CD, Mishra S, Sharma D, Reddy BS, Nukala P, Bhat R, Sen PTunable encapsulation of sessile droplets with solid and liquid shells. Nat Commun, 2023, 146445.

[28] Luo M, Wei W, Guo Q, Zhong W, Jia K, Chang K, Lu Y, Li M, Wang DA liquid metal-embedded sheath-core fiber with internal helical structure for strain-insensitive electronics. Adv Sci, 2025, 12e09547

[29] Li Q, Liu L, Lin M, Guo X, Guan L, Liu Z, Li R, Zhu Y, Zhao B, Zhang RHighly conductive sheath–core structured liquid metal fibers with invariant resistance under high tensile strength. Appl Mater Today, 2025, 42102620

[30] An Z, Fu Q, Lv J, Zhou T, Wu Y, Lu Y, Liu G, Shi Z, li X, Zhang F, Liu QBody heat powered wirelessly wearable system for real-time physiological and biochemical monitoring. Adv Funct Mater, 2023, 332303361

[31] Liu Y, Zhang W, Wang HSynthesis and application of core–shell liquid metal particles: a perspective of surface engineering. Mater Horiz, 2021, 856-77.

[32] Hu X, Quan B, Shi Z, Zhao X, Lu G, Ding Y, Lai J, Qu J, Peng Y, Lu XBioinspired hierarchical radiative-phase change hybrid cooling composite with record-breaking cooling power. Adv Mater, 2025, 38e10988

[33] Hu W, Zhang F, Tan X, Tu Y, Nie SAntibacterial PVDF coral-like hierarchical structure composite film fabrication for self-cleaning and radiative cooling effect. ACS Appl Mater Interfaces, 2024, 16: 19828-19837.

[34] Lee S, Park J-S, Lee TRThe wettability of fluoropolymer surfaces: influence of surface dipoles. Langmuir, 2008, 24: 4817-4826.

[35] Pinho AC, Piedade APAdditive manufacturing of TPU/C and PVDF/graphene composites with adjustable mechanical and conductive properties for sensor applications. Results Eng, 2025, 27105760

[36] Handschuh-Wang S, Zhu L, Gan T, Wang T, Wang B, Zhou XInterfacing of surfaces with gallium-based liquid metals – approaches for mitigation and augmentation of liquid metal adhesion on surfaces. Appl Mater Today, 2020, 21100868

[37] Ding Y, Zeng M, Fu LSurface chemistry of gallium-based liquid metals. Matter, 2020, 3: 1477-1506.

[38] Bao H, Ma Y, Sun J, Zhao Q, Yang L, Hou Y, He H, Huang H, Ji H, Qiu JFlexible and transparent ionic liquids/Poly(vinylidene fluoride) composition-gradient piezo-active composites for highly sensitive pressure sensor. Adv Electron Mater, 2023, 9: 2201013.

[39] Begum S, Ullah H, Ahmed I, Zhan Y, Kausar A, Aleem MA, Ahmad SInvestigation of morphology, crystallinity, thermal stability, piezoelectricity and conductivity of PVDF nanocomposites reinforced with epoxy functionalized MWCNTs. Compos Sci Technol, 2021, 211108841

[40] Li X, Li M, Xu J, You J, Yang Z, Li CEvaporation-induced sintering of liquid metal droplets with biological nanofibrils for flexible conductivity and responsive actuation. Nat Commun, 2019, 103514.

[41] Rehwoldt MC, Wang Y, Xu F, Ghildiyal P, Zachariah MRHigh-temperature interactions of metal oxides and a PVDF binder. ACS Appl Mater Interfaces, 2022, 148938-8946.

[42] Zhu S, So J-H, Mays R, Desai S, Barnes WR, Pourdeyhimi B, Dickey MDUltrastretchable fibers with metallic conductivity using a liquid metal alloy core. Adv Funct Mater, 2013, 23: 2308-2314.

[43] Laperrousaz S, Chen X, Cleusix M, Jourdan L, Tribolet L, Sorin FElectronic fibres via the thermal drawing of liquid-metal-embedded elastomers. Nat Electron, 2025, 8: 1072-1081.

[44] Feng M, Cai H, Feng S, Liu Y, Li Z, He X, Liang S, Bu X, Huang J, Zhou YAsymmetric gradient porous fabric with dynamically tunable thermal management and electromagnetic interference shielding via delayed phase separation. Adv Funct Mater, 2025, 352422487

[45] Sun F, Tian M, Sun X, Xu T, Liu X, Zhu S, Zhang X, Qu LStretchable conductive fibers of ultrahigh tensile strain and stable conductance enabled by a worm-shaped graphene microlayer. Nano Lett, 2019, 19: 6592-6599.

[46] Liu ZF, Fang S, Moura FA, Ding JN, Jiang N, Di J, Zhang M, Lepró X, Galvão DS, Haines CS, Yuan NY, Yin SG, Lee DW, Wang R, Wang HY, Lv W, Dong C, Zhang RC, Chen MJ, Yin Q, Chong YT, Zhang R, Wang X, Lima MD, Ovalle-Robles R, Qian D, Lu H, Baughman RHHierarchically buckled sheath-core fibers for superelastic electronics, sensors, and muscles. Science, 2015, 349: 400-404.

[47] Qu Y, Nguyen-Dang T, Page AG, Yan W, Das Gupta T, Rotaru GM, Rossi RM, Favrod VD, Bartolomei N, Sorin FSuperelastic multimaterial electronic and photonic fibers and devices via thermal drawing. Adv Mater, 2018, 301707251

[48] Zhang Z, Deng J, Li X, Yang Z, He S, Chen X, Guan G, Ren J, Peng HSuperelastic supercapacitors with high performances during stretching. Adv Mater, 2015, 27: 356-362.

[49] Zhou J, Tian G, Jin G, Xin Y, Tao R, Lubineau GBuckled conductive polymer ribbons in elastomer channels as stretchable fiber conductor. Adv Funct Mater, 2020, 301907316

[50] Zhao Y, Dong D, Gong S, Brassart L, Wang Y, An T, Cheng WA moss-inspired electroless gold-coating strategy toward stretchable fiber conductors by dry spinning. Adv Electron Mater, 2019, 5: 1800462.

[51] Yamada T, Hayamizu Y, Yamamoto Y, Yomogida Y, Izadi-Najafabadi A, Futaba DN, Hata KA stretchable carbon nanotube strain sensor for human-motion detection. Nat Nanotechnol, 2011, 6296-301.

[52] Li Y, Xiong J, Lv J, Chen J, Gao D, Zhang X, Lee PSMechanically interlocked stretchable nanofibers for multifunctional wearable triboelectric nanogenerator. Nano Energy, 2020, 78105358

[53] Fan C, Long Z, Zhang Y, Mensah A, He H, Wei Q, Lv PRobust integration of energy harvesting with daytime radiative cooling enables wearing thermal comfort self-powered electronic devices. Nano Energy, 2023, 116108842

[54] Mandal J, Fu Y, Overvig AC, Jia M, Sun K, Shi NN, Zhou H, Xiao X, Yu N, Yang YHierarchically porous polymer coatings for highly efficient passive daytime radiative cooling. Science, 2018, 362: 315-319.

[55] Chen H, Xie Y, Qiao K, Xie L, Yu Z, Xu C, Liu J, Liu M, Lu Y, Liu J, Hu F, Shen B, Chu K, Law JY, Franco V, Zhang HThermomagnetic liquid metal switches with fast bidirectional response. Nat Commun, 2025, 16: 2634.

[56] Cao C, Gu J, Zhu W, Li H, Liu R, Zhang W, Li R, Li D, Ling J, Ge M, Wang X, Yao X, Fei BHighly adhesive liquid metal interface-enabled stretchable bioelectronics with enhanced radiative cooling for wound management. Adv Funct Mater, 2026, 36e16990

[57] Yao S, Guo H, Han Q, Li C, Li P, Yang Z, Sun X, Zhao C, Peng H, Wang BPassive cooling fabrics with tailored cracked structures for personal indoor thermal-humidity management. Adv Mater Technol, 2025, 10e00428

[58] Peng Y, Liu H, Huang H, Long J, Dong J, Weng M, Wang J, Liu T, Huang YSynergistic radiative-evaporative cooling and high-fidelity sweat sensing via liquid metal-integrated janus textiles. Adv Funct Mater, 2026, 36e75085

[59] Fu J-H, Zhang Q, Yan M, Tang W, Zeng Y, Cui Y, Zhang M, Deng H, Kang H, Sun X, Qiao L, Wang H, Zhao YA flexible and superhydrophobic PVDF-HFP@PVA bilayer enables high-performance radiative cooling and thermal management. Chem Eng J, 2024, 502157877

[60] Zeng S, Pian S, Su M, Wang Z, Wu M, Liu X, Chen M, Xiang Y, Wu J, Zhang M, Cen Q, Tang Y, Zhou X, Huang Z, Wang R, Tunuhe A, Sun X, Xia Z, Tian M, Chen M, Ma X, Yang L, Zhou J, Zhou H, Yang Q, Li X, Ma Y, Tao GHierarchical-morphology metafabric for scalable passive daytime radiative cooling. Science, 2021, 373692-696.

[61] He J, Zhang Q, Zhou Y, Chen Y, Ge H, Tang SBioinspired polymer films with surface ordered pyramid arrays and 3D hierarchical pores for enhanced passive radiative cooling. ACS Nano, 2024, 18: 11120-11129.

[62] Zhang Y, Fu J, Ding Y, Babar AA, Song X, Chen F, Yu X, Zheng ZThermal and moisture managing E-textiles enabled by janus hierarchical gradient honeycombs. Adv Mater, 2024, 36: 2311633.

[63] Yang M, Zhong H, Li T, Wu B, Wang Z, Sun DPhase change material enhanced radiative cooler for temperature-adaptive thermal regulation. ACS Nano, 2023, 171693-1700.

[64] Wang K, Luo G, Guo X, Li S, Liu Z, Yang CRadiative cooling of commercial silicon solar cells using a pyramid-textured PDMS film. Sol Energy, 2021, 225: 245-251.

[65] Zhao H, Sun Q, Zhou J, Deng X, Cui JSwitchable cavitation in silicone coatings for energy-saving cooling and heating. Adv Mater, 2020, 322000870

[66] Li T, Zhai Y, He S, Gan W, Wei Z, Heidarinejad M, Dalgo D, Mi R, Zhao X, Song J, Dai J, Chen C, Aili A, Vellore A, Martini A, Yang R, Srebric J, Yin X, Hu LA radiative cooling structural material. Science, 2019, 364: 760-763.

[67] Chai J, Wang G, Wang G, Shao R, Zhao J, Zhao G, Park CBPorous and conductive fiber woven textile for multi-functional protection, personal warmth, and intelligent motion/temperature perception. Adv Funct Mater, 2025, 352416428.

[68] Pan QH, Wang MH, Huang ZY, Qiu XJ, Wang YT, Zhao FX, Zhu MH, Guo X, Chen C, Zhang SC, Wang JL, He Z, Yu SHBiomimetic pyramid structure film for enhancing building radiative cooling. Adv Sci, 2025, 122413559

Funding

Hong Kong Polytechnic University(1-CDPF)

The Hong Kong Polytechnic University

Rights & permissions

The Author(s)