Selective emission fabric for indoor and outdoor passive radiative cooling in personal thermal management
image:
view more
Credit: Haijiao Yu, Jiqing Lu, Jie Yan, Tian Bai, Zhaoxuan Niu, Bin Ye, Wanli Cheng*, Dong Wang*, Siqi Huan*, Guangping Han*.
Radiative-cooling fabrics today pick one battlefield—outdoor sunshade or indoor heat-drain—leaving wearers to swap textiles when they step inside. Now researchers from Northeast Forestry University, led by Prof. Wanli Cheng, Prof. Dong Wang and Prof. Siqi Huan, report a single PVDF-PVP electro-spun fabric whose full-scale micro-/nano-pores reflect 94 % of sunlight while selectively emitting (81 %) and transmitting (25 %) mid-IR heat, realising 60 W m-2 net cooling outdoors and 26 W m-2 indoors—2–4× better than state-of-the-art films.
Why This Fabric Matters
- Dual-Scene Cooling: 94 % solar reflectance blocks outdoor heat; C–F bond vibration in PVDF couples the 8–13 µm atmospheric window to cold sky, while 25 % MIR transmission lets indoor IR escape without sky access—something pure emitters (PDMS) cannot do.
- Full-Scale Structure: 0.6–1.5 µm fibres + 1.5–2.5 µm inter-fibre voids + 20–170 nm semi-interpenetrating pores create triple-length-scale Mie scatterers that reject 0.3–2.5 µm photons but stay transparent to 2.5–25 µm phonons.
- Scalable Process: Single-step electro-spinning of PVDF-PVP (12:6 wt %) followed by 3 h water etch dissolves sacrificial PVP, leaving macropores without compromising mechanical integrity; 220 µm-thick, bright-white, washable and breathable.
Performance & Outlook
- Field Tests (Harbin, 520 W m-2 solar): fabric-covered “skin” 5.5 °C cooler than PDMS film outdoors, 1.4 °C cooler indoors; chocolate melts in 30 min vs 1 min for controls under 4 000 W m-2 xenon light.
- Net Cooling Power: 60 W m⁻² outdoors, 26 W m-2 indoors—highest bi-modal values reported.
- Mechanism: FDTD shows Mie resonance at 0.2–1.2 µm matching fibre-size distribution; newly defined radiation-cooling ratio ℭ = (1 − R) confirms 94 % of non-reflected MIR energy is released.
- Wearable Credentials: Hydrophobic contact angle 128°, tensile strength 12 MPa, air permeability 18 mm s-1, moisture-vapour-transmission-rate 9.5 kg m-2 day-1—meets daily-wear norms.
- Next Steps: laminate onto aramid mesh for >20 MPa tensile strength; 30 cm roll-to-roll pilot line targeted for cooling apparel, tents and vehicle upholstery by late-2025.
By merging selective emission with broadband transmission in one full-scale fibre mat, the work delivers the first “indoor & outdoor” passive-cooling textile—cutting HVAC energy while keeping users comfortable anywhere.