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Radiative human body cooling by nanoporous polyethylene textile

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Science  02 Sep 2016:
Vol. 353, Issue 6303, pp. 1019-1023
DOI: 10.1126/science.aaf5471
  • Fig. 1 Optical property and morphology of nanoPE.

    (A) Simulated air conditioner setpoint as the function of IR transmittance of textile at constant human skin temperature and metabolic generation rate. (B) Schematics of comparison between nanoPE, normal PE, and cotton. Only nanoPE satisfies IR transparency, visible light opacity, and air convection simultaneously. (C) Simulated total and specular transmittance of infrared and visible light for nanoPE, with average pore size of 400 nm. The thickness of nanoPE is 12 μm. Human body radiation is indicated by the yellow shaded region. (D) Simulated weighted average transmittance based on human body radiation for various pore sizes. The average transmittance drops from >90% to 80% as the pore size increases and begin to affect the transmission of human body radiation. (E) Photo of commercial nanoPE. (F) High-resolution SEM images of nanoPE. The nanopores are only 50 to 1000 nm in diameter, which is essential to ensure high IR transmittance. (G) Measured total FTIR transmittance of nanoPE, normal PE, and cotton. Because of the small pore size, nanoPE is as transparent as normal PE. Cotton, on the other hand, is completely opaque. (H) Visible opacity measurement quantitatively confirms that nanoPE is as opaque as cotton.

  • Fig. 2 Thermal measurement of nanoPE and various textile samples.

    (A) Experimental setup of textile thermal measurement. The heating element that generates constant heating power is used to simulate human skin, and the “skin temperature” is measured with the thermocouple. Lower skin temperature means a better cooling effect. (B) Thermal measurement of bare skin, nanoPE, cotton, and Tyvek. NanoPE has a much better cooling effect than that of cotton and Tyvek because of its high IR-transparency. (C) Thermal imaging of bare skin and the three samples. Only nanoPE can reveal the H-shape metallic pattern because of its IR-transparency.

  • Fig. 3 The treatment of nanoPE for various wearability testing.

    (A) Schematic of the fabrication process of PDA-nanoPE-mesh. In all the textile tests, PDA-nanoPE-mesh shows performance comparable with that of cotton. (B) Water vapor transmission rate test shows how human perspiration can transmit through the textile. (C) Air permeability test examines the air flow rate through the textile at certain pressure drops. (D) Wicking distance shows the ability to transport perspiration for quick evaporation. (E) Tensile strength test demonstrates that PDA-nanoPE-mesh has the same ultimate tensile strength as that of cotton.

  • Fig. 4 Properties of PDA-nanoPE-mesh.

    (A) Photo of PDA-nanoPE-mesh. The spots that are 1 mm in diameter are the welding points. The microholes for improving air permeability are barely noticeable. (B) Total IR transmittance. (C) Visible opacity. (D) Thermal measurement.

Supplementary Materials

  • Radiative human body cooling by nanoporous polyethylene textile

    Po-Chun Hsu, Alex Y. Song, Peter B. Catrysse, Chong Liu, Yucan Peng, Jin Xie, Shanhui Fan, Yi Cui

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S8
    • Table S1
    • Full Reference List

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