SUPPLEMENTARY INFORMATION. Three-Dimensional Printed Thermal Regulation Textiles

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1 SUPPLEMENTARY INFORMATION Three-Dimensional Printed Thermal Regulation Textiles Tingting Gao 1,, Zhi Yang 2,, Chaoji Chen 1,, Yiju Li 1, Kun Fu 1, Jiaqi Dai 1, Emily M. Hitz 1, Hua Xie 1, Boyang Liu 1, Jianwei Song 1, Bao Yang 2, Liangbing Hu 1, * 1. Department of Materials Science and Engineering, University of Maryland, College Park, Maryland, 20742, USA 2. Department of Mechanical Engineering, University of Maryland, College Park, Maryland, 20742, USA * binghu@umd.edu These authors contributed equally to this work. 1

2 Table of Contents Figure S1. SEM images of the h-bn powders and BNNSs. Figure S2. Raman spectra of the BNNSs, and X-ray diffraction (XRD) profiles of the BN powders and BNNSs. Figure S3. Morphological structure of the BN/PVA fiber before hot-stretching. Figure S4. Elemental mappings of the cross section of the a-bn/pva composite fiber. Figure S5. Profiles of scattering intensity (I q 2 ) as a function of scattering. Figure S6. SEM images of the tensile fractured surface of the a-bn/pva fiber. Figure S7. Schematic illustration of the device for temperature distribution measurement. Figure S8. Schematic illustration of the set-up for thermal conductivity measurement. Supplementary method S1. Textile Temperature Distribution. Supplementary method S2. Thermal Conductivity Measurement. Figure S9. Schematic of hot-drawn process of the fiber. Table S1. Thermal conductivity comparison of our a-bn/pva composite textile with other commercial fabrics. 2

3 Figure S1. SEM images of (a) the h-bn powders and (b) BNNSs. 3

4 Figure S2. (a) Raman spectrum of the h-bn, and (b) X-ray diffraction (XRD) profiles of the h- BN powders and BNNSs. 4

5 Figure S3. Morphological structure of the as-printed BN/PVA fiber before hot stretching. (a) Optical image of the as-printed BN/PVA fiber (Scale bar equals 500 µm). (b) SEM image of the surface section of the BN/PVA fiber. (c) SEM image of the cross section of the BN/PVA fiber. 5

6 Figure S4. Elemental mappings of the cross section of the a-bn/pva composite fiber. 6

7 Figure S5. Profiles of scattering intensity (I q 2 ) as a function of scattering. 7

8 Figure S6. SEM images of the tensile fractured surface of the a-bn/pva fiber. 8

9 Table S1. Thermal conductivity comparison of our a-bn/pva composite textile with other commercial fabrics. Commercial Textiles Thermal conductivity(w/mk) References Wool [1] Silk [2] Jute [3] Polyester [3] Nylon [4] Acrylic [1] BN/PVA composite textile This work References (1) Hashan, M. M., Hasan, K. F., Khandaker, M. F. R., Karmaker, K. C., Deng, Z., & Zilani, M. J. Functional Properties Improvement of Socks Items Using Different Types of Yarn. Int. J. Text. Sci., 2017, 6, (2) Baxter, S. T. The Thermal Conductivity of Textiles. Proc. Phys. Soc., 1946, 58, 105. (3) Manohar, K., Ramlakhan, D., Kochhar, G., & Haldar, S. Biodegradable Fibrous Thermal Insulation. J. Braz. Soc. Mech. Sci. Eng., 2006, 28, (4) Dias, T., & Delkumburewatte, G. B. The Influence of Moisture Content on the Thermal Conductivity of a Knitted Structure. Meas. Sci. Technol., 2007, 18,

10 Supplementary method S1. Textile Temperature Distribution In order to qualitatively identify the in plane thermal dissipation ability for various fabrics, a Laser-IR Camera system were built. As shown in figure S7, the temperature distribution of fabrics was characterized and recorded. A Coherent Highlight FAP 100 laser source with a wavelength of 810 nm was used to provide constant power input to the fabrics as point heat source (spot diameter is around 1 mm) at one side of the fabrics. The heat sink was attached to the other side of fabrics. The temperature distribution of the fabrics was captured using a FLIR Merlin MID IR camera with sensor resolution of 320 x 256 pixels, which detects the IR radiation from um. The in-situ temperature distribution was recorded by ThermaCAM Research software. To ensure accurate temperature readings from IR camera, a calibrated surface emissivity is required, thus a thin layer of graphite coating was applied to each fabric prior to test. As in-plane thermal conductivity varies from fabric to fabric, the maximum local temperature of fabrics will also be different. For a high thermal conductivity fabric, the input power from laser is easily dissipated to the heat sink, which yields lower maximum local temperature at the hot spot. On the contrary, if the fabric suffers from local thermal conductivity, the insufficient heat dissipation from heat source to heat sink will cause heat accumulation around the hot spot, showing a higher maximum local temperature on fabric. Figure S7. Schematic illustration of measuring the temperature distribution when a hotspot is created on the fabric by a focused laser beam. 10

11 Supplementary method S2. Thermal Conductivity Measurement The thermal conductivity was characterized by a system consisting of a laser heat source, two calibrated aluminum blocks, a metal block heat sink and an Infrared Camera. The fabric samples were sandwiched between top and bottom aluminum blocks, as in the above schematic. A Coherent Highlight FAP-1000 (820 nm) laser provided energy input to the system as heat source, and heat sink was used to dissipate heat from the system. The steady state temperature distribution of the fabric sample was captured and recorded by a FLIR Merlin MID Infrared (IR) camera with a resolution of 320 x 256 pixels. Due to the coexistence of multiple heat transfer paths, such as conduction, convection and radiation transfer from heat source to heat sink, a finite element model was built in ANSYS to calculate the thermal conductivity value of fabric. Prior to fabric thermal conductivity measurement, a calibration test was performed using standard material to estimate effective convection and radiation heat transfer coefficient. Then the finite element model was updated with effective convection and radiation heat transfer coefficient for actual fabric thermal conductivity measurement. The thermal conductivity of fabric in ANSYS was tuned until a good temperature gradient was achieved between experimental and numerical simulation results. The thermal conductivities of our samples were all measured under the condition of T = 25 o C and RH = 30-40%. 11

12 Figure S8. Schematic illustration of the set-up for measuring the thermal conductivity of the fabrics. Figure S9. Schematic of hot-drawn process of the fiber. The stretching ratio was controlled by a feeding roll with a low speed (V 0 ) and a stretching reel with a high speed (4 V 0 ). 12