Yongqiang Guo, Shuangshuang Wang, Haitian Zhang, Hua Guo, Mukun He, Kunpeng Ruan, Ze Yu, Guang-sheng Wang*, Hua Qiu and Junwei Gu*. Consistent Thermal Conductivities of Spring-like Structured Polydimethylsiloxane Composites under Large Deformation. Advanced Materials, 2024, 36: 2404648. 2023IF=27.4
https://doi.org/10.1002/adma.202404648
Abstract
Flexible and highly thermally conductive materials with consistent thermal conductivity (λ) during large deformation are urgently required to address the heat accumulation in flexible electronics. In this study, spring-like thermal conduction pathways of silver nanowire (S-AgNW) fabricated by 3D printing are compounded with polydimethylsiloxane (PDMS) to prepare S-AgNW/PDMS composites with excellent and consistent λ during deformation. The S-AgNW/PDMS composites exhibit a λ of 7.63 W m?1 K?1 at an AgNW amount of 20 vol%, which is ≈42 times that of PDMS (0.18 W m?1 K?1) and higher than that of AgNW/PDMS composites with the same amount and random dispersion of AgNW (R-AgNW/PDMS) (5.37 W m?1 K?1). Variations in the λ of 20 vol% S-AgNW/PDMS composites are less than 2% under a deformation of 200% elongation, 50% compression, or 180° bending, which benefits from the large deformation characteristics of S-AgNW. The heat-transfer coefficient (0.29 W cm?2 K?1) of 20 vol% S-AgNW/PDMS composites is ≈1.3 times that of the 20 vol% R-AgNW/PDMS composites, which reduces the temperature of a full-stressed central processing unit by 6.8 °C compared to that using the 20 vol% R-AgNW/PDMS composites as a thermally conductive material in the central processing unit.柔性電子領(lǐng)域的熱量積聚問題使其對大形變下導(dǎo)熱穩(wěn)定的柔性高導(dǎo)熱材料需求迫切。本文采用3D打印技術(shù)制備具有大形變能力的銀納米線螺旋導(dǎo)熱通路（S-AgNW），將其與聚二甲基硅氧烷（PDMS）復(fù)合制備大形變下具有優(yōu)異和穩(wěn)定導(dǎo)熱性能的S-AgNW/PDMS復(fù)合材料。AgNW體積分?jǐn)?shù)為20 vol%的S-AgNW/PDMS復(fù)合材料的導(dǎo)熱系數(shù)（λ）達(dá)7.63 W m-1 K-1，約為純PDMS的λ（0.18 W m-1K-1）的42倍，也遠(yuǎn)高于相同體積分?jǐn)?shù)AgNW在PDMS基體中隨機(jī)分散的R-AgNW/PDMS復(fù)合材料的λ（5.37 W m-1 K-1）。得益于AgNW螺旋導(dǎo)熱通路的大形變特性，20 vol% S-AgNW/PDMS導(dǎo)熱復(fù)合材料在200%伸長率、50%壓縮率和180°彎曲角度等形變下的λ變化率均小于2%。此外，20 vol% S-AgNW/PDMS導(dǎo)熱復(fù)合材料的傳熱系數(shù)（0.29 W cm-2 K-1）約為20 vol% R-AgNW/PDMS導(dǎo)熱復(fù)合材料傳熱系數(shù)（0.22 W cm-2 K-1）的1.3倍，用于CPU散熱時(shí)可使其滿功率工作溫度較20 vol% R-AgNW/PDMS復(fù)合材料作為散熱材料時(shí)的CPU溫度降低6.8oC。
論文亮點(diǎn)
1. 采用3D打印技術(shù)制備具有大形變能力的銀納米線（AgNW）螺旋導(dǎo)熱通路，將其與PDMS復(fù)合制備大形變下具有優(yōu)異和穩(wěn)定導(dǎo)熱性能的S-AgNW/PDMS復(fù)合材料。
2. AgNW體積分?jǐn)?shù)為20 vol%的S-AgNW/PDMS復(fù)合材料的λ達(dá)7.63 W m-1 K-1，約為純PDMS的λ（0.18 W m-1 K-1）的42倍，其在200%伸長率、50%壓縮率和180°彎曲角度等形變下的λ變化率均小于2%。
3. 掃描電子顯微鏡和微納尺度熱傳導(dǎo)模擬表明，AgNW螺旋導(dǎo)熱通路的大形變特性使AgNW在S-AgNW/PDMS導(dǎo)熱復(fù)合材料形變時(shí)發(fā)生的位移變化很小，不影響整體的熱傳導(dǎo)過程。
作者：郭永強(qiáng)郵件地址：gyqnpu@nwpu.edu.cn
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