纳米银线-环氧树脂复合导电薄膜的制备及其在柔性触控上的应用

纳米银线透明导电薄膜具有优异的光电性能和机械性能,有望取代传统的氧化铟锡材料应用于柔性光电器件中。为解决纳米银线的黏附性、柔韧性和稳定性问题,结合转印法和烷基硫醇修饰法制备了纳米银线-环氧树脂复合导电薄膜。在此过程中,首先应用十八烷基三氯硅烷对转移衬底进行疏水化处理以提升透明电极转印的良率;接着,对转印后的纳米银线进行烷基硫醇分子的自组装修饰,以进一步提升纳米银线透明导电薄膜的稳定性;最后在此基础上制备了柔性投射式电容触控屏。所制备的透明导电薄膜具有优异的综合性能:品质因数约为300(Rs=29.7Ω/□,T=96.2%);薄膜经过100次胶带测试后,电阻变化小于25%;在1 000次弯曲(弯曲半径为1mm)测试后,电阻几乎不发生变化;高温高湿下老化一个月,电阻变化小于20%。本文结合转印工艺以及分子修饰技术开发的纳米银线-环氧树脂复合导电薄膜以及柔性触控工艺,有望推广应用至其他柔性电子元件中。

Fabrication of AgNWs-epoxy composite film and its application in flexible touch panel

Silver nanowires (AgNWs) are regarded as one of the promising alternatives to traditional indium tin oxide as transparent conductive materials because of its outstanding opto-electronic and mechanical performances. In order to improve the adhesion, flexibility and stability of AgNWs films, we proposed a facile transferring and alkanethiolate based self-assembled process to fabricate the AgNWs-epoxy resin (EPR) composite film. Firstly, surface energy of the temporary substrate was modified by trichloro(octadecyl)silane to facilitate the delamination from EPR. Then the AgNWs-EPR composite film was further decorated by methyl-terminated alkanethiolate for better stability. Finally, a flexible projective capacitive touch panel enabling multi-touch was fabricated by this composite film. The AgNWs-EPR composite film capped with alkanethiolate monolayers exhibited comprehensive performance including high FoM of 300 (R_s=29.7 Ω/□, T=96.2%), strong adhesion (R_s/R₀<125% for 100 tape test), ultra-flexibility (sheet resistance remained almost unchanged after 1 000 bending cycles with a bending radius of 1 mm) and strong corrosion resistance (R_s/R₀<120% after an accelerated aging test under 85℃, 85%RH). We believe this transferring and decorating method for forming AgNWs composite film and the relative techniques for demonstrating flexible touch panel can be popularized to various flexible electronic applications.