Self-suspended polyimide (PI) composite films were fabricated. Their diameter and thickness were 2.5 in. and 260 nm, respectively. A high ratio of diameter to thickness of 2.4 × 105 was obtained. The multiwalled carbon nanotubes (MWCNTs) were filled into PI to improve the optical absorption and the photothermal response. By using the N-methyl pyrrolidone solvent for both MWCNTs and poly(amic acid), a homogeneous dispersion of MWCNTs with up to 15% content was obtained. Under the thermal treatment of 300 °C, the composite films were successfully synthesized, which was proved by the measurements of Fourier transform infrared spectrum and x-ray diffraction. Compared with the pure PI film, the optical absorption of the composite films at 532 nm wavelength increased from 10% to 28%. The steady and transient photothermal properties of the composite films were investigated. In the steady state, a temperature rise of 145 °C was obtained under 0.7 W/cm2 illuminating laser power density. The temperature increased by 29 times compared with that of the pure PI film. The corresponding photothermal conversion efficiency improved to 70.8%. In the transient state, the photothermal response time was 7.5 ms, which was only half that of the pure PI film. The excellent photothermal properties of these self-suspended MWCNT/PI composite films highlight their potential applications in micro- and nanoscale devices for photo detection and thermal imaging.

中文翻译：

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具有改进光热性能的自悬浮碳纳米管/聚酰亚胺复合膜

制备自悬浮聚酰亚胺 (PI) 复合膜。它们的直径和厚度分别为 2.5 英寸和 260 纳米。获得了 2.4 × 105 的高直径与厚度比。将多壁碳纳米管（MWCNT）填充到 PI 中以提高光吸收和光热响应。通过对多壁碳纳米管和聚酰胺酸使用 N-甲基吡咯烷酮溶剂，获得了含量高达 15% 的多壁碳纳米管的均匀分散体。在300°C的热处理条件下，复合薄膜成功合成，傅里叶变换红外光谱和X射线衍射测量证明了这一点。与纯 PI 薄膜相比，复合薄膜在 532 nm 波长处的光吸收从 10% 增加到 28%。研究了复合薄膜的稳态和瞬态光热性能。在稳态下，在 0.7 W/cm2 照射激光功率密度下获得 145 °C 的温升。与纯PI薄膜相比，温度提高了29倍。相应的光热转换效率提高到70.8%。在瞬态下，光热响应时间为 7.5 ms，仅为纯 PI 薄膜的一半。这些自悬浮 MWCNT/PI 复合薄膜优异的光热性能突出了它们在用于光检测和热成像的微米和纳米级设备中的潜在应用。与纯PI薄膜相比，温度提高了29倍。相应的光热转换效率提高到70.8%。在瞬态下，光热响应时间为 7.5 ms，仅为纯 PI 薄膜的一半。这些自悬浮 MWCNT/PI 复合薄膜的优异光热性能突出了它们在用于光检测和热成像的微米和纳米级设备中的潜在应用。与纯PI薄膜相比，温度提高了29倍。相应的光热转换效率提高到70.8%。在瞬态下，光热响应时间为 7.5 ms，仅为纯 PI 薄膜的一半。这些自悬浮 MWCNT/PI 复合薄膜的优异光热性能突出了它们在用于光检测和热成像的微米和纳米级设备中的潜在应用。