Atar Nurit, Grossman Eitan, Gouzman Irina, Bolker Asaf, Hanein Yael
Space Environment Department, Soreq NRC , Yavne 81800, Israel.
ACS Appl Mater Interfaces. 2014 Nov 26;6(22):20400-7. doi: 10.1021/am505811g. Epub 2014 Nov 13.
Chemical vapor deposition (CVD)-grown entangled carbon nanotube (CNT) sheets are characterized by high electrical conductivity and durability to bending and folding. However, since freestanding CNT sheets are mechanically weak, they cannot be used as stand-alone flexible films. In this work, polyimide (PI) infiltration into entangled cup-stacked CNT (CSCNT) sheets was studied to form electrically conducting, robust, and flexible films for space applications. The infiltration process preserved CNTs' advantageous properties (i.e., conductivity and flexibility), prevented CNT agglomeration, and enabled CNT patterning. In particular, the CNT-PI films exhibited ohmic electrical conductance in both the lateral and vertical directions, with a sheet resistivity as low as 122 Ω/□, similar to that of as-grown CNT sheets, with minimal effect of the insulating matrix. Moreover, this high conductivity was preserved under mechanical and thermal manipulations. These properties make the reported CNT-PI films excellent candidates for applications where flexibility, thermal stability, and electrical conductivity are required. Particularly, the developed CNT-PI films were found to be durable in space environment hazards such as high vacuum, thermal cycling, and ionizing radiation, and hence they are suggested as an alternative for the electrostatic discharge (ESD) protection layer in spacecraft thermal blankets.
化学气相沉积（CVD）生长的缠结碳纳米管（CNT）片材具有高导电性以及对弯曲和折叠的耐久性。然而，由于独立的CNT片材机械性能较弱，它们不能用作独立的柔性薄膜。在这项工作中，研究了将聚酰亚胺（PI）渗透到缠结的杯状堆叠碳纳米管（CSCNT）片中，以形成用于空间应用的导电、坚固且柔性的薄膜。渗透过程保留了碳纳米管的有利特性（即导电性和柔韧性），防止了碳纳米管团聚，并实现了碳纳米管图案化。特别地，CNT-PI薄膜在横向和垂直方向上均表现出欧姆电导，薄层电阻低至122Ω/□，与生长态的CNT片材相似，绝缘基体的影响最小。此外，这种高导电性在机械和热操作下得以保留。这些特性使所报道的CNT-PI薄膜成为需要柔韧性、热稳定性和导电性的应用的极佳候选材料。特别是，已开发的CNT-PI薄膜在高真空、热循环和电离辐射等空间环境危害中表现出耐久性，因此建议将它们用作航天器隔热罩中静电放电（ESD）保护层的替代品。
