Graphitized-rGO/Polyimide Aerogel as the Compressible Thermal Interface Material with Both High in-Plane and through-Plane Thermal Conductivities

Abstract

Reduced graphene oxide (rGO) aerogels with a three-dimensional (3D) interconnected network provides continuous heat transport paths in multi-directions. However, the high porosity of rGO aerogels commonly leads to very low thermal conductivity (TC), and defects and grain boundaries of rGO sheets result in a high extent of phonon scattering, which is far from satisfying the requirement of thermal interface materials (TIMs). Here, a compressible graphitized-rGO/polyimide (g-rGO/PI) aerogel was prepared by the ice-template method and “molecular welding” strategy. The regular cellular structure and closely packed cell walls bring the g-rGO/PI aerogel high compressibility, which made the aerogel can maintain the continuous thermal transport paths well even in highly compacted status. The rGO sheets in the cell wall surface are welded up by g-PI during imidization and graphitization treatment, providing efficient channels for phonon transportation in the 3D network. The g-rGO/PI aerogel in a compressive strain of 95% has a high TC in the plane of 172.5 W m−1k−1 and a high TC through the plane of 58.1 W m−1k−1, which is superior to other carbon-based TIMs previously reported.

Grafting amino groups onto polyimide films in flexible copper clad laminates using helicon plasma

“…The characteristic peak intensity of the −NH2 group is the highest at the −Vs of 100 V. The above results indicate that the amino groups were successfully grafted onto the surface of the plasma-treated PI films and that the degree of amino group grafting was optimized at a −Vs of 100 V. To investigate whether the amino groups were successfully grafted onto the PI film surface, the chemical bonds of the PI films following amino group grafting were analyzed by measuring the XPS profiles of the plasma-treated PI film. As shown in Figure 4a-f, the peaks at approximately 288.6, 286.3, 285.6, and 284.7 eV are the characteristic peaks of the C=O [28], C−O [29,30], C−N [31], and C−C bonds [32], respectively. The intensity of the characteristic peak of the C−N bond is the highest at the −V s of 100 V. As shown in Figure 4g-l, the peaks at approximately 532.2 and 531.3 eV are the characteristic peaks of the C−O and C=O bonds [33], respectively.…”

Grafting Amino Groups onto Polyimide Films in Flexible Copper-Clad Laminates Using Helicon Plasma

“…To investigate whether the amino groups were successfully grafted onto the PI film surface, the chemical bonds of the PI films following amino group grafting were analyzed by measuring the XPS profiles of the plasma-treated PI film. As shown in Figure 4 a–f, the peaks at approximately 288.6, 286.3, 285.6, and 284.7 eV are the characteristic peaks of the C=O [ 28 ], C−O [ 29 , 30 ], C−N [ 31 ], and C−C bonds [ 32 ], respectively. The intensity of the characteristic peak of the C−N bond is the highest at the −V s of 100 V. As shown in Figure 4 g–l, the peaks at approximately 532.2 and 531.3 eV are the characteristic peaks of the C−O and C=O bonds [ 33 ], respectively.…”

Skin-inspired, sensory robots for electronic implants

“…The detailed chemical composition analysis of the nanocomposite appears in Figs. S13-S15 and Supplementary Note S2 [45][46][47][48][49]. These functionalities would be of great value for soft robots that seek to achieve multifunctionality and local sensing capabilities approaching skin.…”