Owing to their unique mechanical and thermal properties, vertically aligned carbon nanotube (VACNT) films are promising for use as advanced thermal interface materials (TIMs). While there has been much research on the thermal properties of aligned carbon nanotube films, the mechanical modulus along the in-plane direction has received very little attention.
This dissertation describes the design, fabrication, and testing of Carbon Nanotubes (CNTs) using resonators to characterize mechanical properties of them. Carbon nanotubes were prepared using different recipes, resulting in varied thicknesses of Single Wall Carbon Nanotubes (SWNTs) and Multi Wall Carbon Nanotubes (MWNTs). The resonant frequency shifts due to the presence of the CNT films were measured using a Laser Doppler Vibrometer (LDV) system. The extracted moduli of 3.23-26.64 µm-thick SWNT films varied from 10.81 to 371.67 MPa, and those of 0.52-250.0 µm-thick MWNT films ranged from 0.46 to 277.74 MPa. To show the connection between the physics between the Young's the modulus and thickness, an analysis for the height dependence of modulus is provided. After presenting an image analysis, a physical model based on tube properties and film morphology is introduced to predict mechanical properties. The results indicate that CNT films offer a mechanical compliance that is suitable for TIM applications.
No comments:
Post a Comment