Thermal Enhancement of Polymer Films with Randomly Oriented Carbon Nanotubes
Class
Article
Department
Mechanical and Aerospace Engineering
Faculty Mentor
Nick Roberts
Presentation Type
Poster Presentation
Abstract
Thin films are a major field in the electrical and packaging industries today. They are used in applications ranging from protective sheathing to microelectronic heat sinks. One of the most under researched fields of thin films is composite thermal interfacing. Previous composite thin film research focuses on embedding vertically aligned materials into a polymer matrix to improve thermal conductivity. In this research, we focus on adding a randomly oriented aggregate, multi-walled carbon nanotubes (CNT), to polydimethylsiloxane (PDMS). Randomly oriented CNTs are easier and more cost effective to manufacture than vertically aligned CNTs but should improve thermal conductivity as much as vertically aligned CNTS. Randomly oriented CNTs create comparable bridges that are as effective as the direct pathways of vertically aligned CNTs. The thin films were tested in a stepped bar apparatus that provides a constant temperature gradient across the film and stepped bars. We then easily extracted the thermal resistance and conductivity from the collected temperature data. Variables such as film thickness and CNT: PDMS weight ratio were individually varied to optimize thermal transport through the films. Ranges of CNT density and film thickness ranged between 0.7 to 3% and 5 to 50 µm, respectively. We found that even though randomly oriented CNTs do not provide a direct pathway for thermal energy transfer, the thermal conductivity of these films are comparable to the vertically aligned films in the full range of film thicknesses. Future research will focus on using other polymer matrices, using single-walled CNTs, and combining randomly oriented and vertically aligned CNTs.
Start Date
4-9-2015 12:00 PM
Thermal Enhancement of Polymer Films with Randomly Oriented Carbon Nanotubes
Thin films are a major field in the electrical and packaging industries today. They are used in applications ranging from protective sheathing to microelectronic heat sinks. One of the most under researched fields of thin films is composite thermal interfacing. Previous composite thin film research focuses on embedding vertically aligned materials into a polymer matrix to improve thermal conductivity. In this research, we focus on adding a randomly oriented aggregate, multi-walled carbon nanotubes (CNT), to polydimethylsiloxane (PDMS). Randomly oriented CNTs are easier and more cost effective to manufacture than vertically aligned CNTs but should improve thermal conductivity as much as vertically aligned CNTS. Randomly oriented CNTs create comparable bridges that are as effective as the direct pathways of vertically aligned CNTs. The thin films were tested in a stepped bar apparatus that provides a constant temperature gradient across the film and stepped bars. We then easily extracted the thermal resistance and conductivity from the collected temperature data. Variables such as film thickness and CNT: PDMS weight ratio were individually varied to optimize thermal transport through the films. Ranges of CNT density and film thickness ranged between 0.7 to 3% and 5 to 50 µm, respectively. We found that even though randomly oriented CNTs do not provide a direct pathway for thermal energy transfer, the thermal conductivity of these films are comparable to the vertically aligned films in the full range of film thicknesses. Future research will focus on using other polymer matrices, using single-walled CNTs, and combining randomly oriented and vertically aligned CNTs.