UC San Diego

As electronics become more powerful and have higher energy densities, it is becoming more and more necessary to find solutions to dissipate these high heat fluxes. One solution to this problem is nanopore evaporative cooling. Based on current literature, the experimental data is far below what is expected from the theoretical calculations.

In this thesis, the experimental results produced heat fluxes much closer to the theoretical values. Experimentally, a maximum heat dissipation of 103 W was achieved on a area which corresponds to a heat flux of on the overall AAO surface or a heat flux of on the active evaporating pore area which is close to the theoretical heat flux of that can be obtained given the membrane parameters. While the results are promising, it still needs to be further studied to obtain higher heat fluxes closer to the theoretical one. In order to do so, membrane parameters of the working porous membrane need to be able to be adjusted.

For the nanopore evaporative experiments done so far, commercially purchased AAO was used. However, commercially purchased AAO is only sold in certain set parameters and the AAO produced has a disordered structure, both of which are not useful for future experimental purposes. Therefore, AAO needs to be fabricated in the lab to meet experimental needs.

The fabrication of AAO on high purity aluminum (99.997%) with 0.3 M Oxalic Acid at 40 V at was achieved. With the given fabrication parameters an average pore size of ~80 nm was achieved with a circularity of 0.91 while the commercially purchased AAO had an average pore size of ~200 nm with a circularity of 0.80.

The initial nanopore evaporative cooling experiments will be discussed along with the process of fabricating usable AAO for these experiments.