|MIT Department: Mechanical Engineering
Faculty Mentor: Prof. Evelyn Wang
Undergraduate Institution: Stanford University
Hi! My name is Cameron and I’m a junior studying Mechanical Engineering at Stanford. I haven’t yet pinned down what I want to do, but anything in the realm of conservation and sustainability really excites me!
Quality Analysis of Slope-Assembled Opals
Cameron Kilpatrick1, Carlos Diaz2 and Evelyn Wang2
1,2 Department of Mechanical Engineering, Massachusetts Institute of Technology
Self-assembly of micro-to-nanoscale particles has recently gained traction as a nanofabrication technique due to the process’s ability to create highly ordered microstructures with no need of manual control of the individual components. Slope assembly in particular merits further exploration as it is a particularly fast method, allowing for rapid fabrication with high-throughput and order. The orderliness of a self-assembled opaline array can be quantified in terms of its quality, which in turn can have a strong influence in the structure performance. Quality values range from 0 to 1, with numbers closer to 1 being more orderly and thus desired. While slope assembly can reliably create good-quality samples on glass, it is not successful on metals, which are substrates critical to many potential applications. To remedy this, in this work, a transfer method is used to first form an opal layer on glass, remove the layer by submersion in water, and pick up by the desired material. Using an image processing algorithm, we found that while glass samples can consistently produce quality values above 0.7, transferred samples featured large cracks and vacancies causing some samples to have quality ratings of as low as 0.4. However, in spaces not affected by these vacancies, copper deposited on glass and mirror-polished copper produced almost identical structures and quality values. Our results indicate that substrate transfer is a valid approach with the potential to allow for the fabrication of slope self-assembled structures on arbitrary substrates. Such structures can have applications in thermo-fluidic devices and electrochemical systems.