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For this year-long design project, a team of four engineering seniors was tasked with building an improved photoreactor system for the Cooley Lab’s photoinitiated polymerization reactions. The existing reactors suffered from inconsistent lighting conditions and an extreme rise in the test space temperature of 20-45°C above the ambient temperature. Additionally, the four different boxes that the lab used took up significant bench space and varied widely from one another. These adverse conditions limited the Cooley Lab’s ability to generate quality, replicable data for publication, so the team sought to provide an alternative. The final photoreactor design improves the end-user functionality by incorporating removable modular light trays of three different wavelengths, a high-speed fan for regulating the internal temperature, convenient drawers to hold samples in cuvettes or 96 well plates, and a button-operated user interface to automate the reaction runtime.

The team built the photoreactor with the goal of meeting the following project requirements: minimize heat generation, produce light that is constant in time and space for three different wavelength options, run simultaneous and independent reactions in cuvette or 96 well plates, withstand the cleaning chemicals used in an organic chemistry lab, and provide an understandable user interface that runs autonomously for a set run time. After extensive testing, our prototype has met or nearly met all of its requirements. The final design reduced the internal heat generation to +2°C for green light panels, +3°C for UV panels, and +6°C for blue panels. This slightly exceeds our goal of +2°C, but is a significant improvement from the previous system because it represents an overall reduction in both temperature and variability between wavelength options. In 96-well orientation, the green and blue light panels produce a spatial temperature distribution where all light intensities are within 5% of the mean value with respect to both time and space. The exterior of the photoreactor is constructed from acetone-resistant high-density polyethylene (HDPE), and the user interface accurately shuts off the lights and fan after the timer reaches a given reaction time.

After completing our design, we partnered with current research students in the Cooley lab to run side-by-side reactions in our prototype and the former photoreactor system. Our prototype increased the degree of polymerization during the reaction and the automatic shutoff was significantly more convenient for the research students. At this time, we have a fully operational prototype to present to our sponsor that satisfies the major requirements that we set for the project.

In this document, we discuss the project requirements in more detail and present a summary of the data from each of our tests. In addition, we give an overview of the construction methods we used and instructions for safe operation of the photoreactor. We would like to thank Dr. Cooley for her responsiveness and support throughout this process as well as our Senior Design Administrator, Dr. Darin George, and our Project Advisor, Dr. Keith Bartels. Please do not hesitate to reach out to the project team if you have any questions or concerns, and we are pleased to present our work in this final project report.


Keith Bartels, Team Adviser