By Marge d’Wylde

Chemical Engineer alumus Rebecca Dylla-Spears (Ph.D. ’09, ChemE) is a research scientist at Lawrence Livermore National Lab (LLNL). Rebecca received her Ph.D. with Professor of Chemical and Biomolecular Engineering Susan Muller and Chancellor’s Professor Lydia Sohn in mechanical engineering. 

Rebecca grew up in the small Texas farming town of St. Hedwig, outside of San Antonio where about 1,000 people lived when she was young. After high school, she went on to the University of Texas at Austin (UT) for joint undergraduate degrees in chemical engineering and liberal arts. 

After UT, Rebecca came to California and worked for two years at Clorox in their R&D group. From there, she continued to LLNL working on potassium dihydrogen phosphate (KDP) crystal growth in the National Ignition Facility and Photon Science (NIF&PS) program. 

“After I worked in the lab at LLNL for a while and saw the research opportunities, I decided I wanted to ‘expand my toolbox’ and went to UC Berkeley to get my Ph.D. in chemical engineering,” Rebecca said. “I worked with Susan Muller and Lydia Sohn. My dissertation focused on the use of microfluidic stagnation point flows to trap and stretch DNA for detection of tagged sequences.”

After graduation, Rebecca returned to LLNL. “I worked in the NIF&PS cryogenic deuterium-tritium (DT) layering program. Our experiments resulted in the process used to grow the DT crystal fuel layers required for inertial confinement fusion targets. Everyone at the lab was thrilled when fusion ignition was successfully achieved on December 5th, 2022, in a world first.” 

She continues, “Many generations of scientists contributed to this amazing success. Advances in lasers, optics, and targets were an important part of that. The work is far from done. Finding a solution to creating clean fusion energy in the future is of increasing urgency to the world. Getting to the next step in this grand scientific endeavor—toward sustainable fusion power plants—will require dedication, grit, hard work, and sustained investment.”

Rebecca continues, “I worked on the DT layering project for five years. At the same time, I was also supporting optics research, which gave me experience in colloidal science, optical finishing, and fabrication. This encouraged me to move on to create a research program in additive manufacturing and optics. I became the principal investigator for a large, strategic R&D program to look at three different methods of making optics using additive manufacturing: one area was lightweight mirrors, one was gradient refractive index optics, and the third was graded composition gain media. It has been exciting work because research into glass additive manufacturing is relatively new in the last seven years, compared to other materials like polymers, metals and ceramics.”

Specifically, the team developed optical components with functionally graded material properties that resulted from changes to the optics’ composition, not its shape. The optics are being produced using 3D printing technology with direct ink writing (DIW). After testing many processes, the team chose this approach because it gave them the most control over composition in three dimensions. 

Rebecca enthuses, “We were honored in 2022 when our multi-disciplinary team of physicists, material scientists, chemists, chemical engineers, mechanical engineers, and optical engineers won an R&D 100 award (from R&D World Magazine) for development of the additive manufacturing process which we decided to call ‘Tailored Glass Using Direct Ink Writing Technology’. This technology can be used to print silica-based optics and glass components with customizable forms and spatially varying material properties. The technology will enable fabrication of new kinds of optics.”  

Last year, Rebecca decided to pursue research in another unit at the Lab. “I like to go where my skills can best be used because I enjoy learning new things. I think it’s important to not tell yourself ‘No.’ I’m now working with teams investigating a broader range of materials and manufacturing methods related to national security applications.”

Rebecca continues, “Thinking back on it, my Ph.D. in chemical engineering taught me how to learn anything. With the skills I gained, I can dive into new subjects and become competent. And that has helped me because in my career here at the lab, I go where the need is. I’m the kind of person who likes to keep challenging myself in that way. I know, because I’ve done this multiple times now, that you can become knowledgeable in new subject areas without having the background to start with. Really, that is what my Ph.D. did for me. Having that confidence that a Ph.D. brings, earning it through hard work and diving into something brand new in the graduate lab, is really the thing that lets you know in your future that you’re going to be okay.”