Last summer, I had the opportunity to do research in the MIT Mechanosynthesis group, led by Assc. Prof John Hart, under the mentorship of Alvin Tan. This eye-opening endeavor was only made possible with the support of Assc. Prof John Hart, Assc. Prof Joel Yang, Alvin Tan, Haden Quinlan(MIT), Wei Ling (SUTD), my friends and family.
Our research was about realizing the 3D-printing of crystals as a manufacturing technique. This would combine the freedom of geometry in 3D-printing with the diverse material properties of crystals. To create these crystals, we start with an aqueous suspension of particles of roughly a few hundreds of nanometers in diameter. Evaporating the water in the suspension causes these particles to slowly bunch together. When all the water has evaporated, the particles would have bonded together as a solid crystal. We then dispensed the suspension through a needle onto a heated platform with 3-axis movement to create the crystal freeform. Check out the paper here: Direct‐Write Freeform Colloidal Assembly. And interesting link from MIT news: MIT researchers 3-D print colloidal crystals.
To be more specific about my involvement, I did multiple experiments varying parameters such as the concentration of the particles and the movement speed of the heated platform. I made over a hundred samples, with each crystal taking about 30-45 minutes to grow. It gave me a greater appreciation for the pioneers of contemporary 3D-printing technology that is so ubiquitous today. These are really the early days of advanced manufacturing and advanced materials. Freeform crystals have potential applications in new photonic devices such as highly efficient photocatalysts. Also, like natural opals, these crystals exhibit color due to their microstructure. This “structural color” can be used to replace conventional color dyes that can be toxic or fade over time. I hope we’ll see this research translate to a better world.