Yimin Luo: Harnessing out-of-equilibrium phenomena for functional materials

The School of Engineering & Applied Science is proud to welcome its newest faculty members for the 2022-23 academic year. The large influx of faculty members – 13 so far, with more to be announced soon – marks the rapid growth of the School and investment in the research areas illustrated in the SEAS Strategic Vision.

The latest faculty arrivals are valuable additions to the chemical and environmental, computer science, and electrical engineering departments. Their expertise includes sustainability, artificial intelligence, robotics, quantum computing, cybersecurity, and optoelectronic materials.

Upon their arrival, we asked these new faculty members questions about their work, their motivations, potential collaborations, and much more:

Yimin Luo, Mechanical Engineering & Materials Science


Shanghai, China.

Prior academic history:

I attended high school in Waller, TX, a small town of ten thousand people between Houston and Austin, where I learned about the Rodeo and competed in the University Interscholastic League. I spent my undergraduate years at Rice University, a small urban campus in Houston with a residential college system, just like Yale. There I was first exposed to research, first as an undergraduate assistant in a fly lab, later joining a lab focusing on fabricating carbon nanotube composites. Fascinated by complex fluid interfaces and the material applications they enable, I continued to the University of Pennsylvania to attend graduate school, followed by postdoctoral training at the University of Delaware and the University of California Santa Barbara.

How would you summarize your research?

My research interests compose of two thrusts spanning the areas of colloids, complex fluids, and biomaterials. First, I design high-throughput experiments to obtain microscopy, rheology, and scattering measurements, for estimating quantitative information from dynamic processes, such as system under shear flow, phase separation, or migration. Second, I develop statistical and machine learning approaches to automate experimental processes and optimize experimental designs. I work primarily in three types of systems: shear-induced deformation and rearrangements of soft particles, collective behaviors of active colloids, and cell-substrate interactions, with goals to develop new methods for material processing, and assemble biological and nonbiological building blocks into high-dimensional hierarchical structures. Tools and rules established in one system can usually inform the other. Whenever possible, I design high-throughput experiments to augment our capacity and bring in statistical and physical models to optimize experimental designs and accelerate scientific discovery.

What inspired you to choose this field of study?

Microscopy fully embodies the saying "to see a world in a grain of sand". I have always had an engineer's fascination with microscale phenomena. These dynamics not only track system behaviors but also unveil information about the energy landscape surrounding these building blocks. While a variety of tools are available to characterize static systems, recent years have witnessed a burgeoning interest to monitor dynamic, adaptable, and out-of-equilibrium systems through microscopy. Microscopy images and scattering experiments have historically been used for direct visualization and qualitative information, but more recently the view is shifting toward quantitative analysis. Modern microscopes, equipped with the latest automation capabilities, for instance, can measure samples from mesoscale down to nanometer length scale, collecting data from several different channels in parallel, vertical z-stacks, time-lapse sequences, etc, and generate TB of data in a single experimental setting. These reams of data can be exploited using statistical learning to generate useful relationships to guide soft matter structure. My work is further inspired by recent momentum in the biophysical understanding of emergent phenomena in the context of physical interactions. The development is spurred by advances in synthetic biology, additive manufacturing, and artificial intelligence, making supramolecular structures routinely available and providing the analytical infrastructure to interpret the resulting data streams.

Where do you see the field 10 years from now?

Cell-substrate interactions are a fundamentally important biological phenomenon. It is also critical to medicine and material science applications such as tissue scaffolding and wound healing. This process is highly reciprocal: extracellular matrix (ECM) composition affects motility, proliferation, differentiation, and the protein production of cells, in return, cells also remodel the ECM. However, most engineered substrates have static properties. Two trends are inevitable: the first is the routine adaptation of 3D, realistic, dynamic ECM models that respond to cell activities for drug screening and bioassays; another is the further convergence of condensed matter physics and biology, which has proven to be exceptionally fruitful so far. The complexity of biological systems precludes a global description at this stage; nevertheless, we continuously discover simple physical rules that govern the intricate behavior of biological systems, which in turn enable us to harness them for functional (bio)material design.

What brought you to Yale?

Above all, Yale advocates for a vision towards an integrated approach to tackling scientific problems beyond traditional, disciplinary boundaries - a new paradigm I deeply believe in. I view teaching and research to be reciprocal and inseparable pairs, where Yale emerges as a leader in both undergraduate education and world-class research. My natural intellectual home lies within the Physical and Engineering Biology (PEB) Program at Yale, which is made up of the most passionate and intelligent group of people I have ever met, who are exploring topics close to my heart. Having gone to a small college myself, I am a proponent for a liberal arts education. During my first visit to the Yale campus, I was in awe of its extraordinary breadth and depth in humanities, arts, and architecture. These heritages provide context to our longings, perceptions, and emotions, and are what ultimately make us human.

What areas outside of the Department of Mechanical Engineering and Materials Science do you seek to create impactful research collaborations or partnerships?

My research aims at bridging the gap between experiments and modeling by designing experimental protocols to enable screening of a comprehensive range of conditions, allowing us to explore fundamental scientific questions about self-assembly and spatial organization. This work is also complementary to the research taking place in the Department of Physics, in experimental condensed matter, in the Department of Chemical and Environmental Engineering, and soft matter and complex fluids. During my career, I also benefit extensively from interactions with statisticians and roboticists to refine experimental workflow, interpret results, refine modeling, and improve control over the assembly.

Are there any courses that you look forward to teaching/creating?

I will be teaching thermodynamics in the spring, which is concerned with heat, work, and energy transfer. It is an elegant subject for which there are simple and systematic rules governing each interaction: minimization of energy and maximization of entropy. But the consequences are profound: it governs the phase transition from water to ice, our ability to convert heat to work led to the first industrial revolution, while the same rules are implicated in the evolution of the universe. Central to this subject is the idea of an equilibrium, where the number of bits in a particular state is conserved, and we arrive at the equality of temperature, pressure, chemical potential, etc.

I hope to develop an advanced course to explore scenarios when the rule must be modified due to activities. Active matter describes systems consisting of agents, each individually extracting energy from their environment, and warranting an out-of-equilibrium description. Living organisms ranging from a herd to an individual to a cell all exploit these strategies in some ways to collectively form bottom-up constructions of varying degrees of order. On the other hand, engineered entities manifest collective behaviors bearing striking resemblance to living systems. By exploiting their self-directed capacities, building blocks can be patterned in a well-behaved manner to form functional structures.

What are your interests outside of the lab?

I enjoy walking around my neighborhood on a weekend morning, getting the freshest baked goods, checking out the farmer's market, and relishing an occasional brunch. I also get my mood-boosting endorphins from group fitness classes ranging from vinyasa yoga to Zumba to boot camps.

What is the best New Haven Pizza?

I like a good slice of a super thin, brick-oven pizza wherever I can find it.

Back to the 2022-2023 New SEAS Faculty Profiles