(659c) Design and Fabrication of Functional Surfaces with Modulated Interfacial Properties

My research interests lie in the areas of Surface and Interface Science, Coating Technologies, and Advanced Manufacturing with particular emphasis on developing surfaces with modulated interfacial properties. My past research investigates the manipulation of interfacial properties such as liquid wettability and catalytic capability to develop surfaces with applications in protective coatings, liquid-liquid separation platforms, and environmental remediation. In the future, I plan to expand my research by establishing a fundamental understanding and developing theoretical frameworks of the interfacial interactions taking place at the liquids-solids and gas-solids interfaces. My research agenda will also concentrate on developing manufacturing methodologies with a focus on additive manufacturing technologies to enable rapid and large-scale production of surfaces with modulated interfacial properties.

My PhD research past 5 years under the supervision of Dr. Gibum Kwon at the University of Kansas has been focused on the design and fabrication of functional surfaces by modulating the interfacial properties, particularly at the solid-liquid interfaces. We have demonstrated that modulating the liquid wettability of a solid surface is critical for developing surfaces that can provide protection against hostile environments. In a patent contribution (WO2020037177A1) and a journal publication (ACS App. Mat. & Inter., 11, 33, 2019), we demonstrated super-repellent surfaces that can repel virtually any liquids with varied surface tension and pH values. We also addressed the robustness issue in these surfaces by incorporating the self-healing functionality.

Modulating the liquid wettability have recently found practical applications in the design and fabrication of surfaces with selective wettability towards a particular liquid. My contribution to this area has expanded across diverse separation methodologies that include membrane-based and absorption-based liquids separation. In two journal contributions (Global Challenges, 4, 10, 2020 & ACS App. Mat. & Inter., 12, 43, 2020), we demonstrated separation of oil-water mixtures by utilizing robust inorganic membranes. We also addressed the challenge of membrane fouling by introducing visible light-driven photocatalytic capability to enable self-cleaning of the membrane. Consequently, this research paves the path forward to commercializing and upscaling membrane-based technologies.

Further, the liquids separation by selective absorption of one liquid is a relatively new methodology that can address the traditional limitation of the membrane-based technologies in separating miscible liquid mixtures (e.g., alcohol-alkane). While distillation has been the cornerstone methodology to separate miscible liquid mixtures, its high energy consumption and significant carbon emissions will prevent their extensive applicability in the future. In a patented contribution (US20200399430A1), we utilized a thermo-responsive polymer and demonstrated selective absorption of an alcohol from its miscible mixture with an alkane. The impact of the work became more significant as the polymer and the absorbed liquid are readily recoverable upon mild heating. The experimental findings are compiled and a manuscript is under preparation.

Finally, in the most recent research which is under review in ACS Applied Polymer Materials, we leveraged the thermo-responsiveness of a polymer adsorbent to demonstrate adsorption and on-demand desorption of perfluoroalkyl substances (PFAS) with varied fluoroalkyl chain lengths in water upon switching the temperature. The motivation behind this work was the lack of a viable platform that enables adsorption of PFAS with both long and short fluoroalkyl chain lengths, while enabling on-demand desorption for restoration of adsorbent, as well as the recovery and repurposing of PFAS for more sustainable applications.

My career goal in the future is to leverage my expertise and involve multidisciplinary collaboration to expand my research. In particular, I plan to focus on the following programs:

• Establishing a fundamental understanding and developing theoretical frameworks of the interfacial interactions taking place at the interfaces of liquids-solids and gas-solids. The machine learning tools will be extensively utilized in developing the design frameworks, and performing the optimizations during the parameter studies. The outcomes of this program are expected to address key challenges in the areas including: functional coatings, liquids separation, controlled-release systems, microfluidics, microelectronics, and irrigation systems.
• Extensive application of the surfaces with modulated interfacial properties require them to be amenable to facile manufacturing. However, complicated manufacturing routes have limited a great portion of the contributions only to the bench-scale and pilot-scale proof of concept trials. The aim of this program will be to develop manufacturing methodologies with a focus on additive manufacturing technologies that can enable rapid production of surfaces with modulated interfacial properties at large scales.

Lastly, given the scope of my work that expands across multidisciplinary areas, I believe that my future research can find opportunities to work with diverse federal agencies (NSF, USDA, NASA, DOD, DOE), foundations (ACS Petroleum Research Fund, ACS Green and Sustainable Chemistry), and private sectors (Koch Membranes, Invista Inc.).

Teaching Interests

I have a firm belief that an inspiring teacher should encourage students to look at the big picture of a subject. I also believe that clear and enthusiastic teaching of the course materials will not be sufficient per se to provide a quality instruction. Rather, it is more critical to highlight how the principles can be utilized in real-life applications. My teaching and mentorship experiences have shown me that a classroom can be diverse in race, gender, socio-economic, and learning aptitudes. Hence, I intend to take advantage of diverse resources including: classroom demos, case studies, and inviting guest lecturers from industry and academia. In my experience, the students’ understanding of the course materials can be significantly enhanced by providing them a short presentation on recent publications to show them how the concepts learned in the classroom are applied in real practice. I envision to extent my teaching into my research program by providing hands-on research opportunities for the undergraduate students to work in my group.

My teaching philosophy has evolved through my mentorship experiences and interactions with excellent instructors, particularly my PhD advisor, Dr. Gibum Kwon, at the University of Kansas. As a graduate teaching assistant, I taught class lectures, organized problem solving sessions, and set exam/homework questions for the undergraduate course (ME 208): “Digital Computational Methods in Mechanical Engineering”. In another undergraduate course (ME 360): “Mechanical Engineering Problems", I had the opportunity to supervise the undergraduate students in the general field of surface and materials science. I also received an opportunity to serve as a guest lecturer for a graduate course (ME 790): “Introduction to Surface and Interface Science”. Further, I have the experience of mentoring several undergraduate students in laboratory research. The research results were published in a journal article (Global Challenges, 4, 10, 2020) co-authored by undergraduate students, and another manuscript is currently under preparation. Through these experiences, I have learned that giving students ownership of a project is crucial towards successful accomplishment of a goal. The responsibility and motivation often allow the students to acquire skillset that enable them to become independent educators or researchers in a shorter period.

As I enter the academic ranks, I will continue revising and developing my teaching philosophy. Through my education, I have built a firm foundation in advanced manufacturing methods, principles of thermodynamics, and materials science. My research has enriched my education with fundamentals in surface science and coating technologies, nanotechnology, micro and nanofabrication. I believe these experiences have prepared me to teach core courses.

Lastly, I am also interested in developing a new course related to my field. This course will highlight the fundamentals of surface science, the methodologies utilized to design, fabricate, and characterize functional surfaces and coatings, their applications, and the recent advancements in the field. In this course, students will be expected to develop a perspective on the interdisciplinary issues involved in functional surfaces and critical thinking to develop research ideas.