(2jr) Ion and Polymer Containing Systems: From Nanoscale Physics to Engineering Applications

My research efforts have predominantly focused on developing a molecular scale understanding of hydrated polymeric systems in ionic environments. In this endeavor, I have unraveled key physical insights, established structure-property relationships, and suggested principles for the design of nanosystems with high engineering significance. My doctoral research at the University of Maryland followed a two-pronged approach, wherein I first utilized a combination of theoretical modeling and molecular simulations to investigate the structure and dynamics of surface-grafted hydrophilic polyelectrolyte (PE) brushes, and then built upon this knowledge by probing ion and water transport in PE-brush grafted nanochannels. This work was instrumental in demonstrating the possibility of simultaneous electrokinetic energy generation and flow enhancement in PE brush-grafted nanochannels by leveraging the phenomenon of overscreening in dense PE layers. Currently, I am a postdoctoral fellow at the University of Texas at Austin. My postdoctoral research focuses on investigating polymeric nanofiltration membranes for facilitating ion-ion separations. I have leveraged coarse-grained molecular dynamics (CGMD) simulations to elucidate the impact of host-guest interactions on ionic permselectivity of ligand-functionalized polymer membranes (LFPMs) under both single and mixed salt conditions. I also developed a mathematical framework for capturing the role of ion-ion correlations on salt transport in mixed salt systems, which was utilized in conjunction with molecular dynamics (MD) simulations to probe selective salt transport in LFPMs and ion-exchange membranes. Recently, by leveraging all-atom MD simulations, I unraveled the pivotal role played by the rotational dynamics of water molecules in dictating the anomalously high anionic selectivity of certain zwitterionic amphiphilic copolymer (ZAC) membranes, and then used these results to devise design principles for developing highly selective ZAC membranes. Currently, I am utilizing a reduced order model to investigate ionic transport in zwitterion-functionalized nanopores of varying morphologies. This work will help elucidate selective ionic permeation in zwitterionic polymer membranes.

My future research group will explore three distinct categories of ion and polymer containing systems:

1) Polymerized lyotropic liquid crystal assemblies for applications in chemical separations and catalysis: Polymerized lyotropic liquid crystals (pLLCs) consist of cross-linked amphiphiles dispersed within a polar solvent. pLLCs are envisaged as highly desirable materials for a plethora of applications due to the presence of regular tunable nanoscopic morphological features. My future research group will investigate ionic transport in pLLC assemblies of various chemistries and morphologies with the goal of designing novel membranes that can facilitate highly complex ion-ion separations. Furthermore, my group shall explore the usage of functionalized pLLC assemblies in catalyzing chemical reactions by employing reactive molecular dynamics simulations.

2) Highly conductive polymer-based electrolytes for lithium-ion batteries: The high volatility, flammability and poor mechanical strength of organic liquid electrolytes have raised serious safety concerns regarding the usage of lithium-ion batteries. While polymer-based electrolytes (both solid-state and quasi solid-state) can alleviate these shortcomings, their widespread adoption is hindered by their relatively low ionic conductivity. To this end, my research group will focus on the design and development of novel nanoconfined solid polymer electrolytes that can exhibit high enough ionic conductivity for commercial applications (greater than 10^-3 S.cm^-1 ) whilst circumventing the limitations of conventional liquid electrolytes.

3) PE brush-grafted synthetic nanopores for use in ionic current rectification: Surface charge-bearing synthetic nanopores find extensive use as nanofluidic diodes by allowing for the preferential passage of ionic current in one direction over another. Both theoretical and experimental studies have revealed that replacing the surface charges of nanopores with closely grafted PE molecules (i.e., PE brushes) can help improve their current rectification characteristics by altering the distribution of fixed charges within the pore. However, despite the immense potential of these systems, the impact of PE brush structure and chemistry on the rectification properties of synthetic nanopores is still poorly understood, which hinders the usage of these systems in real-world applications. My research group will employ computer simulations to investigate ionic conduction in PE brush-grafted asymmetric nanopores and subsequently propose principles for the design of functionalized nanopores with excellent rectification characteristics for lab-on-a-chip devices.

My extensive experience with working on ion transport in hydrated polymeric systems puts me at a unique vantage point to navigate around the potential obstacles and challenges that shall arise while pursuing the proposed research. My group will adopt a computational and theoretical modeling-based approach, which will not only help in illuminating the complex nanoscale physics of ion and polymer containing systems, but also enable us to suggest principles for the optimal design and development of these systems for addressing urgent engineering challenges.

Teaching Interests

My teaching philosophy revolves around the dissemination of knowledge in a well-organized, structured, and harmonious manner that allows for the students to connect the dots between seemingly disjointed concepts. The formation of robust associations between the underlying concepts inculcates a strong foundational knowledge base from which the students can draw upon when challenged with complex real-world problems in their careers. I am willing and able to teach any of the courses within the Chemical Engineering curriculum, especially those related to transport phenomena, numerical methods, and thermodynamics.

During my graduate studies at the University of Maryland, I was selected to participate in the A. James Clark School of Engineering’s ‘Future Faculty Program’, where I received semester-long training pertaining to the principles of effective teaching. It was here that I found out about the concept of different learning styles (visual, auditory, reading/writing, kinesthetic), and most importantly the fact that students learn best when information is presented to them in accord with their preferred learning style. Therefore, in order to ensure that all students in my classroom have a fruitful learning experience, my instructional methodology will follow a multimodal approach consisting of a combination of blackboard teaching, PowerPoint presentations, diagrams, animations, audio clips and physical prototypes. Providing multiple avenues of learning the underlying concepts will help foster an environment where students with diverse identities and learning styles are able to achieve their learning goals. One of my core tenets is that students should be equal participants in the process of teaching and learning, rather than mere spectators within the classroom. Thus, I shall adhere to the principles of active learning and ensure that students remain constructively engaged in the classroom activities.

Tackling practical engineering problems requires the ability to apply theoretical concepts to real-world situations. Thus, I will focus on imparting problem-solving skills to the students in addition to teaching them the fundamentals. At the beginning of each new topic, I shall provide examples covering a wide range of engineering disciplines to ensure that students across all disciplines remain motivated and learn the concepts in a way that is directly applicable to their respective academic pursuits. In addition, the practical examples will help students understand the importance of the material being taught. I strongly believe in evaluating students in a continuous and comprehensive manner. Therefore, I shall not assign too much weightage to the end-term examination. Instead, my assessment methodology will involve periodic quizzes and take-home assignments that require reasoning from first principles instead of rote memorization. This will prepare students for challenges beyond the classroom and will be immensely valuable in their long-term career aspirations as an engineer/scientist. To incentivize the students to plug their knowledge gaps, I will provide them with prompt feedback on their assignments and allow them to resubmit their assignments with corrected solutions for extra credit.

I shall make efforts to ensure that all students irrespective of their background, ethnicity, race, gender, sex, etc. feel included and respected in my classroom. Firstly, I will create a discussion group on the course website wherein the students can freely interact with one another in a safe environment. These interactions will enable the students to learn from the diverse perspectives of their colleagues and create a healthy atmosphere of mutual respect. Secondly, I will ensure that students with physical and/or mental disabilities are given additional time for their submissions in accordance with the University policy. Thirdly, I will prescribe textbooks that are freely available from the University library instead of mandating that the students buy expensive textbooks. This will go a long way in ensuring that students from less privileged backgrounds are at an equal footing will the rest of the class. Finally, I will hold interaction hours each week where the students are able to directly ask questions and provide feedback on the course. This will keep me abreast of any potential issues/difficulties faced by the students, whilst also helping me identify the topics that need to be revisited in the classroom.

My prime objective as a teacher shall be to instill enough curiosity in my students that they feel motivated to explore the subject further by themselves, even after the formal completion of the course. This way, the students will become lifelong learners and garner the confidence to tackle the most challenging problems in their respective fields. Through my teaching, I aspire to raise passionate and inspired students who will become the next generation of world-class engineers, scientists, and innovators.