(2ih) Harnessing Water Entropy and Electric Field to Design Aqueous Polymer Systems for Sustainability and Bioengineering

My research group will integrate multiscale simulation, theory, and machine learning, to advance the fundamental understanding and design of aqueous polymer complex systems, for application in underwater adhesion, anti-fouling, soft robotics, and biomedicine.

Aqueous polymer complex systems, including polyelectrolyte coacervates, hydrogels, and protein complexes, have emerged as promising materials with significant potential for addressing the challenges in sustainability and bioengineering, from environment-friendly materials to pharmaceuticals. These systems are often formed by liquid–liquid phase separation (LLPS) involving charged polymers in water. Harnessing the full potential of these systems requires fundamental understanding and control of their structure, thermodynamics, and dynamics in bulk and at interfaces. A central challenge in this area is understanding effects occurring over a broad range of length and time scales, from nanoscale water structure, ion solvation, to mesoscale polymer association, to macroscopic response under external fields. While existing simulation/theory studies mostly focus on the role of polymers, their predictions on material behavior have major discrepancies with experiments. My recent studies have revealed two crucial effects in these systems: 1) Most charged systems are driven by entropy gained from water reorganization during polymer associations; 2) The structure and dynamics of these systems are very sensitive to electric field.

My efforts have directly inspired two new research directions: 1) Harnessing water entropy for polymer self-assembly, a new area that has boundless potentials for designing novel water-based polymer materials. 2) Using external electric field to control polyelectrolyte complexes, which offers a new sustainable approach to tune the systems’ behavior in addition to conventional methods by salt and temperature. The mission of my research group is to exploit these two exciting avenues in designing novel aqueous polymer systems for sustainability and bioengineering applications.

Towards this end, my research program will initially focus on the following aims:

Aim 1: Elucidating the electrochemical and mechanical properties of polyelectrolyte complex coacervates at underwater interfaces, with emphasis on designing underwater adhesives, anti-fouling surfaces, and membrane-mediated coacervate droplets assembly.

Detailed research projects:

1.1 Liquid coacervates for underwater surface adhesion.

1.2 Polyzwitterion–polyelectrolyte complexes for underwater antifouling coating.

1.3 External electric field guided coacervate–membrane interaction.

Aim 2: Developing predictive understanding of the multi-scale mechanisms that govern ion, water, and polymer behavior in electric-field responsive polymer complex systems for soft robotics.

Detailed research projects:

2.1 Electric field drive hydrogel–coacervate transition for robotic actuation.

2.2 Electric field guided motion and assembly of underwater complex coacervates.

Aim 3: Elucidating the effects of water reorganization on the structure and thermodynamics in biopolymer association using simulation and machine learning, with focus on biomolecular design for pharmaceuticals.

Detailed research projects:

3.1 Uncovering water reorganization entropy effects on protein morphology and protein–ligand binding affinity. This insight will be significant for protein engineering and drug design.

3.2 Unitizing water reorganization to design biomolecular complex with enhanced thermal stability.

These aims are unified by two themes: (i) To elucidate the novel structure, thermodynamics, and dynamics in water-based polymer complex systems due to the interplay between electrostatics, hydrodynamics, water reorganization, and external fields; (ii) To leverage the fundamental insight obtained in (i) for the design of sustainable technologies and bioengineering in aqueous environment.

I have developed powerful coarse-grained simulation method that integrates electrostatics, hydrodynamics, and external field to study LLPS dynamics and structure at mesoscale level, and have discovered many novel effects of water reorganization and electrostatics. In my PhD research, I developed multi-scale MD simulation methods and machine learning models to understand the effects of interactions between water, polymer and nanoparticles on the structure, thermodynamics and dynamics of aqueous polymer gels and nanocomposites. My experience in developing simulation and machine learning models for polymer systems, and my training in thermodynamics, polymer physics, and electrostatics allow me to develop efficient, predictive computational and theoretical models to carry out the proposed projects.

Teaching Interests:

A passion for teaching is one of the most important factors driving me to pursue a career in academia. As a researcher, I enjoy the joy of understanding the fundamentals in chemical engineering and use my knowledge for addressing sustainability and bioengineering issues for societal benefits. My goal for teaching is to pass my knowledge in this field and passion to the next generation and to help them understand and enjoy the knowledge, think critically and creatively, explore new solutions, and create a better future for the world.

Based on my teaching experience and my knowledge, I feel qualified to teach both introductory and up-level courses in chemical engineering and related areas. For example, I would enjoy teaching core chemical engineering courses such as thermodynamics, statistical mechanics, and transport phenomena. I would be also thrilled to share my knowledge though special topics courses such as machine learning, molecular dynamics simulation, and polymer physics.