Abstract: Polyelectrolytes (PEs) have ubiquitous applications in both commodity materials in our everyday life and advanced functional materials to solve emergent challenges. Many biomacromolecules, like proteins, DNA, and RNA, are essentially PEs. Modeling ion correlations in inhomogeneous polymers and soft matters with spatially varying ionic strength or dielectric permittivity remains a great challenge. We develop a new theory which systematically incorporates electrostatic fluctuations into the self-consistent field theory for polymers. Applied to polyelectrolyte brushes, the theory predicts that ion correlations induce non- monotonic change of the brush height: collapse followed by reexpansion. Strong ion correlations can trigger microphase separation, either in the lateral direction as pinned micelles or in the normal direction as oscillatory layers. We also predict that the interactions between two opposing PE brushes show hysteretic feature in the presence of multivalent ions: repulsive in the compression branch and adhesive in the separation branch. Our theoretical predictions are in good agreement with the experimental results reported by Tirrell group. Based on the theory, we develop a computational platform to study a variety of conformation and self-assembly behaviors of biomacromolecules, including protein aggregation, salt effect on the liquid-liquid phase separation of proteins, protein-ATP binding and neurofilament-derived protein brushes.
Bio: Rui Wang earned both his bachelor’s degree (2005) and master’s degree (2008) in Chemical Engineering from Zhejiang University, China. He then moved to the U.S., where he earned his PhD degree in 2014 at Caltech advised by Prof. Zhen-Gang Wang. During 2015-2018, he worked with Prof. Bradley Olsen and Jeremiah Johnson at MIT as a postdoctoral scholar. He started his faculty career at UC Berkeley in 2019. He is also a faculty scientist in the Material Sciences Division in the Lawrence Berkeley National Laboratory. He has won a few awards in academia, including the Doctoral New Investigator Award in ACS Petroleum Research Fund and Cupola Era fellowship at UC Berkeley.
