高分子物理与化学实验室将于下周二（24号）上午10:00在3#101会议室召开高分子科学前沿讲座2019年第17期，本次由赵江老师组邀请Dr. Guang Chen（Princeton University）作报告，具体内容请您参见附件。欢迎各位老师到场参加！

Abstract: Polyelectrolytes (PE) solutions are charged polymers in polar solvents, which have been extensively studied attributing to their ubiquitous nature and their use in a large number of applications such as energy storage, drug delivery, oil recovery, bio-medical devices and food industry. Due to the electrostatic interactions among the charged monomers and surrounding electrolyte ions, the microstructure and the macroscopic dynamics of the PE chains are responsive to environmental modulations (e.g., added salt and pH). To understand the electrostatics and its contribution to the dynamics of semi-dilute PE solutions, we introduce cell models with simplified geometries, solve the Poisson-Boltzmann equation within and beyond the Debye-Hückel limit, and analysis the explicit ion distributions for scenarios with non-overlapping and overlapping electric double layers. We identify consecutive regimes dependent on the magnitude of the ratio of the polymer concentration to the salt concentration, which rationalize the unexplained observations and classical PE solution theories and shed light on the effects of polymer concentration, salt contamination, added salt and charge strength on the properties of semi-dilute unentangled PE solutions. Meanwhile, this new theoretical model can be applied to many other colloidal systems such as polyelectrolyte brushes, clay particle suspensions and bacterial colonies.

About the speaker: Dr. Guang Chen is now postdoctoral research associate in the Complex Fluid Lab at Princeton University, working with Prof. Howard Stone. She got her Ph.D. degree from University of Maryland in USA in 2016 after getting her master degree from Columbia University and her bachelor degree from Shanghai Jiaotong University. Her research interests are related to fluid mechanics and soft matter physics, including Electrostatics in charged complex fluids, polyelectrolytes in solutions and at interfaces, electrokinetics, fluid-structure interaction, contact line dynamics, 3D printing / aerosol jet printing, advection-diffusion reaction.