Recently, Jiaxing Yuan, alumni (class of 2016) of Zhiyuan College and now a postdoctoral researcher at the University of Tokyo, published a paper titled "Charge Regulation Effects in in Polyelectrolyte Adsorption on Physical Review Letters, a top Physics journal, as the first author and co-corresponding author.

Polyelectrolytes are charged macromolecules, which are commonly found in natural science and engineering technology. However, because of the long range electrostatic interaction, the study of such systems has been a challenging and difficult problem in the field of soft matter. Among them, the adsorption of polyelectrolyte near the solid-liquid interface is an important problem in polymer physics. For example, the process can be used to enhance the stability of colloidal suspensions and serve as a model system for understanding protein-membrane interactions. Although polyelectrolyte adsorption has been extensively and deeply studied by soft matter physicists, the influence of charge modulation effect has been ignored in previous studies. Specifically, polyelectrolytes in aqueous environments gain charge through ionizable groups, and the degree of ionization depends not only on pH and salt concentration, but also on interactions with other charged objects, an effect known as charge modulation.

In this study, Jiaxing Yuan and his postdoctoral co-supervisor Professor Hajime Tanaka used a combination of Monte Carlo and molecular dynamics simulation methods to simulate the adsorption kinetics of polyelectrolytes. The method describes the multi-body coupling effect of material structure and charge state. Through numerical simulation, they discovered that the charge modulation effect can significantly enhance the adsorption of polyelectrolyte on the surface, and revealed the coupling mechanism between the adsorption structure and the charge state. Their study highlights the key role of charge modulation effects in polyelectrolyte adsorption, providing new insights into the prediction of protein adsorption capacity on biological surfaces.

Jiaxing said, "This study not only deepens the basic physical understanding of polyelectrolyte adsorption, but also its method can be widely applied to the simulation of solvation systems containing ionizable groups such as weak acids and weak bases. Proteins and DNA in the body are essentially charged polymer systems. It is hoped that this research could further prompt biophysicists to recognize the importance of charge modulation effects to more accurately characterize electrostatic interactions among biological macromolecules."

In the near future, Jiaxing will join Hong Kong University of Science and Technology (Guangzhou) as an Assistant Professor, and the research group will recruit doctoral students, master's students and undergraduates. Under the concept of "HKUST as One, the two universities complement each other", the Guangzhou campus and the Clear Water Bay Campus implement the same training model, research facilities and courses are open to each other, and the doctoral study duration is four years. The admitted students can get the internationally competitive full scholarship funding (10,000 / month for master students and 15,000 / month for doctoral students), and will be awarded the master/Doctor degree certificate of Hong Kong University of Science and Technology after graduation. Those who are interested in soft matter physics are welcome to contact Jiaxing Yuan alumni via email (yuan@g.ecc.u-tokyo.ac.jp).