【兴大报告 Xing Da Lecture 545】

题  目：Electrostatics beyondPoisson-Boltzmann: Effects of Self-Energy

报告人: Prof. Zhen-GangWang

Divisionof Chemistry and Chemical Engineering

California Institute of Technology

时　间：2018年5月11日(星期五)下午2:00

地　点：化学楼A204/206

主请人：陈尔强

报告摘要：

Ionsare essential in physical chemistry, colloidal science, electrochemistry,biology and many other areas of science and engineering.  Whiletheir role is commonly described in terms of screening and translationalentropy, many phenomena, ranging from some classical experimental observationsmade many decades ago to some new systems of current interest, cannot beexplained, even qualitatively, by these concepts.  A key effect that is often ignored orinadequately treated in the main literature on electrolytes and polyelectrolytesis the self-energy of the ions.  In this talk, I will discussseveral self-energy effects in macromolecular and interfacial systems.   First, we show that the preferentialsolvation energy of the ions provides a significant driving force for phaseseparation.  This conceptis used to develop a theory to explain the dramatic shift in the order-disordertransition temperature in PEO-PS diblock copolymers upon the addition ofsalt.  Second, we show that thedielectric contrast between the polymer backbone and the solvent significantlyaffects the conformation and charge condensation in dilute polyelectrolytesolutions.  Third, we show that the imageforce has qualitative effects on the double layer structure and forces, such aslike charge attraction and charge inversion. Finally we present a simple theoryfor treating charge correlation effects in polyelectrolyte solutions thatself-consistently account for the conformation changes of the polyelectrolytechains.