Postdoctoral Appointee (Argonne National Lab), Visiting Scientist (University of Chicago)
5640 South Ellis Avenue
Eckhardt Research Laboratory 108
Chicago, IL 60637
Surface Forces of Polyelectrolyte Brushes: Understanding polyelectrolyte brush behavior has a great deal of practical interest in the realm of novel materials and interactions with physiological systems. In part, this interest is due to growing desire for polymeric materials, which can respond to changes in their environment. The polyelectrolyte brushes studied in this project are composed of the strong polyanion poly(sodium styrene sulfonate) and are highly responsive to changes in the ionic environment of their surrounding solution.
The Surface Forces Apparatus (SFA) measures forces between two surfaces coated with polyelectrolyte brushes. These force profiles provide both structural (i.e. polyelectrolyte brush height) and behavioral information of the polyelectrolyte brushes. When only mono-valent counterions are present, two brushes brought into contact interact in a repulsive manner. However, with the addition of multi-valent ions to the system, brushes readily collapse and adhere strongly to one another due to the fact that higher valence ions are able to neutralize multiple charges within the polyelectrolyte brushes.
Aside polyelectrolyte brushes, I am also interested in various interactions involved in polymeric systems, including the electrostatic interaction, structure forces, hydrophobic and hydration interactions, hydrogen bond, metal chelation, and specific ligand-acceptor interactions.
Jing Yu received his BS in Chemical Engineering from Tsinghua University. He received his Ph.D. from the Department of Chemical Engineering at University of California, Santa Barbara in 2012, where he worked in Professor Jacob Israelachvili's group. His Ph.D. work mostly focused on studying the adhesion mechanism of mussel adhesive proteins, the adhesion and friction of structured and rough surfaces, and the lubrication mechanism of human joints. From 2013-2014, he was a postdoctoral scholar in the Division of Chemistry and Chemical Engineering at California Institute of Technology. Jing joined the Institute for Molecular Engineering in 2014. His research interests includes (1) intermolecular and surface interactions of macromolecules (especially polyelectrolytes brushes) and membranes (2) developing polymer based functional materials, and (3) properties of materials under confinement.
- Multivalent counterions diminish the lubricity of polyelectrolyte brushes
- Multivalent ions induce lateral structural inhomogeneities in polyelectrolyte brushes
- Structure of polyelectrolyte brushes in the presence of multivalent counterions
- The effect of multivalent counterions on the structure of highly dense poly styrene sulfonate brushes