When oppositely charged polymers are mixed in water, they form a polyelectrolyte complex. Analogously at a surface, oppositely charged polymers can be assembled to form a polyelectrolyte multilayer. These ion-pairing interactions are strongly sensitive to external phenomena (pH, ionic strength, etc.), making polyelectrolyte complexes and multilayers a highly tunable platform for applications ranging broadly from drug delivery and tissue engineering to smart coatings and sensors. This seminar will first present the effects of temperature on polyelectrolyte complexes and multilayers, which is currently not well understood. Evidence for a weak thermal transition will be discussed, in which polyelectrolyte complexes and multilayers undergo a dehydration event that triggers glass-transition-like behavior. Although the transition is weak, it stimulates large-scale macroscopic phenomena such as multilayer shrinking, swelling, and rearrangement. This seminar will next present the effects of water on the transition, in which the transition is dictated by disruption of the water-hydrogen-bonding network within the complex or multilayer. Finally salt-effects will be presented, in which monovalent and divalent ions are presented. These results indicate that this thermal transition may be in important handle for thermally responsive polyelectrolyte complexes or multilayers.
Jodie L. Lutkenhaus is an Associate Professor and William and Ruth Neely Faculty Fellow in the Artie McFerrin Department of Chemical Engineering at Texas A&M University. Lutkenhaus received her B.S. in Chemical Engineering in 2002 from The University of Texas at Austin and her Ph.D in Chemical Engineering in 2007 from Massachusetts Institute of Technology. Following a postdoctoral position at University of Massachusetts Amherst, she joined the faculty at Yale in 2008. In 2010, she moved to Texas A&M University and was promoted to Associate Professor in 2015.
Current research areas include polyelectrolytes, electroactive polymers, energy storage, and anti-corrosion coatings. She has received recognitions including the NSF CAREER, AFSOR YIP, 3M Non-tenured Faculty Award, ACS PRF Doctoral New Investigator, Kaneka Junior Faculty Scholarship, and an ACS PMSE Young Investigator.