EPFL BioE Talks SERIES "Exploring the Binding of Ions to Polymers in Aqueous Salt Solutions"


Event details

Date 26.09.2022
Hour 16:0017:00
Speaker Prof. Paul S. Cremer, Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA (USA)
Location Online
Category Conferences - Seminars
Event Language English

Hofmeister series chemistry has been a focus of both fundamental and industrial interest since it was first discovered over 130 years ago. It can be shown that a wide variety of physical phenomena follow a recurring rank ordering for both cations and anions when water, organic molecules and salts are mixed. Examples include the hydrophobic collapse and aggregation of macromolecules, the turnover rate of enzymes, the pickling of cucumbers, and even the transfer of charge between ice particles in a lightning storm. Using a combination of spectroscopic techniques, thermodynamic measurements as well as simulations, it is now possible to elucidate key molecular level details of Hofmeister series behavior. In this presentation, the solubility of thermoresponsive polymers in the presence of salts will be discussed. The results show that weakly hydrated anions bind along polymer chains in locations where the hydrogen bonding is most greatly disrupted. Curiously, this makes shorter oligomers less soluble compared to longer polymers possessing the same chemical constituents. Moreover, weakly hydrated anions interact more strongly than cations with uncharged polymer chains. In fact, metal cations rarely come to the polymer/water interface without being accompanied by counter anions.

1. Weakly hydrated anions bind to polymers but not monomers in aqueous solutions
Bradley A. Rogers, Halil I. Okur, Chuanyu Yan, Tinglu Yang, Jan Heyda, Paul S. Cremer
Nat. Chem. 14 (2022), 40-45
2. The Molecular Mechanism for the Interactions of Hofmeister Cations with Macromolecules in Aqueous Solution
Ellen E. Bruce, Halil I. Okur, Sina Stegmaier, Chad I. Drexler, Bradley A. Rogers, Nico F. A. van der Vegt, Sylvie
Roke, Paul S. Cremer
J. Am. Chem. Soc., 142 (2020) 19094-19100

Paul S. Cremer is the J. Lloyd Huck Chair in Natural Sciences at the Pennsylvania State University where he holds appointments in both the Department of Chemistry and the Department of Biochemistry and Molecular Biology. Prof. Cremer received his undergraduate degree from the University of Wisconsin – Madison (1990) and his Ph.D. from the University of California - Berkeley (1996) working with Prof. Gabor A. Somorjai as his thesis advisor.  He spent two years as the Irving S. Sigal Postdoctoral Fellow at Stanford University in the laboratory of Steven G. Boxer before starting his independent research career at Texas A&M University in 1998. He stayed at A&M for over 14 years, where he was named Distinguished Professor in 2012. The following year his laboratory moved to Penn State. He is a fellow of the American Association for the Advancement of Science as well as of the American Chemical Society. In 2017, he was named a Langmuir Lecturer by the ACS.  His group works at the cross-roads of physical chemistry, biological chemistry, materials science, and analytical chemistry.

Zoom link (with one-time registration for the whole series) for attending remotely: https://go.epfl.ch/EPFLBioETalks

Instructions for 1st-year Ph.D. students who are under EDBB’s mandatory seminar attendance rule:
IF you are not attending in-person in the room, please make sure to
  1. send D. Reinhard a note before noon on seminar day, informing that you plan to attend the talk online, and
  2. be signed in on Zoom with a recognizable user name (not a pseudonym making it difficult or impossible to be identified).
Students attending the seminar in-person should collect a confirmation signature after the talk - please print your own signature sheet beforehand (71 kB pdf available for download here).


Practical information

  • Informed public
  • Registration required