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Title: Importance of hydrophobic traps for proton diffusion in lyotropic liquid crystals

The diffusion of protons in self-assembled systems is potentially important for the design of efficient proton exchange membranes. In this work, we study proton dynamics in a low-water content, lamellar phase of an sodium-carboxylate gemini surfactant/water system using computer simulations. The hopping of protons via the Grotthuss mechanism is explicity allowed through the multi-state empirical valence bond (MS-EVB) method. We find that the hydronium ion is trapped on the hydrophobic side of the surfactant-water interface, and proton diffusion then proceeds by hopping between surface sites. The importance of hydrophobic traps is surprising, because one would expect the hydronium ions to be trapped at the charged head-groups. Finally, the physics illustrated in this system should be relevant to the proton dynamics in other amphiphilic membrane systems, whenever there exists exposed hydrophobic surface regions.
 [1] ; ORCiD logo [1]
  1. Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
Publication Date:
Report Number(s):
NoneDOE-UWMadison-46938-4th product
Journal ID: ISSN 0021-9606; JCPSA6
Grant/Contract Number:
SC0010328; CHE-0840494
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 144; Journal Issue: 9; Journal ID: ISSN 0021-9606
American Institute of Physics (AIP)
Research Org:
Univ. of Wisconsin, Madison, WI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
08 HYDROGEN; 36 MATERIALS SCIENCE; molecular dynamics; membranes; proton transfer; proton transport; Grotthuss
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1240308; OSTI ID: 1341622