Interdisciplinary Physics Seminar

Friday, 27 September 2013 at 11:30 am

Room 1400 Biomedical and Physical Sciences Bldg.

Refreshments at 11:15 am.

Speaker:  Heather Allen, Departments of Chemistry and Biochemistry, The Ohio State University

Title:  Ions, Lipids, and Water at the Air-Aqueous Interface: Organization and Electric Fields

Motivated by atmospheric aerosol chemistry of marine and urban regions, and biophysical applications related to lung lining and biomembranes, monovalent and divalent cations and anions were investigated using phase sensitive sum frequency generation (PS-SFG) spectroscopy to understand the surface propensity and availability for reaction at water surfaces. Ion valency, polarizability, size, shape, and identity of the counterion are critical factors in considering ion organization and subsequent changes in interfacial electric field at the air water interface. Phospholipids and fatty acids were also studied using both SFG and Brewster angle microscopy (BAM). Head group differences, especially with regard to hydrogen bonding capability and extent, are discerning factors for surface organization and shape distinction at the water surface.