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Tehseen Adel_2017MS thesisFinal.pdf (2.67 MB)

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Design, Construction, and Implementation of Ionization Method Surface Potential Instrument For Studies of Charged Surfactants and Inorganic Electrolytes At the Air/Water Interface

Adel, Tehseen
http://orcid.org/0000-0001-9869-0123
http://rave.ohiolink.edu/etdc/view?acc_num=osu1512122927166396

Abstract Details

2017, Master of Science, Ohio State University, Chemistry.
Surface potential is a valid and relevant macroscopic technique used to determine the orientation of water dipoles at the interface of air and water. In this work, an ionization based surface potential (SP) instrument is designed and configured. The first set of results are presented here. A custom designed americium-gold matrix foil with an activity of 20µCi and 9.5mm surface diameter is used as the air electrode suspended over a sample solution. A parallel aligned platinum gauze electrode is immersed in solution directly under the probe. The electrodes are connected to a Keithley 6517B electrometer. Subsequent measurements are made in the DC voltage mode of the electrometer for charged surfactants (SDS, CTAB) and inorganic electrolytes (NaCl, MgCl2, Na2SO4, MgSO4). The surface potential measurements were compared to studies by Nakahara et. al, (2005, 2008) and Jarvis and Scheiman (1968). The potentials measured for SDS showed linear increase from 1 to 5mM consistent with previous findings in that regime. A similar result is observed with CTAB in the 0.8-1mM concentration regime. The measured sign of the potentials is consistent with the sign of the surface charge for these molecules. For the inorganic salts, the surface potential difference is plotted versus concentration. Though the magnitude of these results does not fall within range of the Jarvis-Scheiman study, similar trends are observed. Positive trends are observed for Na2SO4 and MgSO4 and negative trends for NaCl and MgCl2. These results are compared to several MD simulation studies which show the surface propensity for ions and its effect on the electric double layer. The results of this study are key to validating observations of measurements using macroscopic techniques for air/water interface studies. Knowledge gained from these studies will provide insight into questions regarding multiple aqueous ion studies: atmospheric aerosol chemistry, thundercloud electrification, geochemistry, ocean surface processes, etc.
Heather Allen (Advisor)
Anne Co (Committee Member)
75 p.
Chemistry
surface potential; ionization method surface potential; soluble charged surfactants, aqueous electrolytes, air-water interface; physical chemistry;

Recommended Citations

Citations

  • Adel, T. (2017). Design, Construction, and Implementation of Ionization Method Surface Potential Instrument For Studies of Charged Surfactants and Inorganic Electrolytes At the Air/Water Interface [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512122927166396

    APA Style (7th edition)

  • Adel, Tehseen. Design, Construction, and Implementation of Ionization Method Surface Potential Instrument For Studies of Charged Surfactants and Inorganic Electrolytes At the Air/Water Interface. 2017. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1512122927166396.

    MLA Style (8th edition)

  • Adel, Tehseen. "Design, Construction, and Implementation of Ionization Method Surface Potential Instrument For Studies of Charged Surfactants and Inorganic Electrolytes At the Air/Water Interface." Master's thesis, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512122927166396

    Chicago Manual of Style (17th edition)

osu1512122927166396
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This open access ETD is published by The Ohio State University and OhioLINK.