The value of the surface charge density of polypropylene reported in literature has
a three order of magnitude discrepancy. Nauruzbayeva et al report a 0.7nCcm−2
as the surface charge density of polypropylene as measured using the charge
of electrified droplets[1]. Meagher and Craig reported result 111nCcm−2 as estimated
by electric double layer theory from colloidal probe Atomic force microscopy
(AFM) force spectroscopy [2]. We show that oxidation of hydrophobic
surfaces as a potential mechanism in origin of these surface charges. Using
colloidal probe AFM We measured the surface charge densities of Teflon AF,
perfluorodecanethiol, Perfluorodecyltrichlorosilane(FDTS), Octadecyltrichlorosilane,
polystyrene, and polypropylene. Also, The pH dependence of the surface
charge density for FDTS was studied and it shows the behavior expected of a
weak acid in response to pH. We suspect that the origin of the surface charges
is mostly likely impurities or surface oxidation. We conclude that the electrometer
and dispensed droplets approach cannot detect these charges because of the
process of de-wetting all the surface be neutralized to maintain charge neutrality.
This explanation supports Nauruzbayeva et al claims about surface bound
charges[1].
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/693565 |
| Date | 07 1900 |
| Creators | Alghonaim, Abdulmalik |
| Contributors | Mishra, Himanshu, Physical Science and Engineering (PSE) Division, Fatayer, Shadi P., Daniel, Dan |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | 2024-08-14, At the time of archiving, the student author of this thesis opted to temporarily restrict access to it. The full text of this thesis will become available to the public after the expiration of the embargo on 2024-08-14. |
| Relation | N/A |
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