Gel Electrophoresis of an Oil Drop
We present a theoretical model for the electrophoresis of a weakly charged oil drop migrating through an uncharged polymer gel medium saturated with an aqueous electrolyte solution. The surface charge of the drop arises from the specific adsorption of ions onto its interface. Unlike solid particles,...
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MDPI AG
2025-07-01
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| Series: | Gels |
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| Online Access: | https://www.mdpi.com/2310-2861/11/7/555 |
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| author | Hiroyuki Ohshima |
| author_facet | Hiroyuki Ohshima |
| author_sort | Hiroyuki Ohshima |
| collection | DOAJ |
| description | We present a theoretical model for the electrophoresis of a weakly charged oil drop migrating through an uncharged polymer gel medium saturated with an aqueous electrolyte solution. The surface charge of the drop arises from the specific adsorption of ions onto its interface. Unlike solid particles, liquid drops exhibit internal fluidity and interfacial dynamics, leading to distinct electrokinetic behavior. In this study, the drop motion is driven by long-range hydrodynamic effects from the surrounding gel, which are treated using the Debye–Bueche–Brinkman continuum framework. A simplified version of the Baygents–Saville theory is adopted, assuming that no ions are present inside the drop and that the surface charge distribution results from linear ion adsorption. An approximate analytical expression is derived for the electrophoretic mobility of the drop under the condition of low zeta potential. Importantly, the derived expression explicitly includes the Marangoni effect, which arises from spatial variations in interfacial tension due to non-uniform ion adsorption. This model provides a physically consistent and mathematically tractable basis for understanding the electrophoretic transport of oil drops in soft porous media such as hydrogels, with potential applications in microfluidics, separation processes, and biomimetic systems. These results also show that the theory could be applied to more complicated or biologically important soft materials. |
| format | Article |
| id | doaj-art-a16cb74897de4ac08ec7d252884ae773 |
| institution | DOAJ |
| issn | 2310-2861 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Gels |
| spelling | doaj-art-a16cb74897de4ac08ec7d252884ae7732025-08-20T02:45:46ZengMDPI AGGels2310-28612025-07-0111755510.3390/gels11070555Gel Electrophoresis of an Oil DropHiroyuki Ohshima0Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Chiba, JapanWe present a theoretical model for the electrophoresis of a weakly charged oil drop migrating through an uncharged polymer gel medium saturated with an aqueous electrolyte solution. The surface charge of the drop arises from the specific adsorption of ions onto its interface. Unlike solid particles, liquid drops exhibit internal fluidity and interfacial dynamics, leading to distinct electrokinetic behavior. In this study, the drop motion is driven by long-range hydrodynamic effects from the surrounding gel, which are treated using the Debye–Bueche–Brinkman continuum framework. A simplified version of the Baygents–Saville theory is adopted, assuming that no ions are present inside the drop and that the surface charge distribution results from linear ion adsorption. An approximate analytical expression is derived for the electrophoretic mobility of the drop under the condition of low zeta potential. Importantly, the derived expression explicitly includes the Marangoni effect, which arises from spatial variations in interfacial tension due to non-uniform ion adsorption. This model provides a physically consistent and mathematically tractable basis for understanding the electrophoretic transport of oil drops in soft porous media such as hydrogels, with potential applications in microfluidics, separation processes, and biomimetic systems. These results also show that the theory could be applied to more complicated or biologically important soft materials.https://www.mdpi.com/2310-2861/11/7/555gel electrophoresisgel electrophoretic mobilityoil dropliquid droppolymer gel mediumMarangoni effect |
| spellingShingle | Hiroyuki Ohshima Gel Electrophoresis of an Oil Drop Gels gel electrophoresis gel electrophoretic mobility oil drop liquid drop polymer gel medium Marangoni effect |
| title | Gel Electrophoresis of an Oil Drop |
| title_full | Gel Electrophoresis of an Oil Drop |
| title_fullStr | Gel Electrophoresis of an Oil Drop |
| title_full_unstemmed | Gel Electrophoresis of an Oil Drop |
| title_short | Gel Electrophoresis of an Oil Drop |
| title_sort | gel electrophoresis of an oil drop |
| topic | gel electrophoresis gel electrophoretic mobility oil drop liquid drop polymer gel medium Marangoni effect |
| url | https://www.mdpi.com/2310-2861/11/7/555 |
| work_keys_str_mv | AT hiroyukiohshima gelelectrophoresisofanoildrop |