pH-responsive magnetic Pickering Janus emulsions
- We report ultrasonically generated pH-responsive Pickering Janus emulsions of olive oil and silicone oil with controllable droplet size and engulfment. Chitosan was used as a pH-responsive emulsifier. The increase of pH from 2 to 6 leads to a transition from completely engulfed double emulsion droplets to dumbbell-shaped Janus droplets accompanied by a significant decrease of droplet diameter and a more homogeneous size distribution. The results can be elucidated by the conformational change of chitosan from a more extended form at pH 2 to a more flexible form at pH 4-5. Magnetic responsiveness to the emulsion was attributed by dispersing superparamagnetic nanoparticles (Fe3O4 with diameter of 13 +/- 2 nm) in the olive oil phase before preparing the Janus emulsion. Incorporation of magnetic nanoparticles leads to superior emulsion stability, drastically reduced droplet diameters, and opened the way to control movement and orientation of the Janus droplets according to an external magnetic field.
Author details: | Rajarshi Roy RajuORCiDGND, Ferenc LiebigGND, Bastian KlemkeORCiD, Joachim KoetzORCiDGND |
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DOI: | https://doi.org/10.1007/s00396-018-4321-z |
ISSN: | 0303-402X |
ISSN: | 1435-1536 |
Title of parent work (English): | Colloid and polymer science : official journal of the Kolloid-Gesellschaft |
Publisher: | Springer |
Place of publishing: | New York |
Publication type: | Article |
Language: | English |
Date of first publication: | 2018/04/25 |
Publication year: | 2018 |
Release date: | 2021/11/30 |
Tag: | Chitosan; Cryo-SEM; Janus emulsion; Magnetic-responsive; TEM; pH-responsive |
Volume: | 296 |
Issue: | 6 |
Number of pages: | 8 |
First page: | 1039 |
Last Page: | 1046 |
Funding institution: | Polymer Science Program |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Peer review: | Referiert |