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Particles at oil–air surfaces : powdered oil, liquid oil marbles, and oil foam

Binks, Bernard P.; Johnston, Shaun K.; Sekine, Tomoko; Tyowua, Andrew T.


Shaun K. Johnston

Tomoko Sekine

Andrew T. Tyowua


The type of material stabilized by four kinds of fluorinated particles (sericite and bentonite platelet clays and spherical zinc oxide) in air–oil mixtures has been investigated. It depends on the particle wettability and the degree of shear. Upon vigorous agitation, oil dispersions are formed in all the oils containing relatively large bentonite particles and in oils of relatively low surface tension (γla < 26 mN m⁻¹) like dodecane, 20 cS silicone, and cyclomethicone containing the other fluorinated particles. Particle-stabilized oil foams were obtained in oils having γla > 26 mN m⁻¹ where the advancing air–oil–solid contact angle θ lies between ca. 90° and 120°. Gentle shaking, however, gives oil-in-air liquid marbles with all the oil–particle systems except for cases where θ is <60°. For oils of tension >24 mN m⁻¹ with omniphobic zinc oxide and sericite particles for which advancing θ ≥ 90°, dry oil powders consisting of oil drops in air which do not leak oil could be made upon gentle agitation up to a critical oil:particle ratio (COPR). Above the COPR, catastrophic phase inversion of the dry oil powders to air-in-oil foams was observed. When sheared on a substrate, the dry oil powders containing at least 60 wt % of oil release the encapsulated oil, making these materials attractive formulations in the cosmetic and food industries.


Binks, B. P., Johnston, S. K., Sekine, T., & Tyowua, A. T. (2015). Particles at oil–air surfaces : powdered oil, liquid oil marbles, and oil foam. ACS Applied Materials & Interfaces, 7(26), 14328-14337.

Journal Article Type Article
Acceptance Date Jun 12, 2015
Online Publication Date Jun 24, 2015
Publication Date Jul 8, 2015
Deposit Date Jul 29, 2015
Publicly Available Date Nov 23, 2017
Journal ACS applied materials & interfaces
Print ISSN 1944-8244
Electronic ISSN 1944-8252
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 7
Issue 26
Pages 14328-14337
Keywords Dry oil, Oil foam, Liquid oil marbles, Surface energy, Omniphobicity
Public URL
Publisher URL
Additional Information This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS applied materials & interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see


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