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

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

Abstract

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.

Citation

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. https://doi.org/10.1021/acsami.5b02890

• 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
• DOI: https://doi.org/10.1021/acsami.5b02890
• Keywords: Dry oil, Oil foam, Liquid oil marbles, Surface energy, Omniphobicity
• Public URL: https://hull-repository.worktribe.com/output/377172
• Publisher URL: http://pubs.acs.org/doi/abs/10.1021/acsami.5b02890
• 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 http://pubs.acs.org/doi/abs/10.1021/acsami.5b02890