title: Polymer grafted hard carbon microspheres at an oil/water interface.
abstract: Pickering emulsions offer an established method of stabilizing oil-in-water emulsions as either an alternative to surfactants or as an additive together with surfactants, providing greater colloidal stability even at low particle concentrations. This work presents a novel experimental approach to study the influence of several system parameters on the effectiveness of Pickering emulsion systems. Specifically, a dodecane oil drop stabilized by hard carbon microspheres in an aqueous saline solution is used as a model system to obtain both quantitative and qualitative information on the effectiveness of the microspheres as a function of their surface wetting properties. The test setup, in which a macroscopic oil drop is brought into contact with a test surface in a controlled motion and environment, allows for several aspects of the test (for e.g., oil drop size, approach velocity, normal force, solution ionic strength, temperature, pH, and presence of surfactants) to be potentially controlled and studied precisely. To demonstrate the capabilities of the experimental set-up, hard carbon microspheres are modified with a poly(styrenesulfonate) shell through ATRP in order to tune the wettability of the particles through choice of polymer, which are then used to stabilize a dodecane oil drop in an aqueous saline solution. The particles effectively form a steric barrier preventing the spreading of an oil drop on hydrophobic surfaces and also preventing the coalescence of stabilized oil drops.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Cremaldi
authors.affiliation: Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ejaz
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, USA.
authors.forename: Shreyas
authors.initials: S
authors.lastname: Oak
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, USA.
authors.forename: Mary K
authors.initials: MK
authors.lastname: Holleran
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Roberts
authors.affiliation: Research Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang 212013, China.
authors.forename: Guanggui
authors.initials: G
authors.lastname: Cheng
authors.affiliation: Jiangsu Collaborative Innovation Center for Photovoltaic Science and Engineering, Jiangsu Province Cultivation Base for State Key Laboratory of Photovoltaic Science and Technology, Changzhou University, Changzhou, 213164 Jiangsu, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Grayson
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, USA.
authors.forename: Vijay
authors.initials: V
authors.lastname: John
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, USA. Electronic address: npesika@tulane.edu.
authors.forename: Noshir S
authors.initials: NS
authors.lastname: Pesika
keywords: Carbon microspheres; Pickering emulsion; Polymer ATRP; Steric repulsion; Wettability