title: Tuning the Wettability of Halloysite Clay Nanotubes by Surface Carbonization for Optimal Emulsion Stabilization.
abstract: The carbonization of hydrophilic particle surfaces provides an effective route for tuning particle wettability in the preparation of particle-stabilized emulsions. The wettability of naturally occurring halloysite clay nanotubes (HNT) is successfully tuned by the selective carbonization of the negatively charged external HNT surface. The positively charge chitosan biopolymer binds to the negatively charged external HNT surface by electrostatic attraction and hydrogen bonding, yielding carbonized halloysite nanotubes (CHNT) on pyrolysis in an inert atmosphere. Relative to the native HNT, the oil emulsification ability of the CHNT at intermediate levels of carbonization is significantly enhanced due to the thermodynamically more favorable attachment of the particles at the oil-water interface. Cryogenic scanning electron microscopy (cryo-SEM) imaging reveals that networks of CHNT attach to the oil-water interface with the particles in a side-on orientation. The concepts advanced here can be extended to other inorganic solids and carbon sources for the optimal design of particle-stabilized emulsions.
authors.forename: Olasehinde
authors.initials: O
authors.lastname: Owoseni
authors.forename: Yueheng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Su
authors.forename: Jibao
authors.initials: J
authors.lastname: He
authors.forename: Gary L
authors.initials: GL
authors.lastname: McPherson
authors.affiliation: Department of Chemical Engineering, University of Rhode Island , Kingston, Rhode Island 02881, United States.
authors.forename: Arijit
authors.initials: A
authors.lastname: Bose
authors.forename: Vijay T
authors.initials: VT
authors.lastname: John
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry; D000077215:Clay; D004655:Emulsions; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D017155:Wettability
chemical_list: D000538:Aluminum Silicates; D004655:Emulsions; D002244:Carbon; D048271:Chitosan; D000077215:Clay