title: Phase behavior of medium and high internal phase water-in-oil emulsions stabilized solely by hydrophobized bacterial cellulose nanofibrils.
abstract: Water-in-oil emulsions stabilized solely by bacterial cellulose nanofibers (BCNs), which were hydrophobized by esterification with organic acids of various chain lengths (acetic acid, C2-; hexanoic acid, C6-; dodecanoic acid, C12-), were produced and characterized. When using freeze-dried C6-BCN and C12-BCN, only a maximum water volume fraction (ϕw) of 60% could be stabilized, while no emulsion was obtained for C2-BCN. However, the maximum ϕw increased to 71%, 81%, and 77% for C2-BCN, C6-BCN, and C12-BCN, respectively, 150 h after the initial emulsification, thereby creating high internal phase water-in-toluene emulsions. The observed time-dependent behavior of these emulsions is consistent with the disentanglement and dispersion of freeze-dried modified BCN bundles into individual nanofibers with time. These emulsions exhibited catastrophic phase separation when ϕw was increased, as opposed to catastrophic phase inversion observed for other Pickering emulsions.
authors.affiliation: Polymer and Composite Engineering (PaCE) Group, Institute of Materials Chemistry and Research, Faculty of Chemistry, University of Vienna , Währinger Strasse 42, A-1090 Vienna, Austria.
authors.forename: Koon-Yang
authors.initials: KY
authors.lastname: Lee
authors.forename: Jonny J
authors.initials: JJ
authors.lastname: Blaker
authors.forename: Ryo
authors.initials: R
authors.lastname: Murakami
authors.forename: Jerry Y Y
authors.initials: JY
authors.lastname: Heng
authors.forename: Alexander
authors.initials: A
authors.lastname: Bismarck
mesh_terms: D001419:Bacteria / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D057139:Nanofibers / Q000737:chemistry*; D009821:Oils / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D004655:Emulsions; D009821:Oils; D014867:Water; D002482:Cellulose