Phase Behavior of Medium and High Internal Phase Water-in-Oil Emulsions Stabilized Solely by Hydrophobized Bacterial Cellulose Nanofibrils

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• 作者：Koon-Yang Lee ; Jonny J. Blaker ; Ryo Murakami ; Jerry Y. Y. Heng ; Alexander Bismarck
• 刊名：Langmuir
• 出版年：2014
• 出版时间：January 21, 2014
• 年：2014
• 卷：30
• 期：2
• 页码：452-460
• 全文大小：419K
• ISSN：1520-5827

文摘

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 (_w) of 60% could be stabilized, while no emulsion was obtained for C₂-BCN. However, the maximum _w 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 _w was increased, as opposed to catastrophic phase inversion observed for other Pickering emulsions.