Salt-Resistant Switchable Pickering Emulsions Stabilized by Mesoporous Nanosilica Hydrophobized In Situ by pH-Insensitive Surfactants
Salt-Resistant Switchable Pickering Emulsions Stabilized by Mesoporous Nanosilica Hydrophobized In Situ by pH-Insensitive Surfactants
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由 pH 不敏感表面活性剂原位疏水化的介孔纳米二氧化硅稳定的耐盐可切换 Pickering 乳液
DOI：
10.1021/acs.langmuir.1c00231
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发表时间：
2021
期刊：
影响因子：
3.9
通讯作者：
Song Binglei
中科院分区：
文献类型：
--
作者：
Xie Danhua;Jiang Yulong;Zhang Yunjin;Song Binglei
以介孔纳米二氧化硅和pH不敏感的阳离子表面活性剂为稳定剂，制备了对酸碱敏感的新型水包油(O/W)Pickering乳液(PES)。加入适量的氢氧化钠(nNaOH/阳离子表面活性剂≥-1)可在10 S内迅速破乳，再加入盐酸溶液(nHCl/nNaOH=1)，均质后形成稳定的PES。这些乳液在60次循环后保持稳定30天以上，从稳定到不稳定再回到稳定状态，表现出很高的耐盐性。推导了Pickering乳液(PE)向不稳定状态和返回稳定状态转变的机理，其中包括介孔二氧化硅纳米颗粒(MSNPs)介孔上羟基的阴离子和中性形式。这项工作揭示了一种可切换的PE体系，其中包含对pH不敏感的表面活性剂，其中油和阳离子表面活性剂的种类可以任意选择，这一特点大大扩展了PE的适用性。
Novel oil-in-water (O/W) Pickering emulsions (PEs) were prepared using mesoporous nanosilica in combination with a pH-insensitive cationic surfactant as a stabilizer and show an interesting sensitivity to acids and bases. Adding a suitable amount of NaOH (nNaOH/ncationic surfactant≥ 1) led to prompt demulsification within 10 s. Upon further adding HCl solutions (nHCl/nNaOH= 1), stable PEs re-formed after homogenization. These emulsions remained stable for over 30 days after 60 cycles, switching from stable to unstable and back to stable states, and showed a high salt tolerance. A mechanism for the switching of the Pickering emulsion (PE) to unstable and back to stable states was derived and involved anionic and neutral forms of hydroxyl groups at the mesopores of the mesoporous silica nanoparticles (MSNPs). This work reveals a switchable PE system involving a pH-insensitive surfactant, in which the species of oils and cationic surfactants can be arbitrarily selected, a feature that greatly expands the applicability of PEs.