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Synthesis of pH-Responsive Inorganic Janus Nanoparticles and Experimental Investigation of the Stability of Their Pickering Emulsions
Langmuir ( IF 3.7 ) Pub Date : 2017-09-22 00:00:00 , DOI: 10.1021/acs.langmuir.7b02174
Wei Xue 1, 2 , Hengquan Yang 1 , Zhiping Du 3
Affiliation  

Pickering emulsions exhibit outstanding stability, especially those prepared with Janus particles, whose desorption energy is expected to be up to 3-fold greater than emulsions of homogeneous particles from theoretical calculations. To the best of our knowledge, however, there remains no experimental proof of this behavior in practice. In this study, inorganic Janus nanoparticles were fabricated by regioselective modification of the separate side of SiO2 nanoparticles with a judiciously selected mixture of trimethoxysilylpropyldiethylenetriamine and n-octyltrimethoxysilane. Janus nanoparticles demonstrated excellent interfacial activity, forming Pickering emulsions with oil phases at oil–water interfacial tensions ranging from 6.6–52.8 mN m–1. Furthermore, as the interface of the Janus nanoparticles was regionally functionalized with −NH2 groups, phase inversion could be realized by tuning pH. This is the first example for the Pickering emulsions stabilized with inorganic Janus particles. Importantly, based on the results of centrifugation experiment, the desorption energy of Janus nanoparticles at the interface was 3.2 times larger than that of homogeneous nanoparticles, which is in accordance with the result from theoretical calculations. These experimental results will substantially enrich our understanding of Janus nanoparticle Pickering emulsions and their interfacial assembly behavior.

中文翻译:

pH响应型无机Janus纳米粒子的合成及其吸乳剂稳定性的实验研究

Pickering乳液表现出出色的稳定性,尤其是用Janus颗粒制备的乳液,其脱附能预计比理论计算得出的均质颗粒乳液高3倍。据我们所知,在实践中,尚无实验证明这种行为。在这项研究中,通过明智选择的三甲氧基甲硅烷基丙基二亚乙基三胺和辛基三甲氧基硅烷的混合物对SiO 2纳米颗粒的另一面进行区域选择性修饰,制备了无机Janus纳米颗粒。Janus纳米粒子表现出出色的界面活性,在油水界面张力范围为6.6-52.8 mN m –1的情况下,形成具有油相的Pickering乳液。此外,由于Janus纳米颗粒的界面已被-NH 2基团局部官能化,因此可以通过调节pH来实现相转化。这是用无机Janus颗粒稳定的Pickering乳液的第一个例子。重要的是,基于离心实验的结果,Janus纳米粒子在界面处的解吸能量是均质纳米粒子的3.2倍,这与理论计算的结果相符。这些实验结果将大大丰富我们对Janus纳米Pickering乳液及其界面组装行为的理解。
更新日期:2017-09-23
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