An Optical Method for Quantitatively Determining the Surface Free Energy of Micro- and Nanoparticles
An Optical Method for Quantitatively Determining the Surface Free Energy of Micro- and Nanoparticles
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DOI：
10.1021/acs.analchem.9b02507
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发表时间：
2019-10-15
影响因子：
7.4
通讯作者：
Zuo, Yi Y.
中科院分区：
文献类型：
--
作者：
Cao, Zhenle;Tsai, Shannon Nicole;Zuo, Yi Y.
微米和纳米颗粒的表面自由能在决定颗粒的疏水性和润湿性方面起着至关重要的作用。然而，到目前为止，还没有简单易用的方法来确定颗粒的SFE。在这里，我们应用了几种廉价、易用和普遍可用的实验室方法和设备，包括粒子分散、沉降/离心法、移液和可见光光谱，我们开发了一种新的技术，称为最大粒子分散(MPD)方法，用于定量测定微米和纳米颗粒的SFE。我们通过研究9种不同化学成分、大小、尺寸和形态的具有代表性的颗粒，展示了MPD方法的通用性和稳健性。它们是三乙氧基辛基硅烷包裹的氧化锌纳米颗粒、多壁碳纳米管、石墨烯纳米小片、硫化钼(IV)片状、氧化钕纳米颗粒、两种尺寸的沸石、聚(乙烯基聚吡咯烷酮)和聚苯乙烯微粒。这些微米和纳米颗粒的超临界流体能量被发现覆盖范围从21到36 MJ/m(2)。这些超临界流体能值可能会在广泛的科学学科中找到应用，包括这些纳米材料的合成，例如在液体剥离中。MPD方法有可能发展成为一种标准的、低成本的、易于使用的方法，用于在微米和纳米尺度上定量表征颗粒的超临界流体力学和疏水性。
Surface free energy (SFE) of micro- and nanoparticles plays a crucial role in determining the hydrophobicity and wettability of the particles. To date, however, there are no easy-to-use methods for determining the SFE of particles. Here, with the application of several inexpensive, easy-to-use, and commonly available lab procedures and facilities, including particle dispersion, settling/centrifugation, pipetting, and visible-light spectroscopy, we developed a novel technique called the maximum particle dispersion (MPD) method for quantitatively determining the SFE of micro- and nanoparticles. We demonstrated the versatility and robustness of the MPD method by studying nine representative particles of various chemistries, sizes, dimensions, and morphologies. These are triethoxycaprylylsilane-coated zinc oxide nanoparticles, multiwalled carbon nanotubes, graphene nanoplatelets, molybdenum(IV) sulfide flakes, neodymium(III) oxide nanoparticles, two sizes of zeolites, poly(vinylpolypyrrolidone), and polystyrene microparticles. The SFE of these micro- and nanoparticles was found to cover a range from 21 to 36 mJ/m(2). These SFE values may find applications in a broad spectrum of scientific disciplines including the synthesis of these nanomaterials, such as in liquid-phase exfoliation. The MPD method has the potential to be developed into a standard, low-cost, and easy-to-use method for quantitatively characterizing the SFE and hydrophobicity of particles at the micro- and nanoscale.