A Semi-Automated Technique for Repeatable and Reproducible Contact Angle Measurements in Granular Materials using the Sessile Drop Method
A Semi-Automated Technique for Repeatable and Reproducible Contact Angle Measurements in Granular Materials using the Sessile Drop Method
复制标题
使用座滴法对颗粒材料进行可重复和可再现接触角测量的半自动化技术
DOI：
10.2136/sssaj2016.04.0131
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发表时间：
2017
影响因子：
2.9
通讯作者：
B. Baudet
中科院分区：
文献类型：
--
作者：
Y. Saulick;S. Lourenço;B. Baudet
接触角（CA）用于测量材料被润湿的程度。颗粒状材料，如天然土壤和粉碎的矿物，通常被认为是湿的，可以表现出非润湿特性。座滴法（SDM）是广泛用于产生和测量CA的直接方法，然而，其测定中涉及的程序常常被忽视，导致其测量中的非常大的标准偏差。在这项研究中，在颗粒状材料上提取CA所涉及的步骤的仔细检查表明，两个因素，图像曝光和基线的位置，可以显着影响CA测量。比较了7种CA拟合方法。结果发现，随着CA的增加，方法之间的差异变得越来越显着。因此，通过这项研究提出了一种半自动化的技术，以提高标准偏差的CA测量。新技术使用五个步骤，包括调整图像曝光和手动移动基线。所提出的方法在平坦表面以及颗粒材料（化学处理的沙子和天然存在的疏水矿物）上进行了测试。结果表明，该方法可以适用于平板和颗粒材料与广泛的CA。特别地，平坦表面的标准偏差（例如，疏水化的显微镜载玻片）与CA在90至135°范围内记录了37%的改善。对于粒状材料（例如，氟石）与CA在105至120°的范围内，已观察到标准偏差的33%的改进。
Contact angles (CAs) are used to measure the extent to which a material is wettable. Granular materials such as natural soils and crushed minerals, which are commonly assumed wettable, can exhibit non-wetting characteristics. The sessile drop method (SDM) is a direct method widely used to generate and measure CAs, however, the procedure involved in their determination is often overlooked leading to very large standard deviations in their measurements. In this study, a close examination of the steps involved in extracting the CAs on granular materials shows that two factors, the image exposure and the position of the baseline, can affect CAs measurements significantly. Seven methods of fitting CAs were compared. It was found that the discrepancy between the methods became more and more significant as CAs increase in magnitude. A semi-automated technique has therefore been proposed through this study to improve the standard deviations of CAs measurements. The new technique uses five steps and involves an adjustment of the image exposure and manual movement of the baseline. The proposed method was tested on flat surfaces as well as granular materials (chemically treated sand and a naturally occurring hydrophobic mineral). The results have shown that the method can be applied for both flat and granular materials with a wide range of CAs. In particular, the standard deviations of flat surfaces (e.g., hydrophobized microscope slides) with CA in the range of 90 to 135° recorded improvements of 37%. For granular materials (e.g., fluorspar) with CA in the range of 105 to 120°, improvements of 33% in standard deviations have been observed.