液体在颗粒表面表观接触角的测量方法研究

发布时间：2018-04-04 15:37

本文选题：颗粒　切入点：接触角　出处：《山东建筑大学》2016年硕士论文

【摘要】：颗粒型材料被广泛地应用于很多领域。颗粒材料表面润湿性能会极大地影响界面性能及整体性能。接触角是表征液体在固体材料表面的润湿性及自由能的重要物理量,因此对接触角测量的研究无论是在材料研究还是应用都有重要意义。目前,对接触角的测量多限于具有光滑平面的固体材料,而对于表面既不光滑也不平整的颗粒型固体,液体在其固体表面表观接触角的测量相对比较困难。通过研究发现,颗粒堆积型多孔介质中,液体形态及分布发生变化时所对应的临界含湿率是由液体在颗粒表面的表观接触角决定。鉴于此,本文以建立的临界含湿率与接触角关系模型为基础,通过确定其临界含湿率,进而确定液体在颗粒表面的表观接触角。临界含湿率的确定通过显微观测实验和电导率测量实验这两种方法实现。通过显微观测实验,分析颗粒堆积而成的多孔介质内液体形态及分布随含湿率的变化,进而确定其临界含湿率。通过研究分析发现,非导电颗粒堆积多孔介质的导电性能与介质内导电液体的形态及分布密切相关,因此对于颗粒堆积形成的多孔介质内液体形态不易观测的情况,若颗粒本身不导电而液体导电,则可通过测量电导率方法确定临界含湿率。选用具有光滑平面且不导电的平板玻璃和载玻片进行接触角的测量后,对其进行破碎并获得不同粒径范围的破碎玻璃颗粒,作为堆积颗粒型多孔介质试样。在不同液相介质条件下,分别对不同含湿率下时不同颗粒试样的电导率及体积变化率进行实验测量,在此基础上确定临界含湿率。结合测量得到的液体在玻璃或载玻片上的接触角,对接触角与临界含湿率关系式进行了验证。由此,本文获得了测定颗粒型固体表面接触角的测量方法。选用不同粒径范围且不导电的沙粒堆积形成的颗粒型试样,测量不同液体在其表面的接触角。通过实验测量不同含湿率、不同粒径试样的表观体积变化率,并利用电导率及CCD显微观测共同确定临界含湿率。结合接触角与临界含湿率的关系式并进行相应的数据处理,得到的不同液体在沙粒表面的接触角。
[Abstract]:Granular materials are widely used in many fields.The surface wettability of granular materials will greatly affect the interfacial properties and overall properties.Contact angle is an important physical quantity to characterize the wettability and free energy of liquid on the surface of solid materials.At present, the measurement of contact angle is limited to the solid material with smooth plane, but it is relatively difficult to measure the apparent contact angle of liquid on the solid surface for granular solids whose surfaces are neither smooth nor smooth.It is found that the critical moisture content corresponding to the change of liquid morphology and distribution in granular packed porous media is determined by the apparent contact angle of liquid on the particle surface.In view of this, based on the established model of critical moisture content and contact angle, the apparent contact angle of liquid on particle surface is determined by determining its critical moisture content.The determination of critical moisture content is realized by two methods: microscopic observation experiment and conductivity measurement experiment.The changes of liquid morphology and distribution with moisture content in porous media formed by particles were analyzed by microscopic observation, and the critical moisture content was determined.Through research and analysis, it is found that the conductivity of non-conductive granular stacked porous media is closely related to the morphology and distribution of conductive liquid in the medium, so it is difficult to observe the liquid morphology in porous media formed by particle stacking.If the particle itself is not conductive and the liquid is conducting, the critical moisture content can be determined by measuring the conductivity.After measuring the contact angle of flat glass and glass slide with smooth plane and non-conductive surface, the broken glass particles with different particle sizes were obtained, which were used as the sample of piling granular porous media.The electrical conductivity and volume change rate of different particle samples with different moisture content were measured under different liquid medium conditions, and the critical moisture content was determined on the basis of these measurements.The relation between the contact angle and the critical moisture content of the liquid on glass or glass slide is verified.Therefore, a method for measuring the contact angle of granular solid surface is obtained.The contact angles of different liquids on the surface were measured by using granular samples with different particle size range and non-conductive sand accumulation.The apparent volume change rate of samples with different moisture content and particle size was measured by experiments, and the critical moisture content was determined by electrical conductivity and CCD microscopic observation.According to the relation between contact angle and critical moisture content and corresponding data processing, the contact angles of different liquids on sand surface are obtained.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB302

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