Abstract The wetting behavior of aluminum (0 0 1) and silicon ( 0 0 1 ¯ ) basal surfaces of metakaolinite was investigated by means of force-field molecular dynamics simulations. The rationality of existing controversial metakaolinite models was verified and the Brindley and Nakahira model was confirmed. Kaolinite has mainly hydrogen bonding between the layers, which is sufficiently strong to prevent cleavage under normal conditions. While under calcination, the dehydroxylation on kaolinite led to the weakening of interlayer attraction from hydrogen bonding to Van der Waals forces, caused the subsequent breakup of particle and the increase of specific surface area. It has been found that the calculated contact angle of metakaolinite aluminum surface was 17°, which is different to zero contact angle of kaolinite aluminum surface. The loss of inner-surface protons and hydroxyl ions resulted in unsaturated coordinated aluminum sheet, which was ready to react with dropping water to form new Al-Ow and hydroxyl bonds. Apparently, these water-clay interactions mechanisms played a major role in the different wettability of metakaolinite. For comparison purpose, contact angles for kaolinite and metakaolinite were measured by experiments, the measured values were and 20° and 41° respectively, the increase of contact angel had the benefit of the decreased hydrophilicity on aluminum surfaces of metakaolinite.

中文翻译：

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偏高岭石在基底表面的润湿行为——分子动力学研究

摘要 通过力场分子动力学模拟研究了偏高岭石的铝（0 0 1）和硅（ 0 0 1 ¯ ）基面的润湿行为。验证了现有有争议的偏高岭石模型的合理性，并证实了 Brindley 和 Nakahira 模型。高岭石层间主要有氢键，其强度足以防止正常条件下的裂解。在煅烧过程中，高岭石上的脱羟基导致氢键对范德华力的层间吸引力减弱，导致随后的颗粒破碎和比表面积增加。已经发现偏高岭土铝表面的计算接触角为17°，这与高岭土铝表面的零接触角不同。内表面质子和羟基离子的损失导致不饱和配位铝片，准备与滴水反应形成新的 Al-Ow 和羟基键。显然，这些水-粘土相互作用机制在偏高岭石的不同润湿性中起主要作用。为了对比，通过实验测量了高岭石和偏高岭石的接触角，测量值分别为20°和41°，接触角的增加有利于偏高岭石铝表面亲水性的降低。这些水-粘土相互作用机制在偏高岭石的不同润湿性中起主要作用。为了对比，通过实验测量了高岭石和偏高岭石的接触角，测量值分别为20°和41°，接触角的增加有利于偏高岭石铝表面亲水性的降低。这些水-粘土相互作用机制在偏高岭石的不同润湿性中起主要作用。为了对比，通过实验测量了高岭石和偏高岭石的接触角，测量值分别为20°和41°，接触角的增加有利于偏高岭石铝表面亲水性的降低。