The ability of a surface to completely absorb a liquid droplet is an important property that can be controlled by geometrical structure and chemical composition of the surface. Here, using Laplace pressure and Gibbs free energy (GFE) considerations, a capped truncated microcone array geometry is proposed to obtain a near zero degree for contact angle (θ) of a water droplet. Our results showed that two essential conditions must be met to achieve a superabsorbent surface. First, negative Laplace pressure and, second, absence of a relative minimum in the plot of GFE versus contact angle. To investigate the effect of surface tension on the wettability, capped truncated microcone array films were prepared on Si (100) substrate using a lithography method. To validate the proposed geometry as a super water-absorbent surface, we compared theoretical calculations with the experimental results. Our theoretical and experimental studies show that the capped truncated SiO₂ microcone array film is a superabsorbent surface with nearly zero contact angle. The amount of 130° ± 3 was measured for the water contact angle of the capped truncated Si microcone array in the hydrophobic state, which is very close to the calculated water contact angle using the minimum of GFE (126.1°). Results proved that the predicted water contact angles are in very good agreement with the experimental measurements.

中文翻译：

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高吸水剂加帽截短二氧化硅微锥阵列：制造和扩展拉普拉斯压力和吉布斯自由能研究


表面完全吸收液滴的能力是一个重要的特性，可以通过表面的几何结构和化学成分来控制。在这里，利用拉普拉斯压力和吉布斯自由能 （GFE） 的考虑，提出了一种加帽截断微锥阵列几何结构，以获得水滴接触角 （θ） 的接近零度。我们的结果表明，要获得高吸水性表面，必须满足两个基本条件。首先，拉普拉斯负压，其次，GFE 与接触角的关系图中没有相对最小值。为了研究表面张力对润湿性的影响，使用光刻方法在 Si （100） 衬底上制备了加帽截短微锥阵列薄膜。为了验证所提出的几何形状是超级吸水表面，我们将理论计算与实验结果进行了比较。我们的理论和实验研究表明，加帽截短的 SiO₂ 微锥阵列薄膜是一种接触角几乎为零的高吸水性表面。在疏水状态下，测量了加帽截短 Si 微锥阵列的水接触角 130° ± 3，该接触角非常接近使用最小 GFE （126.1°） 计算的水接触角。结果证明，预测的水接触角与实验测量结果非常吻合。