Department of Electrical Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States.
ACS Appl Mater Interfaces. 2013 Jan;5(1):179-85. doi: 10.1021/am302357t. Epub 2012 Dec 17.
The applicability of gallium-based liquid metal alloy has been limited by the oxidation problem. In this paper, we report a simple method to remove the oxide layer on the surface of such alloy to recover its nonwetting characteristics, using hydrochloric acid (HCl) vapor. Through the HCl vapor treatment, we successfully restored the nonwetting characteristics of the alloy and suppressed its viscoelasticity. We analyzed the change of surface chemistry before and after the HCl vapor treatment using X-ray photoelectron spectroscopy (XPS) and low-energy ion-scattering spectroscopy (LEIS). Results showed that the oxidized surface of the commercial gallium-based alloy Galinstan (Ga(2)O(3) and Ga(2)O) was replaced with InCl(3) and GaCl(3) after the treatment. Surface tension and static contact angle on a Teflon-coated glass of the HCl-vapor-treated Galinstan were measured to be 523.8 mN/m and 152.5°. A droplet bouncing test was successfully carried out to demonstrate the nonwetting characteristics of the HCl-vapor-treated Galinstan. Finally, the stability of the transformed surface of the HCl-vapor-treated Galinstan was investigated by measuring the contact angle and LEIS spectra after reoxidation in an ambient environment.
镓基液态金属合金的适用性受到氧化问题的限制。在本文中，我们报告了一种简单的方法，使用盐酸（HCl）蒸气去除该合金表面的氧化层，以恢复其不润湿特性。通过 HCl 蒸气处理，我们成功地恢复了合金的不润湿特性并抑制了其粘弹性。我们使用 X 射线光电子能谱（XPS）和低能离子散射谱（LEIS）分析了 HCl 蒸气处理前后表面化学变化。结果表明，商用镓基合金 Galinstan（Ga2O3 和 Ga2O）的氧化表面在处理后被 InCl3 和 GaCl3 取代。HCl 蒸气处理后的 Galinstan 在涂覆特氟龙的玻璃上的表面张力和静态接触角分别为 523.8 mN/m 和 152.5°。成功进行了液滴弹跳测试，以证明 HCl 蒸气处理后的 Galinstan 的不润湿特性。最后，通过测量在环境气氛中重新氧化后的接触角和 LEIS 谱，研究了 HCl 蒸气处理后的 Galinstan 转化表面的稳定性。
