CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation , University of Science and Technology of China , Hefei 230026 , P.R. China.
School of Instrument Science and Optoelectronics Engineering , Hefei University of Technology , Hefei 230009 , P.R. China.
ACS Appl Mater Interfaces. 2018 May 16;10(19):16867-16873. doi: 10.1021/acsami.8b02812. Epub 2018 May 2.
We present here a kind of novel multiscale TiO square micropillar arrays on titanium sheets through vertically crossed scanning of femtosecond laser. This multiscale micro-/nanostructure is ascribed to the combination of laser ablation/shock compression/debris self-deposition, which shows superaerophobicity in water with a very small sliding angle. The laser-induced sample displays switchable bubble wettability in water via heating in a dark environment and ultraviolet (UV) irradiation in alcohol. After heating in a dark environment (0.5 h), the ablated titanium surface shows superaerophilicity in water with a bubble contact angle (BCA) of ∼4°, which has a great ability of capturing bubbles in water. After UV irradiation in alcohol (1 h), the sample recovered its superaerophobicity in water and the BCA turns into 156°. The mechanism of reversible switching is believed as the chemical conversion between Ti-OH and Ti-O. It is worth noting that our proposed switching strategy is time-saving and the switch wetting cycle costs only 1.5 h. Then we repeat five switching cycles on the reversibility and the method shows excellent reproducibility and stability. Moreover, laser-induced samples with different scanning spacing (50-120 μm) are fabricated and all of them show switchable underwater bubble wettability via the above tunable methods. Finally, we fabricate hybrid-patterned microstructures to show different patterned bubbles in water on the heated samples. We believe the original works will provide some new insights to researchers in bubble manipulation and gas collection fields.
我们在此提出了一种新颖的钛片上的 TiO 方微柱阵列多尺度结构，其通过飞秒激光的垂直交叉扫描形成。这种多尺度微/纳结构归因于激光烧蚀/冲击波压缩/碎片自沉积的结合，在水中表现出超疏水性，滑动角非常小。通过在黑暗环境中加热和在酒精中进行紫外线（UV）照射，激光诱导的样品在水中表现出可切换的气泡润湿性。在黑暗环境中加热（0.5 h）后，被烧蚀的钛表面在水中表现出超亲水性，气泡接触角（BCA）约为 4°，具有在水中捕获气泡的强大能力。在酒精中进行 UV 照射（1 h）后，样品恢复了在水中的超疏水性，BCA 变为 156°。可逆切换的机制被认为是 Ti-OH 和 Ti-O 之间的化学转化。值得注意的是，我们提出的切换策略省时省力，切换润湿循环仅需 1.5 h。然后，我们在可重复性方面重复了五次切换循环，该方法显示出优异的重现性和稳定性。此外，还制备了具有不同扫描间距（50-120 μm）的激光诱导样品，通过上述可调谐方法，所有样品均表现出可切换的水下气泡润湿性。最后，我们制作了混合图案微结构，在加热后的样品上展示了水中不同图案的气泡。我们相信，这项原创工作将为气泡操纵和气体收集领域的研究人员提供一些新的见解。
