Wu Junrui, Yin Kai, Li Ming, Wu Zhipeng, Xiao Si, Wang Hua, Duan Ji-An, He Jun
Hunan Key Laboratory of Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, 410083, China.
State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, Shaanxi 710119, China.
Nanoscale. 2020 Feb 14;12(6):4077-4084. doi: 10.1039/c9nr09902f. Epub 2020 Feb 5.
Self-driven and continuous directional transport of water droplets in an oil environment has great potential applications in microfluidics, oil-water separation, etc. Nevertheless, most current studies exploit water behaviors occurring in air, and the directional regulation of water in a viscous oil medium remains a challenge. In this work, a superhydrophilic geometry-gradient stainless steel platform with nanoparticle-covered nanoripple structures is proposed using femtosecond laser direct writing technology. The as-prepared platform spontaneously and directionally transported water droplets in the oil environment from the minor side to the large side of the trapezoidal platform surface, but not in the opposite direction. The transport velocity of water droplets as a function of trapezoid angle and tilt angle of the as-prepared platform was investigated in detail. In addition, a pumpless under-oil water transport platform was successfully prepared on other substrates including Ti and Ni sheets, polyimide film, and C cloth, and exhibited transport capabilities when the platform was flexed and combined into various shapes. This work offers insight into the simple fabrication of a flexible and substrate-independent pumpless under-oil directional transport device for water.
在油环境中，水滴的自驱动连续定向传输在微流控、油水分离等领域具有巨大的潜在应用价值。然而，目前大多数研究关注的是空气中水的行为，而在粘性油介质中对水进行定向调控仍然是一个挑战。在这项工作中，利用飞秒激光直写技术，提出了一种具有纳米颗粒覆盖的纳米波纹结构的超亲水几何梯度不锈钢平台。所制备的平台能使油环境中的水滴在梯形平台表面从短边向长边自发地定向传输，但不能反向传输。详细研究了水滴的传输速度与所制备平台的梯形角度和倾斜角度之间的关系。此外，还成功地在包括钛片、镍片、聚酰亚胺薄膜和C布在内的其他基底上制备了无泵油下水传输平台，并且当平台弯曲并组合成各种形状时，该平台仍表现出传输能力。这项工作为简单制造一种灵活且与基底无关的无泵油下水分向传输装置提供了思路。
