Kai Hiroyuki, Toyosato Ryoma, Nishizawa Matsuhiko
Department of Finemechanics, Tohoku University 6-6-1 Aramaki-Aoba Sendai Japan 980-8579
RSC Adv. 2018 Apr 30;8(29):15985-15990. doi: 10.1039/c8ra02655f. eCollection 2018 Apr 27.
A flexible polymer film was coated with titanium oxide and a fluoroacrylate polymer to make the surface superhydrophobic and then patterned with superhydrophilic open microfluidic channels consisting of fractal branching structures. The lateral transport of liquid driven by the imbalance of the Laplace pressure in the flow channels with a width gradient allowed the collection of tiny aqueous droplets from the entire surface of the film at the converging point at the center within a second. The proposed fractal patterns were well-defined (, mathematically determined in a unique manner) space-filling trees with only a few geometrical parameters. With the optimized geometrical parameters, the fluid volume collected to the film center (2.0 mm radius, 7.3% of total pattern area) reached 74% ± 9%, where the areal density of liquid was 12 times higher than that of an unpatterned surface.
一种柔性聚合物薄膜被涂上二氧化钛和氟丙烯酸酯聚合物，使表面具有超疏水性，然后用由分形分支结构组成的超亲水开放微流控通道进行图案化处理。在具有宽度梯度的流动通道中，由拉普拉斯压力不平衡驱动的液体横向传输，使得能在一秒内于薄膜整个表面的汇聚点（位于中心）收集到微小的水滴。所提出的分形图案是定义明确（以独特方式通过数学确定）的空间填充树，仅具有几个几何参数。通过优化的几何参数，收集到薄膜中心（半径2.0毫米，占总图案面积的7.3%）的流体体积达到74%±9%，此时液体的面密度比未图案化表面高12倍。
