Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu str. 56, LT-51424 Kaunas, Lithuania.
Sensors (Basel). 2020 Jul 9;20(14):3833. doi: 10.3390/s20143833.
A concept of a nanoporous anodic aluminum oxide (AAO) membrane as a vibro-active micro/nano-filter in a micro hydro mechanical system for the filtration, separation, and manipulation of bioparticles is reported in this paper. For the fabrication of a nanoporous AAO, a two-step mild anodization (MA) and hard anodization (HA) technique was used. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to analyze the surface morphology of nanoporous AAO. A nanoporous structure with a pore diameter in the range of 50-90 nm, an interpore distance of 110 nm, and an oxide layer thickness of 0.12 mm with 60.72% porosity was obtained. Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDS) were employed to evaluate AAO chemical properties. The obtained results showed that the AAO structure is of hexagonal symmetry and showed where AlO is dominant. The hydrophobic properties of the nanoporous surface were characterized by water contact angle measurement. It was observed that the surface of the nanoporous AAO membrane is hydrophilic. Furthermore, to determine whether a nanomembrane could function as a vibro-active nano filter, a numerical simulation was performed using COMSOL Multiphysics 5.4 (COMSOL Inc, Stockholm, Sweden). Here, a membrane was excited at a frequency range of 0-100 kHz for surface acoustics wave (SAW) distribution on the surface of the nanoporous AAO using a PZT 5H cylinder (Piezo Hannas, Wuhan, China). The SAW, standing acoustic waves, and travelling acoustic waves of different wavelengths were excited to the fabricated AAO membrane and the results were compared with experimental ones, obtained from non-destructive testing method 3D scanning vibrometer (PSV-500-3D-HV, Polytec GmbH, Waldbronn, Germany) and holographic interferometry system (PRISM, Hy-Tech Forming Systems (USA), Phoenix, AZ, USA). Finally, a simulation of a single nanotube was performed to analyze the acoustic pressure distribution and time, needed to center nanoparticles in the nanotube.
本文报道了一种将纳米多孔阳极氧化铝（AAO）膜用作微机电系统中振动活性微/纳米过滤器的概念，用于生物颗粒的过滤、分离和操作。为了制备纳米多孔 AAO，采用了两步温和阳极氧化（MA）和硬质阳极氧化（HA）技术。原子力显微镜（AFM）和扫描电子显微镜（SEM）用于分析纳米多孔 AAO 的表面形态。获得了具有 50-90nm 孔径、110nm 孔间距和 0.12mm 氧化层厚度的纳米多孔结构，其孔隙率为 60.72%。傅里叶变换红外光谱（FTIR）和能谱（EDS）用于评估 AAO 的化学性质。得到的结果表明，AAO 结构具有六方对称性，并且 AlO 占主导地位。纳米多孔表面的疏水性通过水接触角测量来表征。观察到纳米多孔 AAO 膜的表面是亲水的。此外，为了确定纳米膜是否可以用作振动活性纳米过滤器，使用 COMSOL Multiphysics 5.4（COMSOL Inc，斯德哥尔摩，瑞典）进行了数值模拟。在这里，使用 PZT 5H 圆柱（Piezo Hannas，武汉，中国）在 0-100kHz 的频率范围内激励膜，在纳米多孔 AAO 的表面上分布表面声波（SAW）。激发不同波长的 SAW、驻波和行波到制备的 AAO 膜上，并将结果与使用非破坏性测试方法 3D 扫描测振仪（PSV-500-3D-HV，Polytec GmbH，Waldbronn，德国）和全息干涉系统（PRISM，Hy-Tech Forming Systems（美国），凤凰城，亚利桑那州，美国）获得的实验结果进行比较。最后，对单个纳米管进行了模拟，以分析纳米管中纳米颗粒的声压分布和时间。
