Feng Xinjian, Roy Somnath C, Grimes Craig A
217 Materials Research Laboratory, Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA.
Langmuir. 2008 Apr 15;24(8):3918-21. doi: 10.1021/la703572z. Epub 2008 Feb 29.
Air bubbles are known to form at the liquid/solid interface of hydrophobic materials upon immersion in a liquid (Holmberg, M.; Kdühle, A.; Garnaes, J.; Mørch, K. A.; Boisen, A. Langmuir 2003, 19, 10510-10513). In the case of gravimetric sensors, air bubbles that randomly form at the liquid-solid interface result in poor sensor-to-sensor reproducibility. Herein a superhydrophilic ZnO nanorod film is applied to the originally hydrophobic surface of a resonance-based magnetoelastic sensor. The superhydrophilic coating results in the liquid completely spreading across the surface, removing unwanted air bubbles from the liquid/sensor interface. The resonance amplitude of uncoated (bare) and ZnO-modified sensors are measured in air and then when immersed in saline solution, ethylene glycol, or bovine blood. In comparison to the bare, hydrophobic sensors, we find that the standard deviation of the resonance amplitudes of the liquid-immersed ZnO-nanorod-modified sensors decreases substantially, ranging from a 27% decrease for bovine blood to a 67% decrease for saline. The strategy of using a superhydrophilic coating can be applied to other systems having similar interfacial problems.
众所周知，当疏水材料浸入液体中时，会在液/固界面形成气泡（霍尔姆贝格，M.；屈勒，A.；加尔奈斯，J.；莫尔克，K. A.；博伊森，A.《朗缪尔》2003年，第19卷，第10510 - 10513页）。对于重量传感器而言，在液固界面随机形成的气泡会导致传感器之间的重现性较差。在此，将超亲水的ZnO纳米棒薄膜应用于基于共振的磁弹性传感器原本疏水的表面。这种超亲水涂层使液体完全铺展在表面，从液/传感器界面去除不需要的气泡。在空气中以及浸入盐溶液、乙二醇或牛血中时，测量未涂层（裸）传感器和ZnO改性传感器的共振幅度。与裸的疏水传感器相比，我们发现浸入液体的ZnO纳米棒改性传感器共振幅度的标准偏差大幅降低，从牛血的27%降低到盐溶液的67%。使用超亲水涂层的策略可应用于具有类似界面问题的其他系统。
