Daniel Dan, Lay Chee Leng, Sng Anqi, Jun Lee Coryl Jing, Jin Neo Darren Chi, Ling Xing Yi, Tomczak Nikodem
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Innovis, Singapore 138634;
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Innovis, Singapore 138634.
Proc Natl Acad Sci U S A. 2019 Dec 10;116(50):25008-25012. doi: 10.1073/pnas.1916772116. Epub 2019 Nov 26.
There is a huge interest in developing superrepellent surfaces for antifouling and heat-transfer applications. To characterize the wetting properties of such surfaces, the most common approach is to place a millimetric-sized droplet and measure its contact angles. The adhesion and friction forces can then be inferred indirectly using Furmidge's relation. While easy to implement, contact angle measurements are semiquantitative and cannot resolve wetting variations on a surface. Here, we attach a micrometric-sized droplet to an atomic force microscope cantilever to directly measure adhesion and friction forces with nanonewton force resolutions. We spatially map the micrometer-scale wetting properties of superhydrophobic surfaces and observe the time-resolved pinning-depinning dynamics as the droplet detaches from or moves across the surface.
人们对开发用于防污和传热应用的超排斥表面有着浓厚的兴趣。为了表征此类表面的润湿性，最常见的方法是放置一个毫米大小的液滴并测量其接触角。然后可以使用弗米吉关系间接推断粘附力和摩擦力。虽然接触角测量易于实施，但它是半定量的，无法解析表面上的润湿性变化。在这里，我们将一个微米大小的液滴附着到原子力显微镜悬臂上，以直接测量具有纳牛顿力分辨率的粘附力和摩擦力。我们在空间上绘制超疏水表面的微米级润湿性，并观察液滴从表面分离或在表面移动时的时间分辨钉扎 - 解钉扎动力学。
