Zhang Fanfan, Gui Xiahui, Xing Yaowen, Cao Yijun, Che Tao
School of Chemical Engineering and Technology, China University of Mining and Technology, No. 1 Daxue Road, Tongshan District, Xuzhou, Jiangsu 221116, China.
Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, No. 1 Daxue Road, Tongshan District, Xuzhou, Jiangsu 221116, China.
ACS Omega. 2020 Aug 4;5(32):20363-20372. doi: 10.1021/acsomega.0c02327. eCollection 2020 Aug 18.
In this study, hydrophilic, medium hydrophobic, and strong hydrophobic probes are obtained via treatment with plasma and octadecyl trichlorosilane. The interaction between the probes and interfacial nanobubbles (INBs) is examined using atomic force microscopy. The results show that a hydrophilic probe can scan the true shape of the INBs, and the distance between the first inflection point and the zero point of the approach force curve is equal to the vertical height of the nanobubble. The medium hydrophobic probe caused severe deformation of INB morphologies in the horizontal direction during scanning; nevertheless, the complete shape of the INB is obtained using this probe by lowering the scanning parameters. However, the characteristic of the approach force curve proves that the size of the nanobubbles is underestimated. The strong hydrophobic probe deforms INB morphologies severely, whose size cannot be obtained. The maximum attractive force in the approach force curve and the adhesive force in the retract force curve obtained using the strong hydrophobic probe are approximately 6 and 12 nN, respectively, which are both higher than those of the hydrophilic and medium hydrophobic probes. It is reasoned that the liquid film is maintained between the hydrophilic probe and the INBs, the medium hydrophobic probe pierces the INBs slightly, while the strong hydrophobic probe punctures the liquid film and demonstrates a pinning effect.
在本研究中，通过等离子体处理和十八烷基三氯硅烷获得亲水性、中等疏水性和强疏水性探针。使用原子力显微镜研究探针与界面纳米气泡（INB）之间的相互作用。结果表明，亲水性探针可以扫描INB的真实形状，接近力曲线的第一个拐点与零点之间的距离等于纳米气泡的垂直高度。中等疏水性探针在扫描过程中导致INB形态在水平方向上严重变形；然而，通过降低扫描参数，使用该探针可获得INB的完整形状。然而，接近力曲线的特征证明纳米气泡的尺寸被低估了。强疏水性探针使INB形态严重变形，无法获得其尺寸。使用强疏水性探针获得的接近力曲线中的最大吸引力和回缩力曲线中的粘附力分别约为6和12 nN，均高于亲水性和中等疏水性探针。据推测，亲水性探针与INB之间保持着液膜，中等疏水性探针轻微刺穿INB，而强疏水性探针刺穿液膜并表现出钉扎效应。
