School of Chemistry, F11, The University of Sydney, NSW 2006, Australia.
Langmuir. 2011 Jun 7;27(11):6712-9. doi: 10.1021/la104597d. Epub 2011 May 4.
Here we report a new study on the boundary conditions for the flow of a simple liquid in a confined geometry obtained by measuring hydrodynamic drainage forces with colloid probe atomic force microscopy (AFM). In this work, we provide experimental data obtained using a best practice experimental protocol and fitted with a new theoretical calculation (Zhu, L.; Attard, P.; Neto, C. Langmuir 2010, submitted for publication, preceding paper). We investigated the hydrodynamic forces acting on a silica colloid probe approaching a hydrophobized silicon surface in a single-component viscous Newtonian liquid (di-n-octylphthalate), a partially wetting system. The measured average slip lengths were in the range of 24-31 nm at approach velocities of between 10 and 80 μm/s. Using our experimental approach, the presence of nanoparticle contaminants in the system can be indentified, which is important because it has been shown that nanoparticles lead to a large apparent slip length. Under our stringent control of experimental conditions, the measurement of the slip length is reproducible and independent of the spring constant of the cantilever.
我们通过胶体探针原子力显微镜（AFM）测量流体动力学排水力，报告了一种新的受限几何形状中简单液体流动的边界条件的研究。在这项工作中，我们提供了使用最佳实践实验方案获得的实验数据，并使用新的理论计算进行了拟合（Zhu，L.；Attard，P.；Neto，C. Langmuir 2010，即将发表的论文）。我们研究了在单组分粘性牛顿液体（邻苯二甲酸二辛酯）中，接近疏水硅表面的二氧化硅胶体探针所受的流体动力的作用，这是一个部分润湿系统。在 10 到 80 μm/s 的接近速度下，测量的平均滑移长度在 24-31nm 范围内。使用我们的实验方法，可以识别系统中纳米颗粒污染物的存在，这很重要，因为已经表明纳米颗粒会导致明显的滑移长度增加。在我们对实验条件的严格控制下，滑移长度的测量是可重复的，并且与悬臂梁的弹性常数无关。
