牛津仪器视频级原子力显微镜应用于表面活性剂胶束动力学成像的新进展

表面活性剂具有许多重要的工业应用，包括胶体分散体（例如，洗涤剂）的稳定化、腐蚀抑制和润滑。它们在表面上形成有序的胶体结构或胶束，使它们作为模板来构建纳米结构，这也就不难理解其在固液界面上至关重要的影响。高速视频级原子力显微镜（AFM）的应用，使得对表面活性剂胶束的研究在高分辨率和高速度实现巨大的突破。牛津仪器Asylum Research发布的 “高速视频级原子力显微镜为固液界面表面活性剂最新研究方向”的应用报告呈现了这些研究成果。其介绍了采用Asylum Research Cypher VRS高速视频级原子力显微镜研究CTAB（一种常见表面活性剂材料）胶束、方法及视频结果。

图注：从每秒5.8帧（每帧173毫秒）捕获的视频中提取的单个帧，在HOPG表面上显示出清晰的CTAB形成的半胶束和胶束边界的取向。展示的结果为相位（Phase Image）数据。

牛津仪器Asylum Research市场总监Ben Ohler评价道：“Asylum Research Cypher VRS 原子力显微镜拥有视频级超高速成像速度，可以非常容易地实现固液界面表面活性剂胶束动力学的可视化和定量化的研究。我们希望这一应用报告可以激励研究人员更多采用视频级别的原子力显微镜进行自组装领域的研究或任何纳米尺度的动力学研究，包括生化反应、自组装过程或相结构和晶粒结构的非平衡演变。”

观看完整视频

Figure 1 The full movie was collected over a period of about 11 minutes at a rate of 5.8 frames per second. The movie is being played back here at 4X the acquisition rate (i.e. 23.2 fps). The video clearly shows the rows of CTAB hemimicelles on the HOPG surface and the orientation of the domain boundaries. Tapping mode phase data is shown here for optimum contrast.

Figure 2 The full movie was collected over a period of about 12 minutes at a rate of 0.48 frames per second. The movie is being played back here at 4X the acquisition rate (i.e. 1.92 fps). Note the two CTAB grains of opposite row orientation (upper-left and lower-right) bounded on the left and right by two grains with parallel orientation. Over time, the two grains narrow at their boundary, eventually separating and drifting apart while the adjacent grains on the left and right merge together. Note the three different row orientations, corresponding to the three directions perpendicular to the HOPG symmetry axes.

Figure 3 The full movie was collected over a period of about 6 minutes at a rate of 0.95 frames per second. The movie is being played back here at 4X the acquisition rate (i.e. 3.8 fps). The video shows small features that seem to absorb into surrounding grains. The process appears analogous to Ostwald ripening, except in this two-dimensional system instead of a bulk dispersion. In both cases, the feature appears with higher phase contrast and appears less structured than the surrounding hemimicelles.