Cho Jeong-Min, Sigmund Wolfgang M
J Colloid Interface Sci. 2002 Jan 15;245(2):405-7. doi: 10.1006/jcis.2001.8075.
The direct force measurement between colloidal surfaces has been an essential topic in both theories and applications of surface chemistry. As particle size is decreased from micron size down to true nano size (<10 nm), surface forces are increasingly important. Nanoparticles at close proximity or high solids loading are expected to show a different behavior than what can be estimated from continuum and mean field theories. The current tools for directly measuring interaction forces such as a surface force apparatus or atomic force microscopy (AFM) are limited to particles much larger than nanosize. Here a modified colloidal probe technique is suggested using a multiwalled carbon nanotube (MWNT) to overcome this problem. Determination of zero separation in AFM is critical to extract a reliable force-separation curve when MWNT is used as a probe. Hence, a systematic approach to the data collection for a nanosize colloidal probe is proposed and a sample of a direct surface force measurement curve obtained with the MWNT probe is presented.
胶体表面之间的直接力测量一直是表面化学理论和应用中的一个重要课题。随着粒径从微米级减小到真正的纳米级（<10 nm），表面力变得越来越重要。预计近距离或高固体负载下的纳米颗粒会表现出与连续介质和平均场理论估计不同的行为。目前用于直接测量相互作用力的工具，如表面力仪或原子力显微镜（AFM），仅限于比纳米尺寸大得多的颗粒。在此，提出了一种使用多壁碳纳米管（MWNT）的改进胶体探针技术来克服这一问题。当使用MWNT作为探针时，AFM中零间距的测定对于提取可靠的力-间距曲线至关重要。因此，提出了一种针对纳米尺寸胶体探针的数据收集系统方法，并展示了用MWNT探针获得的直接表面力测量曲线样本。
