Imaging and manipulation of nanometer-size liquid droplets by scanning polarization force microscopy

Abstract

Follow this and additional works at: http://repository.upenn.edu/meam_papers Copyright (1996) Recommended CitationHu, Jun; Carpick, Robert W.; Salmeron, Miquel; and Xiao, Xu-dong, "Imaging and manipulation of nanometer-size liquid droplets by scanning polarization force microscopy" (1996). Departmental Papers (MEAM). 98. http://repository.upenn.edu/meam_papers/98Imaging and manipulation of nanometer-size liquid droplets by scanning polarization force microscopy AbstractUsing atomic force microscopy in noncontact mode, we have imaged nanometer-size liquid droplets of KOH water solutions on the surfaces of highly oriented pyrolitic graphite and mica. On graphite the droplets prefer to be adsorbed on atomic step edges. Droplets on the same step tend to be evenly spaced and of similar size. The droplets can be manipulated by the atomic force microscopy tip allowing the controllable formation of droplet patterns on the surface. Using atomic force microscopy in noncontact mode, we have imaged nanometer-size liquid droplets of KOH water solutions on the surfaces of highly oriented pyrolitic graphite and mica. On graphite the droplets prefer to be adsorbed on atomic step edges. Droplets on the same step tend to be evenly spaced and of similar size. The droplets can be manipulated by the atomic force microscopy tip allowing the controllable formation of droplet patterns on the surface.

Molecular-scale Hydrophilicity Induced by Solute: Molecular-thick Charged Pancakes of Aqueous Salt Solution on Hydrophobic Carbon-based Surfaces

“…The HOPG fragment was fixed to the sample holder using electric conductive adhesive with the working side up, and was freshly cleaved using double-faced adhesive tape. The NaCl sample was prepared according to a process previously reported for the observation of liquid nanodroplets of KOH by scanning polarization force microscopy 54 on graphite. Briefly, a drop (~20 μl) of NaCl solution (20 mM) was deposited on the HOPG substrate, and the droplet was then dried with a stream of air at room temperature and 40%–60% relative humidity.…”

Study of Liquid Crystal Prewetting Films by Atomic Force Microscopy in Tapping Mode

“…In this paper, we show that it is possible to use tapping mode scanning force microscopy for nondestructive imaging of liquid crystal prewetting films which are molecularly thin. Some notable success has already been documented, where atomic force microscopy has been used to study liquids − and liquid crystals. − Here, we focus on the physical relevance of the images obtained on very thin liquid films, we study systematically some artifacts, and we address the problem of height measurement. We think that, beyond the study of liquid crystal organization, the results presented in this paper can be useful to determine a general methodology for the study of molecularly thin liquids films by tapping mode atomic force microscopy (TMAFM).…”

Imaging Liquid Structures on Inhomogeneous Surfaces by Scanning Force Microscopy

“…However, one might anticipate that the interaction of the scanning tip with the liquid to be imaged will distort, or even destroy, the liquid structure of interest. In fact, there has been quite a lot of work toward noncontact imaging techniques for liquids, trading off a serious reduction in resolution.…”

“…The hydrophobic coating consisted of a covalently bound layer of (heptadecafluoro-1,1,2,2,-tetrahydrodecyl)dimethylchlorosilane (C 12 H 10 F 17 SiCl) deposited from hexane solution by means of a silicone rubber stamp. − The droplets were created by means of an atomizer (Fleischhacker, Germany) and were deposited on the substrate out of the aerosol phase. For the small droplets of interest here, this method minimizes contact line pinning effects, as opposed to other methods …”