  The presence of nanobubbles on lubricant-infused surfaces (LIS) has so far
been overlooked due to the difficulty in detecting them in such a complex
system. We recently showed that anomalously large interfacial slip measured on
LIS is explained by the presence of nanobubbles. Crucial to drawing this
conclusion was the use of atomic force microscopy (AFM) force-distance
spectroscopy to directly image nanobubbles on LIS. This technique provided
vital direct evidence of the spontaneous nucleation of nanobubbles on
lubricant-infused hydrophobic surfaces. In this paper, we describe in detail
the data collection and analysis of AFM meniscus force measurements on LIS and
show how these powerful measurements can quantify both the thickness and
distribution of multiple coexisting fluid layers (i.e. gas and oil) over a
nanostructured surface.
