Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence of Epitaxial Growth of Molecular Layers of Dissolved Gas at a
  Hydrophobic/Water Interface   The non-wetting phenomena of water on certain solid surfaces have been under
intensive study for decades, but the nature of hydrophobic/water interfaces
remains controversial. Here a water/graphite interface is investigated with
high-sensitivity atomic force microscopy. We show evidence of nucleation and
growth of an epitaxial monolayer on the graphite surface, probably caused by
adsorption of nitrogen molecules dissolved in water. The subsequent adsorption
process resembles the layer-plus-island, or Stranski-Krastanov, growth mode in
heteroepitaxy. This finding underlines the importance of gas segregation at
various water interfaces and may unravel many puzzles, especially the nature
and the high stability of so-called nanobubbles at solid/water interfaces and
in bulk water. Based on the hydrophobic effect, we propose that gas molecules
dissolved in water may aggregate into clusters in bulk water as well as at
solid/water interfaces. As a cluster grows above a critical size, it undergoes
a transition into a gas bubble, which can explain formation or nucleation of
gas bubbles in water.

23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph