Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Growth Rates of Hydrogen Microbubbles in Reacting Femtoliter Droplets   Chemical reactions in small droplets are extensively explored to accelerate
the discovery of new materials, increase efficiency and specificity in
catalytic biphasic conversion and in high throughput analytics. In this work,
we investigate the local rate of gas-evolution reaction within femtoliter
droplets immobilized on a solid surface. The growth rate of hydrogen
microbubbles (> 500 nm in radius) produced from the reaction was measured
online by high-resolution confocal microscopic images. The growth rate of
bubbles was faster in smaller droplets, and of bubbles near the three-phase
boundary in the same droplet. The results were consistent for both pure and
binary reacting droplets and on substrates of different wettability. Our
theoretical analysis based on diffusion, chemical reaction, and bubble growth
in a steady state predicted that the concentration of the reactant diffusing
from the surrounding depended on the droplet size and the bubble location
inside the droplet, in good agreement with experimental results. Our results
reveal that the reaction rate may be spatially non-uniform in the reacting
microdroplets. The findings may have implications for formulating chemical
properties and uses of these droplets.

22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin