Interfacial adsorbate organization influences a variety
physicochemical
properties and reactivity. Surfaces that are rough, defect laden,
or have large fluctuations (as in soft matter interfaces) can lead
to complex adsorbate structures. This is amplified if adsorbate–adsorbate
interactions lead to self-assembly. Although image analysis algorithms
are somewhat common for the study of solid interfaces (from microscopy
for example), images are often not readily available for adsorbates
at soft matter surfaces, and the complexity of adsorbate organization
necessitates the development of new characterization approaches. Here
we propose the use of adsorbate “density” images from
molecular dynamics simulations of liquid/vapor and liquid/liquid interfaces.
Topological data analysis is employed to characterize surface active
amphiphile self-assembly under nonreactive and reactive conditions.
We develop a chemical interpretation of sublevelset persistent homology
barcode representations of the density images, in addition to descriptors
that clearly differentiate between different reactive and nonreactive
organizational regimes. The complexity of amphiphile self-assembly
at highly dynamic liquid/liquid interfaces represents a worst-case
scenario for adsorbate characterization, and as such the methodology
developed is completely generalizable to a wide variety of surface
image data, whether from experiment or computer simulation.