  The assembly of colloidal particles at liquid/liquid or air/liquid interfaces
is a versatile procedure to create microstructured monolayers and study their
behavior under compression. When combined with soft and deformable particles
such as microgels, compression is used to tune not only the interparticle
distance but also the underlying microstructure of the monolayer. So far, the
great majority of studies on microgel-laden interfaces is conducted ex situ
after transfer to solid substrates, for example, via Langmuir-Blodgett
deposition. This type of analysis relies on the stringent assumption that the
microstructure is conserved during transfer and subsequent drying. In this
work, we couple a Langmuir trough to a custom-built small-angle light
scattering setup to monitor colloidal monolayers in situ during compression. By
comparing the results with ex situ and in situ microscopy measurements, we
conclude that Langmuir-Blodgett deposition can alter the structural properties
of the colloidal monolayers significantly.
