Tuning lipid composition to explore the monolayer collapse phase diagram*

Langmuir monolayers provide a controlled system to study the multiscale geometry and mechanical states of lipid monolayers at an air/water interface under compression. At high lipid packing density and high surface pressure, the monolayers collapse and can be observed to undergo wrinkling, folding, crumpling, shear banding, or vesiculation. Recent work has begun to establish a general lipid monolayer collapse phase diagram, where the collapse mechanism can be altered through tuning characteristics such as lipid composition and temperature. This poster will present ongoing work in exploring uncharted regions of this phase diagram. We combine fluorescence imaging and atomic force microscopy to study the micro- and nano-scale structures to probe the mechanical properties of lipid monolayers near and during collapse at compositions of varying in-plane rigidity. We focus on the phenomenon of shear banding and the conditions necessary to produce such morphology and utilize finite element analysis to simulate collapse based on experimental data.