Imaging of various surface properties of fluorescently labelled phospholipid Langmuir-Blodgett films with a combined scanning probe microscope

We present results of phase separation of a single-component system of 1,2-dihexadecanoyl-sn-glycero-3-phospho-[N-(4-nitrobenz)-2-oxa-1,3-diazolyl]ethanolamine in which a liquid-condensed (LC) phase co-exists with a liquid-expanded (LE) phase. Domain formation in the co-existence region was studied using a newly developed combined scanning near-field optical microscope-atomic force microscope (SNOM-AFM). We demonstrate for the first time that the topographic, friction, fluorescence and surface potential distributions for a phase-separated single-component Langmuir-Blodgett film between the LE and LC phases can be simultaneously observed using the SNOM-AFM with a thin-step etched optical fibre probe.