Apparatus for the Continuous Monitoring of Surface Morphology via Fluorescence Microscopy during Monolayer Transfer to Substrates

Langmuir monolayers can be characterized at the air−subphase interface with fluorescence microscopy at the micron scale, but must be transferred to solid substrates for higher resolution imaging using atomic force microscopy. To utilize both techniques to characterize the same region of interest or to ensure that the deposition process is artifact-free, we have developed a transfer technique that allows for the continuous optical imaging of surface morphology as the monolayer is transferred from the air−subphase interface to the substrate. The advantages of this deposition technique are that it is simple and inexpensive and can be implemented in almost all Langmuir troughs and that artifacts associated with nonideal transfer can readily be identified. This new transfer technique is ideal for transferring rigid and viscous films that are difficult to deposit using the traditional Langmuir−Blodgett technique. This technique can also be used for transferring monolayers to germanium attenuated total reflection (ATR) crystals for Fourier transform infrared (FTIR)−ATR spectroscopic measurements of protein conformation and lipid orientation while maintaining the desired monolayer morphologies.