Atomic Force Microscopy of Polymer Droplets

Abstract

The near-surface structure of polymers is important for understanding such macroscopic properties as adhesion, friction, and fracture initiation. Studies of polymers near surfaces by conventional transmission electron microscopy (CTEM), selected area electron diffraction (SAED), and high resolution electron microscopy (HREM) have provided local information about the reorganization of macromolecules near constraining surfaces. Atomic Force Microscopy (AFM) is now emerging as a powerful technique for characterizing local surface structure but AFM is only reliable when used in conjunction with these other more traditional microscopic techniques. It is important to establish that features observed in AFM can be corroborated by other experiments. It is also necessary to compare experimental data with theoretical descriptions which take account of the geometry of the probe-sample interaction. Computer simulations indicate that artifacts can be observed in the images including high frequency “ringing” and “beating.”

Our work has focused on the characterization of the poly(mide) PMDA-ODA in thin films and solution rown single crystals. We have also investigated the structural evolution of genetically engineered silk-like poly(peptides) as a function of processing condition. The shape of the probe can be from images of model structures such as poly (styrene) spheres.