Effect of toluene extraction on Biomer surface: II. An atomic force microscopy study.

The surface characterization of Biomer and extracted Biomer has been investigated using atomic force microscopy (AFM) in order to show the influence of extraction process on the morphology and local interactions which monitor surface properties at a molecular scale. The high viscoelasticity of these polymers provided by the soft segments makes AFM imaging in contact mode quite difficult, the scanning of the tip inducing artifacts on the surface. The rate, direction, and number of scans strongly influence this friction effect. The recording of force curves has shown that the extraction and conditions of drying can modify the interaction forces present at the polymer surface. Imaging of the extracted Biomer obtained with AFM in non-contact mode has revealed inclusion nodules embedded in an amorphous phase. This may be attributed to the migration at the surface of the non-eliminated poly(aminomethacrylate) additive.