Test methodMeasurement of the elastic modulus of polymeric films using an AFM with a steel micro-spherical probe tip

The elastic moduli of polystyrene (PS), polymethylmethacrylate (PMMA) and polydimethylsiloxane (PDMS) films were evaluated using an Atomic Force Microscope (AFM) with a steel micro-spherical probe tip. The elastic moduli of the polymeric films were determined with respect to indentation depth using the Hertz and Johnson-Kendall-Roberts (JKR) models. The measured elastic moduli of PS, PMMA and PDMS were determined to be 2.6 GPa, 0.74 GPa, and 4 MPa at indentation depths of 1.7 nm, 4 nm, and 120 nm, respectively. These results confirm the validity of the proposed method for effectively measuring the elastic properties of polymeric thin films.