Nanoscale Indentation of Polymer Systems Using the Atomic Force Microscope

Abstract The use of the atomic force microscope (AFM) to measure surface forces has been developed to optimize its operation as a surface imaging tool. This capability can potentially be extended to evaluate nanoscale material response to indentation and would be ideal for the evaluation of multi-component polymer systems, such as adhesives and composites. In this paper, previous work related to the development of the AFM as a nanoindentation device is reviewed, and a technique is proposed which allows the AFM to be used to probe local stiffness changes in polymer systems. Cantilever probes with spring constants ranging from 0.4–150 N m were used to investigate a number of polymer systems, including an elastomer, several polyurethane systems, thermally cured epoxies, a thermoplastic polymer-thermosetting polymer adhesive system, and a thermoplastic matrix composite. Key Words: Atomic force microscopeforce curvesindentationelastic moduluspolymerselastomerpolyurethaneepoxyfiber-reinforced polymer compositeinterphase regions