AFM characterization of electroactive polymer nanocomposites

An AFM-based method is used to probe the electromechanical response of a polyimide-SWNT nanocomposite at the nanoscale level. Our previous investigations on bulk polyimide-SWNT nanocomposites using a fiber optic sensor-based method have shown that the nanocomposites are electroactive and exhibit a quadratic relationship between output displacement and input voltage. In the current study, the composites are probed at the nanoscale using the AFM in contact mode. One goal of the current study is to assess the AFM-based technique in measuring our nanocomposites and verifying their actuation. A second goal is to improve the methodology itself by characterizing a commercially available piezoelectric ceramic, PZT, and a commercially available piezoelectric polymer, PVDF. The experiments are conducted in contact mode under the application of a DC voltage. Values for the strain piezoelectric coefficients d ₃₃ are widely reported in the literature and consequently permit calibration of the methodology applied in the present work. These findings, coupled with bulk film characterization will be used to shed light on the polyimide-SWNT interaction and its effect on the electroactive mechanism displayed by the nanocomposites.