Dielectric constant and breakdown field studies of electrostatic self-assembled materials

Electrical properties of electrostatic self-assembled (ESA) films were investigated using a conductive polymer and metal bar. These nanostructured polymeric films were fabricated on gold-coated glass slides using the ESA method. The thicknesses of the films were in the range 120–630 nm, and the films were obtained by depositing numbers of bilayers of negatively charged Poly s-119 (PS-119) or heparin and positively charged Poly(diallyldimethylammonium chloride) (PDDA). Measurement electrodes were fabricated on the ESA films using conductive silver grease and a brass bar. Capacitance measurements were conducted to determine the dielectric constant of the ESA films over various temperature and frequency ranges at 1 mV and 15% relative humidity, while electric field breakdown tests were performed at 1000 Hz, 15% relative humidity and varying temperatures and voltages. The test results showed that dielectric constant values were between 1.8 and 2.4 and breakdown field values were approximately 9 kV mm−1. Based on the test results, it is concluded that this is a technique that might prove useful in estimating the capacitance, dielectric constant and breakdown field values of nanostructured ESA films.