Microwave Characterization of Parylene C Dielectric and Barrier Properties

Published

June 29, 2023

Author(s)

Nikolas Dale Barrera, Jacob Pawlik, Eugene Yoon, James Booth, Christian Long, Nathan Orloff, Ellis Meng, Angela Stelson

Abstract

Parylene C thin films are commonly used as a passivation layer, protective coating, or substrate material in implantable medical devices. However, fluid or vapor may permeate through Parylene C films over time through defects, film edges, or bulk diffusion and lead to device failure in vivo. Such failure can be difficult to detect using electrochemical impedance spectroscopy (0.1 Hz – 1 MHz) which does not capture the dielectric contributions of fluid at higher frequencies. We present a method for tracking broadband (1 MHz – 110 GHz) microwave dielectric properties of polymer-fluid interfaces. Using 2D electromagnetic modeling, we simulated measurement sensitivity to potential changes in Parylene C film dielectric properties and experimentally demonstrated sensitivity to changes in film relative permittivity as small as ±0.1 and fluid layers under films as small as 5 nm. We measured films exposed to water and ionic fluid and compared measurement results to simulation results. These results enable the development of robust, hermetic polymer films in implantable medical devices and other RF applications in the analysis of complex fluids.

Proceedings Title

2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers)

Conference Dates

June 25-29, 2023

Conference Location

Kyoto, JP

Pub Type

Conferences

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Keywords

microwave, microfluidics, permittivity, Parylene C, polymer, dielectric properties, ionic conductivity, sensitivity, parametric simulation, barrier properties, S-parameters, aging, longevity, implant

Citation

Barrera, N. , Pawlik, J. , Yoon, E. , Booth, J. , Long, C. , Orloff, N. , Meng, E. and Stelson, A. (2023), Microwave Characterization of Parylene C Dielectric and Barrier Properties, 2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers), Kyoto, JP, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936402 (Accessed October 17, 2025)