The Influence of Intrinsic Water and Ion Permeation on the Dielectric Properties of Parylene C Films

Published

July 3, 2023

Author(s)

Jacob Pawlik, Nick Barrera, Ellis Meng, Jim Booth, Chris Long, Nate Orloff, Eugene Yoon, Angela Stelson

Abstract

Parylene C is a widely used dielectric barrier in implantable medical devices because it conforms well to surfaces and insulates against biological environments. However, multiple studies have shown that moisture can intrude into Parylene C films through defects and intrinsic diffusion, leading to delamination and device failure. While many studies have tested device integrity in vitro, few have isolated the influence of specific degradation mechanisms on device failure. Here, we use a broadband impedance technique called Microwave Microfluidic Spectroscopy (MMS) to measure fluid permeation in targeted regions of Parylene C films that are free of defects and have optimal adhesion to the substrate. We found no changes in the broadband S-parameters from 100 MHz - 110 GHz for Parylene C coated coplanar waveguides soaked in water or phosphate buffered saline at 20°C or 37°C for two months. Furthermore, there was no loss of structural integrity induced by fluid soaking. Our study helps to clear debate about the influence of water and ion diffusion on Parylene C device lifetime and inform better fabrication of Parylene C coatings for implantable devices.

Citation

IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology

Volume

7

Issue

4

Pub Type

Journals

Download Paper

https://doi.org/10.1109/JERM.2023.3285049

Local Download

Keywords

Parylene C, Microwave Microfluidic Spectroscopy (MMS), dielectric spectroscopy, S-parameters, lab-on-a-chip, biomedical devices, implantable devices

Citation

Pawlik, J. , Barrera, N. , Meng, E. , Booth, J. , Long, C. , Orloff, N. , Yoon, E. and Stelson, A. (2023), The Influence of Intrinsic Water and Ion Permeation on the Dielectric Properties of Parylene C Films, IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology, [online], https://doi.org/10.1109/JERM.2023.3285049, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935729 (Accessed October 17, 2025)