PDMS fluids in contact with the metal surfaces of electrical contacts can produce thin insulative polymer films due to metal catalyzed degradation and continues to be of concern for many new applications. These resulting thin PDMS films (also known as “SiCO” films) may result in an increased electrical contact resistance which ultimately impacts device performance. While PDMS is generally considered very stable and resistant to oxidative degradation at nominal temperatures, the presence of vibrational conditions and/or extensive contact sliding forces are shown to accelerate PDMS degradation processes occurring at metal surfaces (also known as frictional polymerization). While frictional polymerization of organic gases, solvents, fluids and lubricants has been known for over half a century, examples of frictional degradation in PDMS systems are rare. In this presentation we describe recent work using focal plane array (FPA) IR spectroscopy to image the thickness of the formed PDMS degradation films. It is demonstrated that the thin PDMS films observed are very heterogeneous in nature, can grow rapidly in localized defect regions, and are impacted by the specifics of the frictional/vibrational conditions along with the metal composition of the electrical contacts. These results are combined with recent density functional theory (DFT) vibrational IR spectra calculations for model siloxane chains as a function of strain and degree of cross-linking to understand and assign some of the observed IR spectral changes allowing an improved measurement of these PDMS thin films.
No datasets are available for this submission.