![siloxane xps peak siloxane xps peak](https://pubs.rsc.org/image/article/2015/RA/c5ra12480h/c5ra12480h-f2_hi-res.gif)
Recent works have examined the effects of chemical treatment 9, 10, patterning 11, micrometer-thick adhesion layers 4, 10, crack-tip blunting 12, and cyclic loading amplitude 13 on interfacial fatigue, and described the results in terms of Paris law-based bulk-fatigue models 14, 15. Although fatigue has been widely investigated and well understood in bulk materials 7, 8, much less is known about fatigue-induced interfacial fracture, especially in coatings and thin films. Interfacial fracture can occur at significantly lower stresses than the static-loading fracture stresses 5, 6 of the materials comprising the interface, and can be exacerbated by chemical attack (stress corrosion) and cyclic loading (fatigue), thereby adversely impacting reliability and performance. Tailoring the chemistry of heterointerfaces is crucial to controlling the fracture toughness of a variety of composite materials, such as, those used in load-bearing structures 1, nanoelectronics devices 2, energy systems 3, and biomedicine 4.
Siloxane xps peak crack#
Our findings open up possibilities for realizing novel composites with inorganic-organic interfaces, e.g., arresting crack growth or stimulating controlled fracture triggered by loads with specific frequency characteristics. These results indicate the tunability of the toughening behavior through suitable choice of interfacial molecular layers and polymers. Above a threshold interfacial bond strength, the toughening magnitude and frequency range are primarily controlled by the frequency- and temperature-dependent rheological properties of the polymer. We show that this unexpected frequency-dependent toughening is underpinned by nanolayer-induced interface strengthening, which facilitates load transfer to, and plasticity in, the polymer layer. Here, we demonstrate that introducing an interfacial molecular nanolayer at the metal-ceramic interface of a layered polymer-metal-ceramic stack triples the fracture energy for ~75–300 Hz loading, yielding 40% higher values than the static-loading fracture energy. Interfacial toughening in composite materials is reasonably well understood for static loading, but little is known for cyclic loading.