Liquid crystal polymer (LCP) has gained wide interest in the electronics industry largely due to its flexibility, stable insulation and dielectric properties and chip integration capabilities. Recently, LCP has also been investigated as a biocompatible substrate for the fabrication of multielectrode arrays. Realizing a fully implantable LCP-based bioelectronic device, however, still necessitates a low form factor packaging solution to protect the electronics in the body. In this work, we investigate two promising encapsulation coatings based on thin-film technology as the main packaging for LCP-based electronics. Specifically, a HfO2–based nanolaminate ceramic (TFE1) deposited via atomic layer deposition (ALD), and a hybrid Parylene C-ALD multilayer stack (TFE2), both with a silicone finish, were investigated and compared to a reference LCP coating. T-peel, water-vapour transmission rate (WVTR) and long-term electrochemical impedance spectrometry (EIS) tests were performed to evaluate adhesion, barrier properties and overall encapsulation performance of the coatings. Both TFE materials showed stable impedance characteristics while submerged in 60 °C saline, with TFE1-silicone lasting more than 16 months under a continuous 14V DC bias (experiment is ongoing). The results presented in this work show that WVTR is not the main factor in determining lifetime, but the adhesion of the coating to the substrate materials plays a key role in maintaining a stable interface and thus longer lifetimes. ... Read more

Rifting and related normal stress regime in the equatorial continental margin of Brazil ceased during the Late Cretaceous, when the stress regimes in eastern South America and West Africa changed to induce strike-slip or reverse motion. In this study, we explore the postrift tectonic, geomorphic, magmatic, and sedimentary responses to stress changes using the Potiguar Basin, the easternmost basin in the equatorial margin of Brazil, as a case study. We use field and topographic data, 2D seismic reflection lines, vertical electric soundings, and geochronological and borehole data to constrain the stress evolution of the Potiguar Basin from the Late Cretaceous to the Quaternary, discussing the role of basin inversion on sedimentation and landforms. Our results indicate the presence of two strike-slip stress regimes after rifting. The first stress field (SF1) occurred from Late Cretaceous to the middle Miocene and consisted of a N-S-oriented maximum subhorizontal compression and an E-W-oriented extension. The second stress field (SF2) took place from the middle Miocene to the present day and included subhorizontal E-W to NW-SE compression combined with N-S and NE-SW subhorizontal extension. Emplacement of volcanic rocks occurred along transtensional faults, with a principal peak during SF1 at 20–30 Ma and a subordinate peak during SF2 at 5–10 Ma. In response to shortening during SF2, a 70-km-long and 50-km-wide dome formed, where marine Miocene strata were uplifted to ~250 m asl. This uplift induced the displacement of alluvial channels away from the dome. Anticlines formed by transpression along the main NE-SW-striking faults during both SF1 and ST2 acted as traps in the petroleum system. Similar shifts and stress field inversions documented in other areas of the Brazilian continental margin are consistent with the Neogene rise of the Andes and may have implications for reconstructing the tectonic history of the Equatorial Atlantic margin of South America. ... Read more