BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:Virtual MEchanics GAthering -MEGA- Seminar: Extended lifetime of p artially cracked multilayer barriers for implantable electronics DTSTART:20201210T161500 DTEND:20201210T173000 DTSTAMP:20260408T071307Z UID:40581c06d97f00f31f54c367689a26d28bdb6373b5f1bc0c6e4d7455 CATEGORIES:Conferences - Seminars DESCRIPTION:Kyungjin Kim (LSBI\, EPFL)\nAbstract: Next-generation bioelect ronics develops towards flexible\, soft\, and lightweight to match dynamic s and softness in vivo. Critical challenges in deploying miniaturized and compliant implantable bioelectronic interfaces are the design\, synthesis\ , and validation of barrier coatings that combine hermeticity\, biocompati bility\, and microfabrication in agreement with physiological and therapeu tic timescales. Such barriers are conformally coated thin-films\, prepared with vacuum deposition methods\, e.g. atomic layer and chemical vapor dep osition (ALD and CVD). While the barriers prevent degradation from surroun dings (e.g.\, water vapor\, ions.)\, their interfaces and integrated devic es call for providing high reliability under mechanical deformation. In th is work\, mechanical failure under tensile strain has been thoroughly stud ied to scrutinize mechanical reliability integrity in brittle\, thin barri er films. Time-dependent cracking in flexible coatings under applied strai n was characterized using an in-situ microscopy tensile test depending on environmental conditions. Next\, nanolaminates with alternative organic an d inorganic layers were fabricated\, tested\, and modeled to produce an op timized crack onset strain. Although an ultrathin metal oxide barrier offe rs a low water permeability\, the presence of pinholes and defects hinder further improvement. Organic-inorganic multilayers were therefore investig ated to separate such defects in the inorganic layers by the organic layer s. These barrier films' chemical transport properties were assessed in par allel with their mechanical reliability and structural durability during f lexural deformation. Channel cracks formed within the organic/inorganic mu ltilayer structure were studied to calculate fracture energies to predict their failure mode. An ion-polished cross-sectional area of a multilayer f ilm which was strained to crack onset strain confirmed the proposed partia l channel crack configuration\, preserving tortuous pathways even after cr acking. Samples were characterized by a thin-film corrosion test\, leakage current monitoring of interdigitated electrodes\, and lifetime tests of c oated optoelectronic devices under accelerated aging. The lifetime of stru ctures coated with cracked multilayers displayed an extended lifetime equi valent to 3 years\, exciting results as barriers are considered no longer functioning after cracking.\n\nBio: Kyungjin is a postdoctoral fellow in t he Lacour lab for soft bioelectronic Interfaces at EPFL\, working on ultra barrier encapsulated neuroprosthetics. She received her PhD in 2018 from t he Georgia Institute of Technology\, USA\, and BS in 2014 from KAIST\, Sou th Korea\, in Mechanical Engineering. She is developing long-term function ing soft and deformable devices using vacuum processed hermetic encapsulat ions and various quality control methods. LOCATION:Zoom: epfl.zoom.us/s/98393329833 Room Passcode: 349948 http://epf l.zoom.us/s/98393329833 STATUS:CONFIRMED END:VEVENT END:VCALENDAR