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dc.rights.licenseRestricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.
dc.contributorRamanath, G. (Ganpati)
dc.contributorHull, Robert, 1959-
dc.contributorGall, Daniel
dc.contributorUllal, Chaitanya
dc.contributorLewis, Kim M.
dc.contributor.authorKwan, Matthew P.
dc.date.accessioned2021-11-03T08:53:49Z
dc.date.available2021-11-03T08:53:49Z
dc.date.created2017-11-10T12:49:55Z
dc.date.issued2017-08
dc.identifier.urihttps://hdl.handle.net/20.500.13015/2063
dc.descriptionAugust 2017
dc.descriptionSchool of Engineering
dc.description.abstractThis work demonstrates that inserting nanomolecular layers (NMLs) can profoundly change and/or lead to novel electronic and mechanical properties of metal-ceramic interfaces. The first set of results demonstrate that organophosphonate NMLs up to 1.8 nm thick can alter metal work functions by ± 0.6 eV. This work function change is a strong function of the NML terminal groups (methyl, mercaptan, carboxylic acid, or phosphonic acid), morphology (up right, lying down, or mixed orientation), and the nature of the bonding (covalent, polar, or Van der Waals) between NML and the adjacent layers. Additionally, while NML-ceramic bond type and strength can influence and counteract the effect of NML morphology, the metal-NML bond appears to be independent of the morphology of the NML underlayer. The second set of results demonstrate that inserting an organosilane NML at a metal-ceramic interface can lead to multifold fracture toughening under both static (stress corrosion) and cyclic loads (fatigue) tested in four-point bend. Nanolayer-induced interface strengthening during static loading activates metal plasticity above the metal yield strength, leading to two-fold fracture toughening. Metal plasticity-induced toughening increases as temperature is increased up to 85 °C due to decreasing yield stress. In the fatigue fracture tests I report for the first time a loading-frequency-dependent tripling in fracture toughening in the 75-300 Hz range upon inserting a mercapto-silane NML at the weakest interface of a ceramic-polymer-metal-ceramic stack. This unusual behavior arises from the NML strengthened interface enabling load transfer to- and plasticity in the polymer layer, while the fatigue toughening magnitude and frequency range are determined by polymer rheology.
dc.language.isoENG
dc.publisherRensselaer Polytechnic Institute, Troy, NY
dc.relation.ispartofRensselaer Theses and Dissertations Online Collection
dc.subjectMaterials engineering
dc.titleManipulating electronic and mechanical properties at metal-ceramic interfaces with a nanomolecular layer
dc.typeElectronic thesis
dc.typeThesis
dc.digitool.pid178599
dc.digitool.pid178602
dc.digitool.pid178604
dc.rights.holderThis electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
dc.description.degreePhD
dc.relation.departmentDept. of Materials Science and Engineering


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