--- OA_place: publisher _id: '22684' abstract: - lang: eng text: "Contact electrification (CE) is a simple yet elusive phenomenon that occurs when two materials come into contact and separate, leaving behind net electrical charge. Despite its ubiquity, the microscopic origin of CE remains unclear. In this thesis, we investigate CE from three complementary perspectives: developing a quantitative method to measure charge at the nanoscale, exploring the dynamic behavior of charge on insulating surfaces, and uncovering the role of mechanical history in forming a triboelectric series.\r\n\r\nIn the first part, we establish a rigorous framework for converting qualitative Kelvin probe force microscopy (KPFM) voltage maps into quantitative charge density distributions. Using finite element method (FEM) simulations, we determine the point-spread function of the KPFM tip–sample geometry and demonstrate that the true surface charge can be reconstructed by numerical deconvolution. This procedure enables the recovery of both the magnitude and sign of charge density with high fidelity, resolving nanoscale features that are otherwise obscured. Applying the method to contact-charged SiO$_2$ surfaces, we show that existing analytical approximations, such as parallel plate or spherical models, can miscalculate charge magnitude by orders of magnitude. Our hybrid FEM/KPFM approach therefore provides a fast and general method to convert qualitative KPFM signals into quantitative charge data, enabling nanoscale charge mapping under realistic experimental conditions.\r\n\r\nIn the second part, we study the temporal stability of CE-induced charges and identify the key material factors that determine whether KPFM can capture meaningful charge patterns. Through time-resolved experiments combining a custom-built transfer system with both microscopic and macroscopic measurements, we demonstrate that only the best insulators, such as SiO$_2$, preserve CE charge long enough for stationary imaging. For less conductive polymers, such as PDMS, charge decays within the duration of a single KPFM scan due to bulk conduction. Using a simple capacitor-based model, we reproduce the observed decay dynamics and confirm that the transferred charge decays characteristic to the sample's bulk conductivity. Further, we always observe homogeneous charge transfer.\r\n\r\nIn the third part, we address the question: can we form a triboelectric series with identical materials? Using controlled repetitive contact experiments, we show that nominally identical materials can progressively order themselves into a triboelectric series, where surfaces with more contact history charge negatively relative to fresher ones. By constructing a minimal model based on this ``contact bias'', we replicate the evolution from random to ordered charging observed in experiments. Supporting surface analyses, including atomic force microscopy, reveal that repeated contact induces nanoscale morphological changes, suggesting a mechanism tightly coupled to mechanical strain. These results highlight the crucial role of surface history and nanoscale mechanics in dictating charge transfer, motivating further exploration of mechanisms such as mechanochemical bond cleavage and flexoelectric polarization." acknowledged_ssus: - _id: NanoFab - _id: ScienComp - _id: LifeSc - _id: M-Shop - _id: EM-Fac acknowledgement: "This project has received financing from the European Research Council grant agreement\r\nno. 949120 under the European Union’s Horizon 2020 research and innovation programme.\r\nThis research was supported by the Scientific Service Units of The Institute of Science\r\nand Technology Austria (ISTA) through resources provided by the Miba Machine Shop, the\r\nNanofabrication Facility, the Lab Support Facility, the Scientific Computing Facility and the\r\nElectron Microscopy Facility. We thank Florian Stumpf from Park Systems for useful discussions\r\nand support with scanning probe microscopy. We thank Joaquin Garcia-Suarez and Guillaume\r\nAnciaux for the suggestion to look into the roughness power spectral density. We thank\r\nIrina-Malina Strugaru for help with testing the device for Young’s modulus measurements.\r\n" alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Felix full_name: Pertl, Felix id: 6313aec0-15b2-11ec-abd3-ed67d16139af last_name: Pertl orcid: 0000-0003-0463-5794 citation: ama: Pertl F. Experimental probing of nanoscale charge features and surface morphology changes during tribocharging. 2026. doi:10.15479/AT-ISTA-22684 apa: Pertl, F. (2026). Experimental probing of nanoscale charge features and surface morphology changes during tribocharging. Institute of Science and Technology Austria. https://doi.org/10.15479/AT-ISTA-22684 chicago: Pertl, Felix. “Experimental Probing of Nanoscale Charge Features and Surface Morphology Changes during Tribocharging.” Institute of Science and Technology Austria, 2026. https://doi.org/10.15479/AT-ISTA-22684. ieee: F. Pertl, “Experimental probing of nanoscale charge features and surface morphology changes during tribocharging,” Institute of Science and Technology Austria, 2026. ista: Pertl F. 2026. Experimental probing of nanoscale charge features and surface morphology changes during tribocharging. Institute of Science and Technology Austria. mla: Pertl, Felix. Experimental Probing of Nanoscale Charge Features and Surface Morphology Changes during Tribocharging. Institute of Science and Technology Austria, 2026, doi:10.15479/AT-ISTA-22684. short: F. Pertl, Experimental Probing of Nanoscale Charge Features and Surface Morphology Changes during Tribocharging, Institute of Science and Technology Austria, 2026. corr_author: '1' date_created: 2026-08-12T09:44:40Z date_published: 2026-08-12T00:00:00Z date_updated: 2026-08-27T11:42:44Z day: '12' ddc: - '530' degree_awarded: PhD department: - _id: GradSch - _id: ScWa doi: 10.15479/AT-ISTA-22684 doi_confirm: '1' ec_funded: 1 file: - access_level: closed checksum: 0a4f5a941c40b921447e72291d72bc6f content_type: application/x-zip-compressed creator: fpertl date_created: 2026-08-12T13:04:21Z date_updated: 2026-08-12T13:04:21Z file_id: '22690' file_name: 2026_Pertl_Felix_Thesis.zip file_size: 31192621 relation: source_file - access_level: open_access checksum: ae60dcdb363222138886b2857643d4e3 content_type: application/pdf creator: fpertl date_created: 2026-08-12T13:04:21Z date_updated: 2026-08-12T13:04:21Z file_id: '22691' file_name: 2026_Pertl_Felix_Thesis.pdf file_size: 27882509 relation: main_file file_date_updated: 2026-08-12T13:04:21Z has_accepted_license: '1' language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ month: '08' oa: 1 oa_version: Published Version page: '107' project: - _id: 0aa60e99-070f-11eb-9043-a6de6bdc3afa call_identifier: H2020 grant_number: '949120' name: 'Tribocharge: a multi-scale approach to an enduring problem in physics' publication_identifier: isbn: - 978-3-99078-083-1 issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '20481' relation: part_of_dissertation status: public - id: '12109' relation: part_of_dissertation status: public - id: '19278' relation: part_of_dissertation status: public - id: '17373' relation: part_of_dissertation status: public status: public supervisor: - first_name: Scott R full_name: Waitukaitis, Scott R id: 3A1FFC16-F248-11E8-B48F-1D18A9856A87 last_name: Waitukaitis orcid: 0000-0002-2299-3176 title: Experimental probing of nanoscale charge features and surface morphology changes during tribocharging tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2026' ...