{"id":{"repo_id":"queens","oai_identifier":"oai:queensu.scholaris.ca:1974/34479"},"canonical_url":"https://search.dev.ndltd.org/etd/queens/oai:queensu.scholaris.ca:1974/34479","repository":{"repo_id":"queens","name":"Queens University","base_url":"https://qspace.library.queensu.ca/server/oai/request"},"display":{"title":"Implications of Nanofiber Length and Polydispersity on Flow Alignment","abstract":"Self-assembling protein nanofibers (PNFs) offer a sustainable alternative to traditional polymers in specialty applications. Their ability to form stable, tunable, and anisotropic structures makes them a compelling system for studying flow-induced alignment, a key factor in designing bio-based materials with tailored properties. While structural properties of PNFs are at rest well-characterized, comprehensive insight into their colloidal behavior, shear response, and alignment mechanisms remain limited. Additionally, few experimental techniques can probe nanoscale orientation under dynamic conditions, making it difficult to correlate rheological properties with shear-induced alignment. This thesis investigates how fibril length and polydispersity influence the bulk rheology and nanoscale alignment of PNFs under shear using rheology, polarized optical microscopy (POM), and a novel approach to measure 3D orientation distributions in flowing suspensions with small-angle neutron scattering (SANS). Hen egg-white lysozyme (HEWL) PNFs with controlled aspect ratios and polydispersities were prepared by sonication and dialysis, allowing for systematic evaluation of flow behavior. Dynamic light scattering (DLS) and atomic force microscopy (AFM) confirmed that sonicated fibrils were shorter and more colloidally stable, while dialyzed fibrils had lower surface charge. Steady shear rheology of 2 wt% PNFs showed that short fibrils exhibited constant viscosity, while longer fibrils demonstrated shear-thinning as viscosity decreased with increasing shear rate due to alignment. At higher concentrations (3 and 5wt%), longer fibrils exhibited stronger shear-thinning due to increased interactions. At lower concentrations (0.5 and 1wt%), viscosity and shear response were weaker, indicating fewer fibril-fibril interactions. POM confirmed alignment through birefringence patterns. To quantify nanoscale alignment during flow, a wormlike micelle (WLM) solution was studied using SANS to establish a methodology for future PNF studies. This thesis introduces Rheo-SANS slices, an adaptation combining sector slicing and intensity peak analysis to assess alignment variation across beam positions and shear rates. The agreement between multiple alignment metrics validated the Rheo-SANS methodology, demonstrating its effectiveness in characterizing shear-induced ordering in anisotropic suspensions. This work establishes a quantitative framework for characterizing shear alignment, supporting future research on PNFs and related anisotropic biopolymer systems. The ability to control and characterize alignment has implications for biomaterial design, bioinspired processing, and soft matter physics.","abstract_html":"Self-assembling protein nanofibers (PNFs) offer a sustainable alternative to traditional polymers in specialty applications. Their ability to form stable, tunable, and anisotropic structures makes them a compelling system for studying flow-induced alignment, a key factor in designing bio-based materials with tailored properties. While structural properties of PNFs are at rest well-characterized, comprehensive insight into their colloidal behavior, shear response, and alignment mechanisms remain limited. Additionally, few experimental techniques can probe nanoscale orientation under dynamic conditions, making it difficult to correlate rheological properties with shear-induced alignment. This thesis investigates how fibril length and polydispersity influence the bulk rheology and nanoscale alignment of PNFs under shear using rheology, polarized optical microscopy (POM), and a novel approach to measure 3D orientation distributions in flowing suspensions with small-angle neutron scattering (SANS). Hen egg-white lysozyme (HEWL) PNFs with controlled aspect ratios and polydispersities were prepared by sonication and dialysis, allowing for systematic evaluation of flow behavior. Dynamic light scattering (DLS) and atomic force microscopy (AFM) confirmed that sonicated fibrils were shorter and more colloidally stable, while dialyzed fibrils had lower surface charge. Steady shear rheology of 2 wt% PNFs showed that short fibrils exhibited constant viscosity, while longer fibrils demonstrated shear-thinning as viscosity decreased with increasing shear rate due to alignment. At higher concentrations (3 and 5wt%), longer fibrils exhibited stronger shear-thinning due to increased interactions. At lower concentrations (0.5 and 1wt%), viscosity and shear response were weaker, indicating fewer fibril-fibril interactions. POM confirmed alignment through birefringence patterns. To quantify nanoscale alignment during flow, a wormlike micelle (WLM) solution was studied using SANS to establish a methodology for future PNF studies. This thesis introduces Rheo-SANS slices, an adaptation combining sector slicing and intensity peak analysis to assess alignment variation across beam positions and shear rates. The agreement between multiple alignment metrics validated the Rheo-SANS methodology, demonstrating its effectiveness in characterizing shear-induced ordering in anisotropic suspensions. This work establishes a quantitative framework for characterizing shear alignment, supporting future research on PNFs and related anisotropic biopolymer systems. The ability to control and characterize alignment has implications for biomaterial design, bioinspired processing, and soft matter physics.","abstract_has_math":false,"creators":["Naime, Marwa"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Chemical Engineering","school":null,"contributors":[],"advisors":["Kontopoulou, Marianna","De France, Kevin","Gilbert, Peter"],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-04-24","date_published":"2025-04-24","updated_at":"2026-07-27T20:35:37Z","subjects":["Protein Nanofiber (PNFs)","Lysozyme","Amyloid Fibrils","Flow-induced Alignment","Shear Rheology","rheoSANS","Small Angle Neutron Scattering (SANS)","Polarized Optical Microscopy (POM)","Anisotropic Suspensions"],"languages":["eng"],"rights":["Attribution-NoDerivatives 4.0 International"],"rights_urls":["http://creativecommons.org/licenses/by-nd/4.0/"],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1974/34479","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Chemical Engineering"]},{"key":"dc:contributor.supervisor","label":"Supervisor","values":["Kontopoulou, Marianna","De France, Kevin","Gilbert, Peter"]},{"key":"dc:creator","label":"Author","values":["Naime, Marwa"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-04-24T15:07:07Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-04-24T15:07:07Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-04-24"]},{"key":"dc:type","label":"Dc Type","values":["thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Protein Nanofiber (PNFs)","Lysozyme","Amyloid Fibrils","Flow-induced Alignment","Shear Rheology","rheoSANS","Small Angle Neutron Scattering (SANS)","Polarized Optical Microscopy (POM)","Anisotropic Suspensions"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Attribution-NoDerivatives 4.0 International"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://creativecommons.org/licenses/by-nd/4.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1974/34479"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Self-assembling protein nanofibers (PNFs) offer a sustainable alternative to traditional polymers in specialty applications. Their ability to form stable, tunable, and anisotropic structures makes them a compelling system for studying flow-induced alignment, a key factor in designing bio-based materials with tailored properties. While structural properties of PNFs are at rest well-characterized, comprehensive insight into their colloidal behavior, shear response, and alignment mechanisms remain limited. Additionally, few experimental techniques can probe nanoscale orientation under dynamic conditions, making it difficult to correlate rheological properties with shear-induced alignment. This thesis investigates how fibril length and polydispersity influence the bulk rheology and nanoscale alignment of PNFs under shear using rheology, polarized optical microscopy (POM), and a novel approach to measure 3D orientation distributions in flowing suspensions with small-angle neutron scattering (SANS). Hen egg-white lysozyme (HEWL) PNFs with controlled aspect ratios and polydispersities were prepared by sonication and dialysis, allowing for systematic evaluation of flow behavior. Dynamic light scattering (DLS) and atomic force microscopy (AFM) confirmed that sonicated fibrils were shorter and more colloidally stable, while dialyzed fibrils had lower surface charge. Steady shear rheology of 2 wt% PNFs showed that short fibrils exhibited constant viscosity, while longer fibrils demonstrated shear-thinning as viscosity decreased with increasing shear rate due to alignment. At higher concentrations (3 and 5wt%), longer fibrils exhibited stronger shear-thinning due to increased interactions. At lower concentrations (0.5 and 1wt%), viscosity and shear response were weaker, indicating fewer fibril-fibril interactions. POM confirmed alignment through birefringence patterns. To quantify nanoscale alignment during flow, a wormlike micelle (WLM) solution was studied using SANS to establish a methodology for future PNF studies. This thesis introduces Rheo-SANS slices, an adaptation combining sector slicing and intensity peak analysis to assess alignment variation across beam positions and shear rates. The agreement between multiple alignment metrics validated the Rheo-SANS methodology, demonstrating its effectiveness in characterizing shear-induced ordering in anisotropic suspensions. This work establishes a quantitative framework for characterizing shear alignment, supporting future research on PNFs and related anisotropic biopolymer systems. The ability to control and characterize alignment has implications for biomaterial design, bioinspired processing, and soft matter physics."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["M.Sc."]},{"key":"dc:title","label":"Title","values":["Implications of Nanofiber Length and Polydispersity on Flow Alignment"]}]}],"canonical_facts":{"dc:contributor.department":["Chemical Engineering"],"dc:contributor.supervisor":["Kontopoulou, Marianna","De France, Kevin","Gilbert, Peter"],"dc:creator":["Naime, Marwa"],"dc:date.accessioned":["2025-04-24T15:07:07Z"],"dc:date.available":["2025-04-24T15:07:07Z"],"dc:date.issued":["2025-04-24"],"dc:description.abstract":["Self-assembling protein nanofibers (PNFs) offer a sustainable alternative to traditional polymers in specialty applications. Their ability to form stable, tunable, and anisotropic structures makes them a compelling system for studying flow-induced alignment, a key factor in designing bio-based materials with tailored properties. While structural properties of PNFs are at rest well-characterized, comprehensive insight into their colloidal behavior, shear response, and alignment mechanisms remain limited. Additionally, few experimental techniques can probe nanoscale orientation under dynamic conditions, making it difficult to correlate rheological properties with shear-induced alignment. This thesis investigates how fibril length and polydispersity influence the bulk rheology and nanoscale alignment of PNFs under shear using rheology, polarized optical microscopy (POM), and a novel approach to measure 3D orientation distributions in flowing suspensions with small-angle neutron scattering (SANS). Hen egg-white lysozyme (HEWL) PNFs with controlled aspect ratios and polydispersities were prepared by sonication and dialysis, allowing for systematic evaluation of flow behavior. Dynamic light scattering (DLS) and atomic force microscopy (AFM) confirmed that sonicated fibrils were shorter and more colloidally stable, while dialyzed fibrils had lower surface charge. Steady shear rheology of 2 wt% PNFs showed that short fibrils exhibited constant viscosity, while longer fibrils demonstrated shear-thinning as viscosity decreased with increasing shear rate due to alignment. At higher concentrations (3 and 5wt%), longer fibrils exhibited stronger shear-thinning due to increased interactions. At lower concentrations (0.5 and 1wt%), viscosity and shear response were weaker, indicating fewer fibril-fibril interactions. POM confirmed alignment through birefringence patterns. To quantify nanoscale alignment during flow, a wormlike micelle (WLM) solution was studied using SANS to establish a methodology for future PNF studies. This thesis introduces Rheo-SANS slices, an adaptation combining sector slicing and intensity peak analysis to assess alignment variation across beam positions and shear rates. The agreement between multiple alignment metrics validated the Rheo-SANS methodology, demonstrating its effectiveness in characterizing shear-induced ordering in anisotropic suspensions. This work establishes a quantitative framework for characterizing shear alignment, supporting future research on PNFs and related anisotropic biopolymer systems. The ability to control and characterize alignment has implications for biomaterial design, bioinspired processing, and soft matter physics."],"dc:description.degree":["M.Sc."],"dc:identifier.uri":["https://hdl.handle.net/1974/34479"],"dc:language.iso":["eng"],"dc:rights":["Attribution-NoDerivatives 4.0 International"],"dc:rights.uri":["http://creativecommons.org/licenses/by-nd/4.0/"],"dc:subject":["Protein Nanofiber (PNFs)","Lysozyme","Amyloid Fibrils","Flow-induced Alignment","Shear Rheology","rheoSANS","Small Angle Neutron Scattering (SANS)","Polarized Optical Microscopy (POM)","Anisotropic Suspensions"],"dc:title":["Implications of Nanofiber Length and Polydispersity on Flow Alignment"],"dc:type":["thesis"]},"updated_at":"2026-07-27T20:35:37Z"}