{"id":{"repo_id":"cambridge","oai_identifier":"oai:www.repository.cam.ac.uk:1810/389876"},"canonical_url":"https://search.dev.ndltd.org/etd/cambridge/oai:www.repository.cam.ac.uk:1810/389876","repository":{"repo_id":"cambridge","name":"Cambridge University","base_url":"https://api.repository.cam.ac.uk/server/oai/request"},"display":{"title":"Surface Functionalisation and Characterisation of Cellulose Nanocrystals","abstract":"Cellulose nanocrystals (CNCs) are elongated nanoscale crystalline particles able to be extracted from cellulose. They are noted for their combination of strength, stiffness, low density, and biodegradability, as well as emergent properties, such as forming birefringent liquid crystals. CNCs have found applications as a promising new nanomaterial, used in polymer composites, biocompatible scaffolds and optical materials. All these applications depend on the surface properties of CNCs, therefore reliable quantitative characterisation methods of these properties are required. The chemical groups available at the CNC surface are a function of the extraction process used. For CNCs extracted with sulfuric acid, sulfate half-esters are key to their surface chemistry; for CNCs oxidised with the TEMPO reagent, carboxylic acids are key. Here, the functionalisation of CNCs with the conductive polymer PEDOT and with an amine-terminated polyether were both attempted. Moreover, to understand the results of these attempted functionalisation reactions, characterisation of the targeted surface groups was attempted. Various methods have been developed for characterising these surface groups, with conductometric titration chosen as the main focus of this work. Conductometric titration is attractive for its specificity and apparent simplicity. However, it was observed that the measurements from the titrations were significantly influenced by the addition of NaCl and HCl to the samples. This suggested the method’s sensitivity to conditions had been underestimated in previous CNC literature. Therefore, the conductometric titration of CNCs bearing both carboxylic acid and sulfate half-ester groups was investigated in more detail. Focus was given to how the results of these titrations are affected by the concentrations of NaCl and HCl in the sample. The findings indicate that the measurements from these titrations are strongly dependent on the chosen conditions. Further, the conventional approach of fitting tangent lines to the conductivity plot does not fully capture the effects occurring during these titrations. These insights show the need for nuanced analytical methods for accurate measurements of CNC surface chemistry with conductometric titration. These methods should give particular consideration to measurement conditions and the functional groups on the CNCs.","abstract_html":"Cellulose nanocrystals (CNCs) are elongated nanoscale crystalline particles able to be extracted from cellulose. They are noted for their combination of strength, stiffness, low density, and biodegradability, as well as emergent properties, such as forming birefringent liquid crystals. CNCs have found applications as a promising new nanomaterial, used in polymer composites, biocompatible scaffolds and optical materials. All these applications depend on the surface properties of CNCs, therefore reliable quantitative characterisation methods of these properties are required. The chemical groups available at the CNC surface are a function of the extraction process used. For CNCs extracted with sulfuric acid, sulfate half-esters are key to their surface chemistry; for CNCs oxidised with the TEMPO reagent, carboxylic acids are key. Here, the functionalisation of CNCs with the conductive polymer PEDOT and with an amine-terminated polyether were both attempted. Moreover, to understand the results of these attempted functionalisation reactions, characterisation of the targeted surface groups was attempted. Various methods have been developed for characterising these surface groups, with conductometric titration chosen as the main focus of this work. Conductometric titration is attractive for its specificity and apparent simplicity. However, it was observed that the measurements from the titrations were significantly influenced by the addition of NaCl and HCl to the samples. This suggested the method’s sensitivity to conditions had been underestimated in previous CNC literature. Therefore, the conductometric titration of CNCs bearing both carboxylic acid and sulfate half-ester groups was investigated in more detail. Focus was given to how the results of these titrations are affected by the concentrations of NaCl and HCl in the sample. The findings indicate that the measurements from these titrations are strongly dependent on the chosen conditions. Further, the conventional approach of fitting tangent lines to the conductivity plot does not fully capture the effects occurring during these titrations. These insights show the need for nuanced analytical methods for accurate measurements of CNC surface chemistry with conductometric titration. These methods should give particular consideration to measurement conditions and the functional groups on the CNCs.","abstract_has_math":false,"creators":["Teall, Benjamin"],"institution":"University of Cambridge","degree_name":"Doctor of Philosophy (PhD)","degree_level":"Doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Vignolini, Silvia"],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-02-27","date_published":"2025-02-27","updated_at":"2026-07-22T22:24:20Z","subjects":["Titration","Conductometric Titration","Cellulose","Cellulose Nanocrystals"],"languages":["eng"],"rights":[],"rights_urls":["https://www.repository.cam.ac.uk/bitstreams/9817537c-265c-4fd0-aa68-eed482c6c337/download","http://purl.org/NET/rdflicense/allrightsreserved"],"identifier_entries":[]},"links":{"outbound_url":"https://doi.org/10.17863/CAM.121633","outbound_label":"DOI","outbound_source":"dc:identifier.doi"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Vignolini, Silvia"]},{"key":"dc:creator","label":"Author","values":["Teall, Benjamin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2025-02-27"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cambridge"]},{"key":"dc:relation.isreferencedby.uri","label":"Dc Relation Isreferencedby URI","values":["https://www.repository.cam.ac.uk/handle/1810/389876"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Titration","Conductometric Titration","Cellulose","Cellulose Nanocrystals"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["https://www.repository.cam.ac.uk/bitstreams/9817537c-265c-4fd0-aa68-eed482c6c337/download","http://purl.org/NET/rdflicense/allrightsreserved"]},{"key":"dc:rights.embargodate","label":"Dc Rights Embargodate","values":["2026-09-24"]},{"key":"dc:rights.embargotype","label":"Dc Rights Embargotype","values":["embargo"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["https://doi.org/10.17863/CAM.121633"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://www.repository.cam.ac.uk/bitstreams/2ba8ef11-da50-41ae-a141-0858e6dfbcad/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Cellulose nanocrystals (CNCs) are elongated nanoscale crystalline particles able to be extracted from cellulose. 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Moreover, to understand the results of these attempted functionalisation reactions, characterisation of the targeted surface groups was attempted. Various methods have been developed for characterising these surface groups, with conductometric titration chosen as the main focus of this work. Conductometric titration is attractive for its specificity and apparent simplicity. However, it was observed that the measurements from the titrations were significantly influenced by the addition of NaCl and HCl to the samples. This suggested the method’s sensitivity to conditions had been underestimated in previous CNC literature. Therefore, the conductometric titration of CNCs bearing both carboxylic acid and sulfate half-ester groups was investigated in more detail. Focus was given to how the results of these titrations are affected by the concentrations of NaCl and HCl in the sample. The findings indicate that the measurements from these titrations are strongly dependent on the chosen conditions. Further, the conventional approach of fitting tangent lines to the conductivity plot does not fully capture the effects occurring during these titrations. These insights show the need for nuanced analytical methods for accurate measurements of CNC surface chemistry with conductometric titration. 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All these applications depend on the surface properties of CNCs, therefore reliable quantitative characterisation methods of these properties are required. The chemical groups available at the CNC surface are a function of the extraction process used. For CNCs extracted with sulfuric acid, sulfate half-esters are key to their surface chemistry; for CNCs oxidised with the TEMPO reagent, carboxylic acids are key. Here, the functionalisation of CNCs with the conductive polymer PEDOT and with an amine-terminated polyether were both attempted. Moreover, to understand the results of these attempted functionalisation reactions, characterisation of the targeted surface groups was attempted. Various methods have been developed for characterising these surface groups, with conductometric titration chosen as the main focus of this work. Conductometric titration is attractive for its specificity and apparent simplicity. However, it was observed that the measurements from the titrations were significantly influenced by the addition of NaCl and HCl to the samples. This suggested the method’s sensitivity to conditions had been underestimated in previous CNC literature. Therefore, the conductometric titration of CNCs bearing both carboxylic acid and sulfate half-ester groups was investigated in more detail. Focus was given to how the results of these titrations are affected by the concentrations of NaCl and HCl in the sample. The findings indicate that the measurements from these titrations are strongly dependent on the chosen conditions. Further, the conventional approach of fitting tangent lines to the conductivity plot does not fully capture the effects occurring during these titrations. These insights show the need for nuanced analytical methods for accurate measurements of CNC surface chemistry with conductometric titration. 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