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Cellulose photonics: designing functionality and optical appearance of natural materials

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cam.restrictionthesis_access_embargoed
cam.supervisorVignolini, Silvia
cam.supervisor.orcidVignolini, Silvia [0000-0003-0664-1418]
cam.thesis.fundingtrue
dc.contributor.authorGuidetti , Giulia
dc.contributor.orcidGuidetti , Giulia [0000-0002-6065-3359]
dc.date.accessioned2018-07-09T13:38:20Z
dc.date.available2018-07-09T13:38:20Z
dc.date.issued2018-07-20
dc.date.submitted2018-04-10
dc.date.updated2018-07-09T09:34:55Z
dc.description.abstractCellulose is the most abundant biopolymer on Earth as it is found in every plant cell wall; therefore, it represents one of the most promising natural resources for the fabrication of sustainable materials. In plants, cellulose is mainly used for structural integrity, however, some species organise cellulose in helicoidal nano-architectures generating strong iridescent colours. Recent research has shown that cellulose nanocrystals, CNCs, isolated from natural fibres, can spontaneously self-assemble into architectures that resemble the one producing colouration in plants. Therefore, CNCs are an ideal candidate for the development of new photonic materials that can find use to substitute conventional pigments, which are often harmful to humans and to the environment. However, various obstacles still prevent a widespread use of cellulose-based photonic structures. For instance, while the CNC films can display a wide range of colours, a precise control of the optical appearance is still difficult to achieve. The intrinsic low thermal stability and brittleness of cellulose-based films strongly limit their use as photonic pigments at the industrial scale. Moreover, it is challenging to integrate them into composites to obtain further functionality while preserving their optical response. In this thesis, I present a series of research contributions that make progress towards addressing these challenges. First, I use an external magnetic field to tune the CNC films scattering response. Then, I demonstrate how it is possible to tailor the optical appearance and the mechanical properties of the films as well as to enhance their functionality, by combining CNCs with other polymers. Finally, I study the thermal properties of CNC films to improve the retention of the helicoidal arrangement at high temperatures and to explore the potential use of this material in industrial fabrication processes, such as hot-melt extrusion.
dc.description.sponsorshipEngineering and Physical and Sciences Research Council and European Research Council grant awarded to Dr Silvia Vignolini
dc.identifier.doi10.17863/CAM.25252
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/277918
dc.language.isoen
dc.publisher.collegeQueens'
dc.publisher.departmentChemistry
dc.publisher.institutionUniversity of Cambridge
dc.rightsAttribution 4.0 International (CC BY 4.0)
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectcellulose photonics
dc.subjectcellulose nanocrystals
dc.subjectCNCs
dc.subjectcolloidal self-assembly
dc.subjectliquid crystals
dc.subjectcholesteric
dc.subjectbiomimetics
dc.subjectphotonic crystals
dc.subjectcolloids
dc.subjectstructural colour
dc.subjecthelicoidal films
dc.subjectchiral nematic
dc.subjectselective reflection
dc.subjectpitch
dc.subjectphotonic pigments
dc.subjectbiocompatible
dc.subjectsustainable
dc.subjectmagnetic fields
dc.subjectneodymium magnets
dc.subjectcholesteric axis orientation
dc.subjectbuckling
dc.subjectalignment
dc.subjectmonodomain
dc.subjectpolydomain
dc.subjectkinetic arrest
dc.subjectzwitterionic surfactants
dc.subjectcationic surfactants
dc.subjectelectrostatic interactions
dc.subjectDMPAS
dc.subjectflexible CNC films
dc.subjectcomposites
dc.subjectshape memory
dc.subjectpolydiolcitrates
dc.subjectPDDC-HD
dc.subjectinfiltration
dc.subjectsilk fibroin
dc.subjectco-assembly
dc.subjectcarbonisation
dc.subjectneutralisation
dc.subjectdesulphation
dc.subjectthermal stbaility
dc.subjectcarbon
dc.subjectamorphous carbon
dc.subjectcross-linking
dc.subjectdessication
dc.subjectpotassium hydroxide
dc.subjecthelicoidal carbon
dc.subjectoptical microscopy
dc.subjectelectron microscopy
dc.subjectcellulose hydrolysis
dc.titleCellulose photonics: designing functionality and optical appearance of natural materials
dc.typeThesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnameDoctor of Philosophy (PhD)
dc.type.qualificationtitlePhD in Chemistry

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