Cellulose Nanofibril Films as Bioinspired Membranes: Capitalizing on Water Interactions: Dissertation

Minna Hakalahti

    Research output: ThesisDissertationMonograph

    Abstract

    This work represents an effort to exploit the inherent features of nanoscaled cellulose as practical advantages in membrane materials. The approach was to systematically explore the behavior of 2,2,6,6-tetramethylpiperidine-1-oxyl radical oxidized cellulose nanofibrils (TEMPO CNF) with respect to water vapor sorption mechanisms and transport of water, to tune the inherent properties using facile strategies and to expose the materials to performance testing. Surface-sensitive methods were used for revealing molecular scale phenomena directly at interfaces, whereas bulk methods were used to demonstrate their significance in macroscopic scale. Films made from TEMP O CNF were in the main role, complemented by synthetic polymers to introduce new performance features with significance for membrane materials. Water vapor sorption of TEMPO CNF thin films was studied by precise surface-sensitive analytical methods, i.e. quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry, and combined with classical physicochemical models. It was established that water vapor sorption into TEMPO CNF thin films occurs through distinct underlying mechanisms: specific sorption below 10% RH, association of Flory-Huggins population of molecules with the films at 10-75% RH and clustering of water molecules above 75% RH. Kinetic parameters defining the transport of water molecules in the TEMPO CNF film structure were determined. The results showed that diffusion of water vapor could be used as a probing tool for elucidating structural details of moisture-responsive materials in the presence of water. Bulk and interfacial chemical modification approaches were applied. Enhancement of wet strength of TEMPO CNF films was achieved by crosslinking, whereby inherent characteristics, such as hydrophilicity, were not compromised. The water stable structure was suitable for further functionalization with a thermoresponsive polymer, poly(NIPAM). Covering mere 8% of the surface with poly(NIPAM) caused drastic changes in the performance of the TEMPO CNF film, as the increment in slope of relative water permeance around the lower critical solution temperature of poly(NIPAM) increased from 18% to 100%, showcasing the efficiency of the interfacial modification approach. CNF films were also subjected to performance testing in tetrahydrofuran and n-hexane, whereby their suitability for organic solvent nanofiltration was demonstrated. This thesis furthers the fundamental understanding of water interactions of cellulosic nanomaterials and other complex moisture-sensitive structures in the biomaterial genre. It also proposes concrete means to tune selected material properties toward desired environments and effects. In the view of this thesis, inherent structure-derived properties are the key for achieving performance features that will carry future biomaterials development beyond conventional
    applications.
    Original languageEnglish
    QualificationDoctor Degree
    Awarding Institution
    • Aalto University
    Supervisors/Advisors
    • Kontturi, Eero, Supervisor, External person
    • Tammelin, Tekla, Advisor
    Award date23 Feb 2018
    Place of PublicationHelsinki
    Publisher
    Print ISBNs978-952-60-7856-4, 978-951-38-8619-6
    Electronic ISBNs978-952-60-7857-1, 978-951-38-8618-9
    Publication statusPublished - 23 Feb 2018
    MoE publication typeG4 Doctoral dissertation (monograph)

    Fingerprint

    Cellulose films
    oxidized cellulose
    Membranes
    Steam
    Water
    Sorption
    Biocompatible Materials
    Molecules
    Polymers
    Moisture
    Thin films
    Nanofiltration
    Spectroscopic ellipsometry
    Quartz crystal microbalances
    Chemical modification
    Hydrophilicity
    Testing
    Kinetic parameters
    Nanostructured materials
    Cellulose

    Keywords

    • cellulose nanofibrils
    • water interactions
    • films
    • membranes
    • surface-sensitive techniques

    Cite this

    @phdthesis{d1e078dcce4648738abe3ec2a3c59d88,
    title = "Cellulose Nanofibril Films as Bioinspired Membranes: Capitalizing on Water Interactions: Dissertation",
    abstract = "This work represents an effort to exploit the inherent features of nanoscaled cellulose as practical advantages in membrane materials. The approach was to systematically explore the behavior of 2,2,6,6-tetramethylpiperidine-1-oxyl radical oxidized cellulose nanofibrils (TEMPO CNF) with respect to water vapor sorption mechanisms and transport of water, to tune the inherent properties using facile strategies and to expose the materials to performance testing. Surface-sensitive methods were used for revealing molecular scale phenomena directly at interfaces, whereas bulk methods were used to demonstrate their significance in macroscopic scale. Films made from TEMP O CNF were in the main role, complemented by synthetic polymers to introduce new performance features with significance for membrane materials. Water vapor sorption of TEMPO CNF thin films was studied by precise surface-sensitive analytical methods, i.e. quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry, and combined with classical physicochemical models. It was established that water vapor sorption into TEMPO CNF thin films occurs through distinct underlying mechanisms: specific sorption below 10{\%} RH, association of Flory-Huggins population of molecules with the films at 10-75{\%} RH and clustering of water molecules above 75{\%} RH. Kinetic parameters defining the transport of water molecules in the TEMPO CNF film structure were determined. The results showed that diffusion of water vapor could be used as a probing tool for elucidating structural details of moisture-responsive materials in the presence of water. Bulk and interfacial chemical modification approaches were applied. Enhancement of wet strength of TEMPO CNF films was achieved by crosslinking, whereby inherent characteristics, such as hydrophilicity, were not compromised. The water stable structure was suitable for further functionalization with a thermoresponsive polymer, poly(NIPAM). Covering mere 8{\%} of the surface with poly(NIPAM) caused drastic changes in the performance of the TEMPO CNF film, as the increment in slope of relative water permeance around the lower critical solution temperature of poly(NIPAM) increased from 18{\%} to 100{\%}, showcasing the efficiency of the interfacial modification approach. CNF films were also subjected to performance testing in tetrahydrofuran and n-hexane, whereby their suitability for organic solvent nanofiltration was demonstrated. This thesis furthers the fundamental understanding of water interactions of cellulosic nanomaterials and other complex moisture-sensitive structures in the biomaterial genre. It also proposes concrete means to tune selected material properties toward desired environments and effects. In the view of this thesis, inherent structure-derived properties are the key for achieving performance features that will carry future biomaterials development beyond conventionalapplications.",
    keywords = "cellulose nanofibrils, water interactions, films, membranes, surface-sensitive techniques",
    author = "Minna Hakalahti",
    year = "2018",
    month = "2",
    day = "23",
    language = "English",
    isbn = "978-952-60-7856-4",
    series = "VTT Science",
    publisher = "Aalto University",
    number = "171",
    address = "Finland",
    school = "Aalto University",

    }

    Cellulose Nanofibril Films as Bioinspired Membranes : Capitalizing on Water Interactions: Dissertation. / Hakalahti, Minna.

    Helsinki : Aalto University, 2018. 164 p.

    Research output: ThesisDissertationMonograph

    TY - THES

    T1 - Cellulose Nanofibril Films as Bioinspired Membranes

    T2 - Capitalizing on Water Interactions: Dissertation

    AU - Hakalahti, Minna

    PY - 2018/2/23

    Y1 - 2018/2/23

    N2 - This work represents an effort to exploit the inherent features of nanoscaled cellulose as practical advantages in membrane materials. The approach was to systematically explore the behavior of 2,2,6,6-tetramethylpiperidine-1-oxyl radical oxidized cellulose nanofibrils (TEMPO CNF) with respect to water vapor sorption mechanisms and transport of water, to tune the inherent properties using facile strategies and to expose the materials to performance testing. Surface-sensitive methods were used for revealing molecular scale phenomena directly at interfaces, whereas bulk methods were used to demonstrate their significance in macroscopic scale. Films made from TEMP O CNF were in the main role, complemented by synthetic polymers to introduce new performance features with significance for membrane materials. Water vapor sorption of TEMPO CNF thin films was studied by precise surface-sensitive analytical methods, i.e. quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry, and combined with classical physicochemical models. It was established that water vapor sorption into TEMPO CNF thin films occurs through distinct underlying mechanisms: specific sorption below 10% RH, association of Flory-Huggins population of molecules with the films at 10-75% RH and clustering of water molecules above 75% RH. Kinetic parameters defining the transport of water molecules in the TEMPO CNF film structure were determined. The results showed that diffusion of water vapor could be used as a probing tool for elucidating structural details of moisture-responsive materials in the presence of water. Bulk and interfacial chemical modification approaches were applied. Enhancement of wet strength of TEMPO CNF films was achieved by crosslinking, whereby inherent characteristics, such as hydrophilicity, were not compromised. The water stable structure was suitable for further functionalization with a thermoresponsive polymer, poly(NIPAM). Covering mere 8% of the surface with poly(NIPAM) caused drastic changes in the performance of the TEMPO CNF film, as the increment in slope of relative water permeance around the lower critical solution temperature of poly(NIPAM) increased from 18% to 100%, showcasing the efficiency of the interfacial modification approach. CNF films were also subjected to performance testing in tetrahydrofuran and n-hexane, whereby their suitability for organic solvent nanofiltration was demonstrated. This thesis furthers the fundamental understanding of water interactions of cellulosic nanomaterials and other complex moisture-sensitive structures in the biomaterial genre. It also proposes concrete means to tune selected material properties toward desired environments and effects. In the view of this thesis, inherent structure-derived properties are the key for achieving performance features that will carry future biomaterials development beyond conventionalapplications.

    AB - This work represents an effort to exploit the inherent features of nanoscaled cellulose as practical advantages in membrane materials. The approach was to systematically explore the behavior of 2,2,6,6-tetramethylpiperidine-1-oxyl radical oxidized cellulose nanofibrils (TEMPO CNF) with respect to water vapor sorption mechanisms and transport of water, to tune the inherent properties using facile strategies and to expose the materials to performance testing. Surface-sensitive methods were used for revealing molecular scale phenomena directly at interfaces, whereas bulk methods were used to demonstrate their significance in macroscopic scale. Films made from TEMP O CNF were in the main role, complemented by synthetic polymers to introduce new performance features with significance for membrane materials. Water vapor sorption of TEMPO CNF thin films was studied by precise surface-sensitive analytical methods, i.e. quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry, and combined with classical physicochemical models. It was established that water vapor sorption into TEMPO CNF thin films occurs through distinct underlying mechanisms: specific sorption below 10% RH, association of Flory-Huggins population of molecules with the films at 10-75% RH and clustering of water molecules above 75% RH. Kinetic parameters defining the transport of water molecules in the TEMPO CNF film structure were determined. The results showed that diffusion of water vapor could be used as a probing tool for elucidating structural details of moisture-responsive materials in the presence of water. Bulk and interfacial chemical modification approaches were applied. Enhancement of wet strength of TEMPO CNF films was achieved by crosslinking, whereby inherent characteristics, such as hydrophilicity, were not compromised. The water stable structure was suitable for further functionalization with a thermoresponsive polymer, poly(NIPAM). Covering mere 8% of the surface with poly(NIPAM) caused drastic changes in the performance of the TEMPO CNF film, as the increment in slope of relative water permeance around the lower critical solution temperature of poly(NIPAM) increased from 18% to 100%, showcasing the efficiency of the interfacial modification approach. CNF films were also subjected to performance testing in tetrahydrofuran and n-hexane, whereby their suitability for organic solvent nanofiltration was demonstrated. This thesis furthers the fundamental understanding of water interactions of cellulosic nanomaterials and other complex moisture-sensitive structures in the biomaterial genre. It also proposes concrete means to tune selected material properties toward desired environments and effects. In the view of this thesis, inherent structure-derived properties are the key for achieving performance features that will carry future biomaterials development beyond conventionalapplications.

    KW - cellulose nanofibrils

    KW - water interactions

    KW - films

    KW - membranes

    KW - surface-sensitive techniques

    M3 - Dissertation

    SN - 978-952-60-7856-4

    SN - 978-951-38-8619-6

    T3 - VTT Science

    PB - Aalto University

    CY - Helsinki

    ER -