Cellulose Nanofibrils as a Functional Material

Marjo Kettunen

Cellulose Nanofibrils as a Functional Material

Julkaisun otsikon käännös: Selluloosan Nanokuidut Funktionaalisena Materiaalina

Marjo Kettunen

Teknillisen fysiikan laitos

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Tässä työssä selluloosan nanokuidusta on valmistettu funktionaalisia ja ulkoisiin olosuhteisiin, reagoivia materiaaleja. Nanoselluloosa on materiaalitieteen kannalta kiinnostava sen mekaanisen lujuuden, nanoskaalan kuiturakenteen, uusiutuvan alkuperän, sekä biologisen yhteensopivuuden vuoksi. Lisäksi nanoselluloosan suuri ominaispinta-ala, ja kuidun pinnalla olevat lukuisat kemiallisesti tai fysikaalisesti muokattavat ryhmät mahdollistavat mitä moninaisimpia funktionaalisia nanoselluloosamateriaaleja. Natiivin selluloosan nanokuitujen kykyä muodostaa vahvoja hydrogeelejä hyvin alhaisilla konsentraatioilla on tutkittu julkaisussa I. Niiden osoitettiin olevan lujia ja voimakkaasti leikkausohenevia, mikä on tärkeää materiaalien valmistus- ja prosessointimenetelmissä sekä sovelluksissa. Julkaisussa II havainnolistettiin, miten vahva hydrogeeli voidaan kuivata kylmäkuivauksella, jolloin muodostuu aerogeelejä. Natiivin selluloosan nanokuiduista valmistetut aerogeelit ovat muokkautuvia ja taipuisia, huolimatta niiden 98 % huokoisuudesta. Niiden sisärakennetta ja huokoisuutta voidaan muunnella mm. kuivausolosuhteiden avulla, minkä vuoksi ne soveltuvat mitä erilaisimpiin käyttötarkoituksiin. Ne tarjoavat esimerkiksi perkoloivan substraatin johtavalle polymeerille, kuten polyaniliinille, jonka avulla saavutettiin erittäin huokoinen sähköisesti johtava nanoselluloosamateriaali. Lisäksi, päällystämällä aerogeeli titaanidioksilla (TiO2), sen ominaisuuksia voidaan ohjata ulkoisesti. Julkaisussa III osoitettiin, että TiO2-pinnoitetut nanoselluloosa-aerogeelit muuttuvat UV-valon vaikutuksesta vettä hylkivästä vettä superabsorboiviksi. Aerogeelin vaikutus on kaksijakoinen: se toimii sekä alustana että tehostaa omalla rakenteellaan pinnoitteen aiheuttamia ominaisuuksia. Myös TiO2-nanoselluloosa-aerogeelin hyvä fotokatalyyttinen aktiivisuus perustuu suurehkoon ominaispinta-alaan ja hierarkkiseen huokoisuuteen. Julkaisussa IV tarkasteltiin edelleen nanoselluloosa-aerogeelin rakenteen ja huokoisuuden merkitystä niin hydrofobisuuteen kuin myös oleofobisuuteen fluoraamalla aerogeeli. Julkaisussa V havainnollistetaan miten hydrofobiseksi TiO2:lla pinnoitettu nanoselluloosa-aerogeeli absorboi selektiivisesti öljyä, mutta hylkii vettä. Tällaista veden pinnalla kelluvaa, öljyä imevää materiaalia voidaan käyttää esim. öljyn poistamiseen vedestä öljyvahingoissa. Tässä työssä tutkitut funktionalisoidut nanoselluloosamateriaalit tarjoavat mahdollisuuksia uusiin erityissovellutuksiin materiaalitieteessä, ja yhtälailla nanoselluloosa luo mahdollisuuksia metsäteollisuuden kilpailukyvyn vahvistamiseen sen muuttuvassa ja haastavassa toimintaympäristössä.

Julkaisun otsikon käännös	Selluloosan Nanokuidut Funktionaalisena Materiaalina
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Ikkala, Olli, Vastuuprofessori Ikkala, Olli, Ohjaaja
Kustantaja	Aalto University
Painoksen ISBN	978-952-60-5255-7
Sähköinen ISBN	978-952-60-5256-4
Tila	Julkaistu - 2013
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

nanoselluloosa
nanofibrillaarinen selluloosa
mikrofibrillaarinen selluloosa
aerogeeli
valo-ohjautuva absorptio
selektiivinen absorptio

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-60-5256-4

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@phdthesis{96302588d945482f82385b1f7d6dd218,

title = "Cellulose Nanofibrils as a Functional Material",

abstract = "The recent developments to disintegrate nanocelluloses from plant and wood cell materials have attracted considerable interest in materials science. Nanocelluloses are considered as fascinating building blocks for functional materials, thanks to their high mechanical properties, rod-like or fibrous structure, biocompatibility and sustainability. In addition, they own high surface area with numerous free reactive groups offering great opportunities for chemical or physical functionalization. Among nanocelluloses, native cellulose nanofibrils form an important class of materials, and this thesis explores them as building blocks for functional and responsive materials. The characteristics of enzymatically and mechanically prepared cellulose nanofibrils are studied in Publication I. The cellulose nanofibrils form strong inherent hydrogels at low concentration without chemical cross-linking, and show shear thinning which is useful both in processing and in applicability. Publication II demonstrates that the hydrogel enables vacuum freeze-drying to form light-weight aerogels which are ductile and deformable, even if the porosity totals 98%. The tunable morphology provides multiple length scale structures and porosity, as well as percolative template for conducting polymer, e.g. polyaniline to achieve highly porous conducting materials. The aerogels, made from the long and entangled cellulose nanofibrils, are also versatile templates for titanium dioxide (TiO2) and fluorosilane deposition to tune the wetting, and to enable responsive materials. In Publication III, the TiO2-coated nanocellulose aerogel shows switchable water absorption between nonabsorbent and superabsorbent states upon exposure of UV light. In addition, TiO2-coated aerogel shows improved photo-catalytic activity. The aerogel template not only serves as a support for TiO2 but also enhances the effects due to its multiple scale structures. The superoleophobic and -hydrophobic bio-inspired nanocellulose cargo carrier, reported in Publication IV, is also shown to benefit from multiple length scaled structures and the pores. The TiO2 approach is extended in Publication V, where the selective absorption of TiO2-coated nanocellulose aerogels is applied, and floatable oil-absorbing nanocellulose aerogel is demonstrated for oil spill removal. This thesis contributes to basic research on nanocelluloses, while yielding concrete benefits for the industrial context. It furthers the fundamental understanding of the behavior of cellulose nanofibrils, and suggests novel value-added applications beyond the classic cellulose applications. Nanocellulose can lead to strengthened competitiveness of the forest industry in its changing operational environment.",

keywords = "nanocellulose, microfibrillated cellulose, aerogel, foam, UV-switchable absorption, selective absorption, nanoselluloosa, nanofibrillaarinen selluloosa, mikrofibrillaarinen selluloosa, aerogeeli, valo-ohjautuva absorptio, selektiivinen absorptio, nanocellulose, microfibrillated cellulose, aerogel, foam, UV-switchable absorption, selective absorption",

author = "Marjo Kettunen",

year = "2013",

language = "English",

isbn = "978-952-60-5255-7",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "114",

address = "Finland",

school = "Aalto University",

}

TY - BOOK

T1 - Cellulose Nanofibrils as a Functional Material

AU - Kettunen, Marjo

PY - 2013

Y1 - 2013

N2 - The recent developments to disintegrate nanocelluloses from plant and wood cell materials have attracted considerable interest in materials science. Nanocelluloses are considered as fascinating building blocks for functional materials, thanks to their high mechanical properties, rod-like or fibrous structure, biocompatibility and sustainability. In addition, they own high surface area with numerous free reactive groups offering great opportunities for chemical or physical functionalization. Among nanocelluloses, native cellulose nanofibrils form an important class of materials, and this thesis explores them as building blocks for functional and responsive materials. The characteristics of enzymatically and mechanically prepared cellulose nanofibrils are studied in Publication I. The cellulose nanofibrils form strong inherent hydrogels at low concentration without chemical cross-linking, and show shear thinning which is useful both in processing and in applicability. Publication II demonstrates that the hydrogel enables vacuum freeze-drying to form light-weight aerogels which are ductile and deformable, even if the porosity totals 98%. The tunable morphology provides multiple length scale structures and porosity, as well as percolative template for conducting polymer, e.g. polyaniline to achieve highly porous conducting materials. The aerogels, made from the long and entangled cellulose nanofibrils, are also versatile templates for titanium dioxide (TiO2) and fluorosilane deposition to tune the wetting, and to enable responsive materials. In Publication III, the TiO2-coated nanocellulose aerogel shows switchable water absorption between nonabsorbent and superabsorbent states upon exposure of UV light. In addition, TiO2-coated aerogel shows improved photo-catalytic activity. The aerogel template not only serves as a support for TiO2 but also enhances the effects due to its multiple scale structures. The superoleophobic and -hydrophobic bio-inspired nanocellulose cargo carrier, reported in Publication IV, is also shown to benefit from multiple length scaled structures and the pores. The TiO2 approach is extended in Publication V, where the selective absorption of TiO2-coated nanocellulose aerogels is applied, and floatable oil-absorbing nanocellulose aerogel is demonstrated for oil spill removal. This thesis contributes to basic research on nanocelluloses, while yielding concrete benefits for the industrial context. It furthers the fundamental understanding of the behavior of cellulose nanofibrils, and suggests novel value-added applications beyond the classic cellulose applications. Nanocellulose can lead to strengthened competitiveness of the forest industry in its changing operational environment.

AB - The recent developments to disintegrate nanocelluloses from plant and wood cell materials have attracted considerable interest in materials science. Nanocelluloses are considered as fascinating building blocks for functional materials, thanks to their high mechanical properties, rod-like or fibrous structure, biocompatibility and sustainability. In addition, they own high surface area with numerous free reactive groups offering great opportunities for chemical or physical functionalization. Among nanocelluloses, native cellulose nanofibrils form an important class of materials, and this thesis explores them as building blocks for functional and responsive materials. The characteristics of enzymatically and mechanically prepared cellulose nanofibrils are studied in Publication I. The cellulose nanofibrils form strong inherent hydrogels at low concentration without chemical cross-linking, and show shear thinning which is useful both in processing and in applicability. Publication II demonstrates that the hydrogel enables vacuum freeze-drying to form light-weight aerogels which are ductile and deformable, even if the porosity totals 98%. The tunable morphology provides multiple length scale structures and porosity, as well as percolative template for conducting polymer, e.g. polyaniline to achieve highly porous conducting materials. The aerogels, made from the long and entangled cellulose nanofibrils, are also versatile templates for titanium dioxide (TiO2) and fluorosilane deposition to tune the wetting, and to enable responsive materials. In Publication III, the TiO2-coated nanocellulose aerogel shows switchable water absorption between nonabsorbent and superabsorbent states upon exposure of UV light. In addition, TiO2-coated aerogel shows improved photo-catalytic activity. The aerogel template not only serves as a support for TiO2 but also enhances the effects due to its multiple scale structures. The superoleophobic and -hydrophobic bio-inspired nanocellulose cargo carrier, reported in Publication IV, is also shown to benefit from multiple length scaled structures and the pores. The TiO2 approach is extended in Publication V, where the selective absorption of TiO2-coated nanocellulose aerogels is applied, and floatable oil-absorbing nanocellulose aerogel is demonstrated for oil spill removal. This thesis contributes to basic research on nanocelluloses, while yielding concrete benefits for the industrial context. It furthers the fundamental understanding of the behavior of cellulose nanofibrils, and suggests novel value-added applications beyond the classic cellulose applications. Nanocellulose can lead to strengthened competitiveness of the forest industry in its changing operational environment.

KW - nanocellulose

KW - microfibrillated cellulose

KW - aerogel

KW - foam

KW - UV-switchable absorption

KW - selective absorption

KW - nanoselluloosa

KW - nanofibrillaarinen selluloosa

KW - mikrofibrillaarinen selluloosa

KW - aerogeeli

KW - valo-ohjautuva absorptio

KW - selektiivinen absorptio

KW - nanocellulose

KW - microfibrillated cellulose

KW - aerogel

KW - foam

KW - UV-switchable absorption

KW - selective absorption

M3 - Doctoral Thesis

SN - 978-952-60-5255-7

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Cellulose Nanofibrils as a Functional Material

Abstrakti

Tutkimusalat

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