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Author:Kämäräinen, Tero
Title:Growth Kinetics and Stability of Self-Assembled Alkylsilane Monolayers on Cellulose Nanofibril Films
Nanofibrilloidulle selluloosakalvolle valmistetun itsejärjestyvän alkyylisilaaniyksikerroksen kasvukinetiikka ja stabiilius
Publication type:Master's thesis
Publication year:2014
Pages:vi + 41      Language:   eng
Department/School:Mikro- ja nanotekniikan laitos
Main subject:Mikro- ja nanotekniikka   (S3010)
Supervisor:Lipsanen, Harri
Instructor:Arcot, Lokanathan
Electronic version URL: http://urn.fi/URN:NBN:fi:aalto-201501031001
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  2504   | Archive
Keywords:nanocellulose
cellulose nanofibril
silane
hydrophobic patterns
self-assembled monolayer
growth kinetics
stability
nanoselluloosa
nanofibrilloitu selluloosa
silaani
hydrofobinen kuviointi
itsejärjestyvä yksikerros
kasvukinetiikka
stabiilius
Abstract (eng):Paper-based microfluidic sensors are becoming very popular in applications requiring chemical analysis.
This thesis deals with preliminary surface chemistry studies which form the foundation for development of cellulosic microfluidic devices.
Nanocellulose was chosen as the substrate and alkylsilanes were used to modify its wetting characteristics.

The growth kinetics of alkylsilane self-assembled monolayers (SAMs) prepared on cellulose nanofibril (CNF) film was studied.
The stability of the silane modification was tested in ambient environment, 50 and 100 % relative humidity, in alkaline and acidic vapour, and under 254 nm and 366 nm wavelength ultraviolet (UV) light irradiation.
The SAMs were also exposed to UV light in conjunction with its associated ozone (O3).
Protein and polyelectrolyte adsorption onto native and silane-modified CNF films was investigated.
Water contact angle measurements were used to characterize the wetting properties of the films, while atomic force microscopy was used to probe their surface morphology.
The chemical composition of the surfaces was analysed with X-ray photoelectron spectroscopy.

The silane-modifications proved largely stable in the above environments with the exception of UV/O3 treatment.
Hydrophilic-hydrophobic patterns were created on silane-modified CNF film using masked exposure to UV/O3, which degrades the alkyl chains of silanes at the mask opening.
The patterned film wetting characteristics turned out not to be applicable for fluid flow.
Abstract (fin):Paperipohjaista mikrofluidistiikkaa höydynnetään yhä enemmän kemiallista analyysia vaativissa sovelluksissa.
Tämä diplomityö käsittelee alustavaa pintakemiatutkimusta, joka luo pohjaa mikrofluidistiselle selluloosapinnalle.
Työn kohdepinnaksi valittiin nanoselluloosakalvo, jonka kastuvuutta muokattiin alkyylisilaaneilla.

Työssä tutkittiin nanofibrilloidulle selluloosakalvolle (engl. cellulose nanofibril, CNF) valmistetun alkyylisilaaniyksikerroksen kasvukinetiikkaa ja stabiiliutta.
Stabiiliutta tutkittiin säilyttämällä silaanikäsiteltyjä CNF kalvoja laboratorio-olosuhteissa, 50 ja 100 % suhteellisessa kosteudessa, emäksisessä ja happamassa höyryssä sekä altistamalla ne 254 nm ja 366 nm aallonpituiselle ultraviolettisäteilylle (UV-säteily).
Myös UV-säteilyn ja otsonin yhteisvaikutusta tutkittiin.
Lopuksi alkuperäisen ja silaanikäsitellyn CNF kalvon proteiinin ja polyelektrolyytin adsorptiokykyä analysoitiin.
Veden kontaktikulmamittauksilla karakterisoitiin pinnan kastuvuutta.
Atomivoimamikroskoopilla tutkittiin pinnan morfologiaa ja sen kemiallista koostumusta analysoitiin röntgenfotoelektronispektroskopian avulla.

CNF:n silaanikäsittely oli enimmäkseen stabiili edellä mainituissa ympäristöissä.
Silaanikäsitellyn CNF kalvon kastuvuus muutettiin osittain hydrofiiliseksi altistamalla se rajoitetusti UV-säteilylle ja otsonille, mikä hajottaa silaanien hydrofobiset alkyyliketjut maskin läpinäkyviltä kohdilta.
Kuvioidun silaanikäsitellyn CNF kalvon kastuvuusominaisuudet eivät sallineet sen käyttöä nestevirtauskanavana.
ED:2015-01-18
INSSI record number: 50386
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