Cellulose nanocomposites offer interesting potential in terms of improved properties and new functionalities compared with microcomposites. Preparation from colloidal suspensions is promising, since high reinforcement content is possible and a wide range of constituents can be used. In the first study, the challenge is to form a stable suspension of well-dispersed carbon nanotubes (CNT) and nanofibrillated cellulose (NFC) in water and to prepare commingled high CNT content nanopaper structures by filtration. Various surfactants were used to modify CNT. The NFC was stabilized by charged carboxylate groups. A nonylphenol phosphate ester surfactant, NPPE, worked well for CNT and provided a stable and well-dispersed water suspension of CNT and NFC. Field emission scanning electron microscopy (FE-SEM), porosimetry and atomic force microscopy (AFM) were used to characterize nanopaper structure, and tensile properties were measured as well as surface resistivity. The processing route is water based and it is possible to prepare thin coatings as well as thicker films with a combination of low surface resistivity, flexibility in bending and high strength and toughness in tension.  As inspired by organo-modified layered silicates, the objective of the second study is to develop an environmentally friendly procedure for the surface modification of cellulose nanocrystals, CNC, using quaternary ammonium salts via adsorption. In order to obtain higher surface charge density on CNC, a new route is developed for preparation of CNC with carboxylic acid groups. Quanternary ammonium cations bearing alkyl, phenyl, glycidyl, and diallyl groups are used to modify CNC to render their surface more hydrophobic. The structure and surface hydrophobicity of unmodified and modified CNC as well as their dispersibility in organic solvent are characterized by AFM, FE-SEM, Fourier-transformed infrared spectroscopy (FT-IR), X-Ray analysis (XDR) and contact angle measurement (CAM). Future work will focus on surface-modified nanocelluloses in composite materials, in order to learn more about surface treatment effects on nanocomposite properties. / Nanokompositer från cellulosa har potential att ge starkt förbättrade egenskaper och ny funktionalitet jämfört med mikrokompositer. De ger även möjlighet till komposittillverkning från kolloidala suspensioner där man kan uppnå hög halt av förstärkningsfasen. Det är också möjligt att välja från en bred flora av lösliga och dispergerbara materialkomponenter. I första studien är utmaningen att skapa en stabil och väldispergerad suspension av kolnanorör (CNT) och nanofibrillerad cellulosa (NFC) i vatten för att genom filtrering framställa nanopapper med interpenetrerande CNT och NFC nätverk. Olika ytaktiva ämnen användes för att modifiera CNT. NFC stabiliserades genom laddade karboxylgrupper på ytan. En nonylfenol fosfatester, NPPE, fungerade bra för CNT och resulterade i en stabil och väldispergerad vattensuspension av CNT och NFC. FE-SEM, densitometri och AFM användes för att karakterisera nanopapperstruktur. Mekaniska egenskaper och ytresistivitet mättes. Processen för framställning av CNT/NFC nanopapper är vattenbaserade och det är möjligt att framställa tunna ytbeläggningar likväl som tjockare filmer. Dessa strukturer har en kombination av låg resistivitet, flexibilitet i böjning liksom hög hållfasthet och seghet i dragbelastning.  Syftet med den andra studien är att utgå från organo-modifierade skiktade silikater (leror) för att utveckla en miljövänlig ytmodifieringsmetod för nanocellulosa. För att öka ytladdningstätheten på CNC (nanokristaller från cellulosa) utvecklas ett nytt sätt att skapa karboxylgrupper på ytan. Kvarternära ammoniumsalter med alkyl, fenyl, glycidyl och diallylgrupper används för att göra ytan på CNC mer hydrofob. Ytans struktur och hydrofoba karaktär, liksom dispersionsegenskaper i organiska lösningsmedel, karakteriseras med hjälp av AFM, FE-SEM, FT-IR, XDR och kontaktvinkelmätning. Fortsatt arbete kommer att fokusera på ytmodifierad cellulosa i kompositmaterial, för att utveckla förståelsen för effekter av ytmodifiering på nanokompositers egenskaper / <p>QC 20120302</p>

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20449号 / 農博第2234号 / 新制||農||1050(附属図書館) / 学位論文||H29||N5070(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 矢野 浩之, 教授 木村 恒久, 教授 髙野 俊幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

A host of environmental issues will define the state of the environment in the 21st century, with plastic pollution and water shortages among them. While solutions to these problems require large-scale, multipronged solutions, one way we can address them is through material innovation and the use of nanoparticles. In the first project, we address the issue of plastic pollution by creating nanocomposites of biodegradable polymers (PLA and PCL) with cellulose nanofibrils. Here, PLA and PCL are grafted from the surface of cellulose nanofibrils via ring-opening polymerization of cyclic ester monomers. Polymer-grafted cellulose (PGC) is characterized with structural analysis, solubility tests, thermal properties. Graft-polymer and generated free polymer are compared to evaluate assumptions about polymerization kinetics. Lastly, environmental fate of PGC is evaluated via aerobic, anaerobic, and enzymatic biodegradation tests. In the second project, we address the issue of fresh water shortage by creating screen-printed composites of polymerizable, surfactant-templated single-wall carbon nanotubes (SWNTs). Surfactant-templated SWNTs behave as lyotropic liquid crystals (LLCs), allowing self-assembly and shear-directed alignment. Here, LLC-SWNT inks are screen-printed in micron-sized channels and polymerized with UV light. Mesophase and alignment are evaluated using SAXS. Certain methods of screen printing with a stencil are found to enhance alignment and ordering of LLC-SWNTs, allowing for enhanced desalination and ion rejection.

The process of TEMPO-mediated oxidation has gained broad usage towards the preparation of highly charged, carboxyl-functionalized polysaccharides. TEMPO-oxidized nanocelluloses (TONc) of high surface charge and measuring 3 to 5 nm in width have been recently prepared from TEMPO-oxidized pulp. This study examines as-produced and surface-hydrophobized TONc as reinforcing additives in cellulosic polymer matrices. In the first part of the work, covalent (amidation) and non-covalent (ionic complexation) coupling were compared as treatment techniques for the hydrophobization of TONc surfaces with octadecylamine (ODA). Subsequently, TONc and its covalently coupled derivative were evaluated as nanofiber reinforcements in a cellulose acetate butyrate (CAB) matrix. The properties of the resulting nanocomposites were compared with those of similarly prepared ones reinforced with conventional microfibrillated cellulose (MFC). It was found that both ionic complexation and amidation resulted in complete conversion of carboxylate groups on TONc surfaces. As a result of surface modification, the net crystallinity of TONc was lowered by 15 to 25% but its thermal decomposition properties were not significantly altered. With respect to nanocomposite performance, the maximum TONc reinforcement of 5 vol % produced negligible changes to the optical transmittance behavior and a 22-fold increase in tensile storage modulus in the glass transition region of CAB. In contrast, hydrophobized TONc and MFC deteriorated the optical transmittance of CAB by ca 20% and increased its tensile storage modulus in the glass transition region by only 3.5 and 7 times respectively. These differences in nanocomposite properties were attributed to homogeneous dispersion of TONc compared to aggregation of both the hydrophobized derivative and the MFC reference in CAB matrix. A related study comparing TONc with MFC and cellulose nanocrystals (CNC) as reinforcements in hydroxypropylcellulose (HPC), showed TONc reinforcements as producing the most significant changes to HPC properties. The results of dynamic mechanical analysis and creep compliance measurements could be interpreted based on similar arguments as those made for the CAB-based nanocomposites. Overall, this work revealed that the use of TONc (without the need for surface hydrophobization) as additives in cellulosic polymer matrices leads to superior reinforcing capacity and preservation of matrix transparency compared to the use of conventional nanocelluloses. / Ph. D.

History teaches us that novel materials, such as chlorofluorocarbon and asbestos, can have dire unintended consequences to human and environmental health. The exponential growth of the field of nanotechnology and the products developed along the way provide the opportunity for a new paradigm of design thinking, in which human and environmental impacts are considered early on in product development. In particular, nanocellulose is touted as a promising green nanomaterial, as it is sourced from an effectively inexhaustible feedstock of wood-based cellulose and is assumed to be harmless to the environment since it is derived from a natural material and assumed to be biodegradable. The various forms of nanocellulose possess an impressive diversity of properties, making it suitable for a wide variety of applications such as drug delivery, reinforcement, food additives, and iridescent make-up. However, as nanomaterials can have different properties relative to their bulk form, it is questionable whether they are truly environmentally friendly, particularly in terms of their biodegradability and potential impacts to receiving environments. Given the projected mass-scale application of nanocellulose and the inevitability of its subsequent release into environment, the purpose of this study was to determine the biodegradability of nanocellulose and the response of environmentally-relevant microbial communities. Specifically, it was hypothesized that cellulose in the nano size range would display distinct biodegradation patterns and rates, relative to larger forms of cellulose. Further, it was hypothesized that modification of nanocellulose, in terms of morphology and surface properties (e.g., charge), would further influence its biodegradability. Wetlands and anaerobic digesters were selected as two environmentally-relevant receiving environments that also play critical roles in global carbon turnover. To examine the biodegradability of nanocellulose, two distinct microbial consortia were enriched from wetland (W) and anaerobic digester (AD) inocula and applied in parallel experiments. The consortia were grown under anaerobic conditions with microcrystalline cellulose as the sole carbon substrate over a period of 246 days before being aliquoted to microcosms for subsequent biodegradation assays. Various forms of nanocellulose were spiked into the microcosms and compared with microcrystalline cellulose as a non nano reference. Microcosms were sacrificed in triplicate with time to monitor cellulose degradation as well as various measures of microbial community response. Microbial communities were characterized in terms of gene markers for total bacteria (16S rRNA genes) and anaerobic cellulose degraders (glycoside hydrolase family 48 genes, i.e., cel48) as well as high throughput amplicon sequencing of 16S rRNA genes (V4 region). A series of three studies examined: 1) the effect of nanocrystalline versus microcrystalline cellulose; 2) the effects of nanocellulose morphology (crystalline rod versus filament) and surface functionalization (cationic and anionic); and 3) metagenomic characterization of cellulose degrading communities using next-generation DNA sequencing. It was found that the nano- size range did not hinder cellulose degradation, in fact, nanocrystalline cellulose degraded slightly faster than microcrystalline cellulose according to 1st order kinetics (1st order decay constants: 0.62±0.08 wk-1 for anionic nanocrystalline cellulose versus 0.39±0.05 wk-1 for microcrystalline cellulose exposed to AD culture; 0.69±0.04 wk-1 for anionic nanocrystalline cellulose versus 0.58±0.05 wk-1 for microcrystalline cellulose exposed to W). Experiments comparing the effects of surface functionalization indicated that anionic nanocellulose degraded faster than cationic cellulose (1st order decay constants for cationic nanocrystalline cellulose: 0.48±0.06 wk-1 and 0.58±0.07 wk-1 on exposure to AD and W cultures respectively). Measurements of 16S rRNA and cel48 genes were consistent with this trend of greater biological growth and cellulose-degrading potential in the anionic nanocellulose condition, suggesting that surface properties can influence biodegradation patterns. Taxonomic characterization of 16S rRNA gene amplicons suggested that taxa known to contain anaerobic cellulose degraders were enriched in both W and AD consortia, which shifted in a distinct manner in response to exposure to the different cellulosic materials. This suggests that distinct groups of microbes may drive the biodegradation of different forms of cellulose. Further, metagenomic investigation provided new insight into taxonomic and functional aspects of anaerobic cellulose degradation, including identification of enzymatic families associated with degradation of the various forms of cellulose. Overall, the findings of this study advance understanding of anaerobic cellulose degradation and indicate that nanocellulose is likely to readily degrade in receiving environments and not pose an environmental concern. / Ph. D.

Nanocellulose is a nascent and promising material with many exceptional properties and a broad spectrum of potential applications; hence, it has drawn increasing research interests in the past decade.  A new type of nanocellulose -- with mono- or bi-layer cellulose molecular sheet thickness -- was synthesized through a combined chemical-mechanical process (TEMPO-mediated oxidation followed by intensive sonication), and this new material was named molecularly thin nanocellulose (MT nanocellulose).  The overarching objective of this study was to understand the formation and supramolecular structure of MT nanocellulose and contribute to the knowledge of native cellulose structure. The research involved four major bodies of study: preparation of MT nanocellulose, characterization of MT nanocellulose, modeling wood pulp-derived cellulose microfibril cross section structure, and a comparative life cycle assessment (LCA) of different nanocellulose fabrication approaches.  The results revealed that MT nanocellulose with mono- to bi-layer sheet thickness (~0.4-0.8 nm), three to six chain width (~2-5 nm), and hundreds of nanometers to several microns length, can be prepared through TEMPO-mediated oxidation followed by 5-240 min intensive sonication.  The thickness, width, and length of MT nanocellulose all decreased with extended sonication time and leveled off after 1 or 2 h sonication.  Crystallinity, hydrogen bonding, and glycosidic torsion angles were evaluated by XRD, FTIR, Raman, and NMR.  These experiments revealed systematic changes to structure with sonication treatments.  A microfibril "cross section triangle scheme" was developed for the microfibril supramolecular modeling process and a 24-chain hexagonal/elliptical hybrid model was proposed as the most credible representation of the supramolecular arrangement for wood pulp-derived cellulose I" microfibril.  Comparative LCA of the fabrication of nanocellulose indicated that nanocellulose presented a significant environmental burden markup on its precursor, kraft pulp, and the environmental hotspot was attributed to the mechanical disintegration process.  Yet, overall nanocellulose still presented a prominent environmental advantage over other nanomaterials like single-walled carbon nanotubes, due to its relative low energy consumption. Overall, this research developed a facile approach to produce a new type of nanocellulose, the MT nanocellulose, provided new insights about the supramolecular structure of cellulose microfibrils, and evaluated the environmental aspects of the fabrication process of nanocellulose. / Ph. D.

Nas últimas décadas observou-se tanto o crescimento das preocupações ambientais e de sustentabilidade. Neste contexto, surgiu o conceito de biorrefinaria. No Brasil, uma das principais lavouras agroindustriais é a produção de cana-de-açúcar. A indústria sucroalcooleira já atua como um modelo de biorrefinaria tendo a possibilidade de produção de açúcar de etanol e ainda de energia elétrica. Contudo, existe grande potencialidade de produtos de originários de biomassa vegetal. Alguns exemplos das potencialidades são: (i) a utilização dos açúcares da fração polissacarídica para produção de etanol; (ii) produção de polpa e papel; (iii) produção de nanomateriais entre outras. Assim, este trabalho se propõe a buscar e aplicar tecnologias e processos voltados a utilização da cana-de-açúcar para a obtenção de produtos variados. O primeiro processo utilizado é a separação das frações casca e miolo da cana-de-açúcar: na casca existe uma baixa quantidade de células de armazenamento de açúcar e uma maior proporção de fibras estruturais ademais, da epiderme extrai-se a cera; na fração miolo concentra-se a maior parte do caldo rico em sacarose, pela elevada quantidade de células de parênquima. Visando elevar a concentração de sacarídeos para a produção de etanol estudou-se a realização de um processo hidrotérmico usando o próprio suco da cana-de-açúcar para a extração de açúcares da fração de hemiceluloses. Observou-se que para a reação hidrotérmica em meio neutro na faixa de temperaturas estudada (110 a 130°C) cerca de 95% dos sacarídeos são conservados. Contudo, nestas condições reacionais a preservação de massa de hemiceluloses também se mantém nesta faixa, assim verificou-se que o uso de um catalizador ácido permitiria uma conservação de sacarídeos similar e aceleraria a reação de remoção de hemiceluloses. Usando processos similares aos usados na indústria de papel e celulose obteve-se dois materiais celulósicos das frações casca e miolo de cana-de-açúcar com características físico-mecânicas diferenciadas. Apesar do maior teor de células de parênquima no miolo original, observou-se que o papel desta fração apresentou resultados promissores com propriedades similares ao de papeis comerciais. A partir destas polpas, obteve-se dois materiais celulósicos nanofibrilados distintos, sendo o material da casca dúctil e o de miolo mais rígido (maior módulo de Young) e ao mesmo tempo mais frágil (menor alongamento para a ruptura). Verificou-se ainda que a partir dessas polpas celulósicas pode-se produzir nanocristais de celulose II usando um processo de hidrólise e solubilização com ácido sulfúrico seguido de reprecipitação. Desenvolveu-se o processo de produção de nanocristais de celulose I usando água subcrítica associado ou não a CO2. Este processo tem o potencial de substituir a atual produção de nanocristais de celulose visto que neste utiliza-se somente água (com ou sem CO2) para promover a hidrólise em oposição ao método clássico que usa elevadas concentrações de ácido sulfúrico permitindo uma economia financeira e produzindo menor volume de resíduos. / In the last decades environmental concerns and sustainability have grown. In this context, the biorefinery concept arose. In Brazil, one of the leading agro-industrial crops is the production of sugarcane. The sugar industry is already a model of a biorefinery because of the possibility of producing ethanol, sugar and even electricity. However, plant biomass still has a great potential to produce new materials and chemicals. Some of the capabilities are: (i) the use of the sugars from the polysaccharide fraction aiming the ethanol production; (ii) the production of pulp and paper; (iii) production of nanomaterials, among others. This work aims to seek and apply technologies and processes to obtain different products from sugarcane. The first used is the separation of the rind and core fractions of sugarcane: in the rind there is a low amount of sugar storage cells and a higher proportion of structural fibers, and also wax from the epidermis; the core fraction concentrates the majority of the sucrose rich broth as consequence of the high quantity of parenchyma cells. In order to increase the concentration of saccharides a hydrothermal process was studied using the own juice of sugar cane to extract sugars from the hemicellulose fraction. It was observed that for the hydrothermal reaction in neutral medium in the temperature range studied (110 to 130 °C) of about 95% saccharides are conserved. However, in these reaction conditions the hemicellulose preservation is also kept in this range, so it was found that the use of an acid catalyst allow similar saccharides recovery and accelerate the hemicellulose removal. Using similar procedures to those of the pulp and paper industry two cellulosic materials with differentiated physical and mechanical characteristics were obtained from the rind and core fractions of sugarcane. Although most parenchyma content in the original core material, it was observed that this fraction showed promising results with properties similar to commercial papers. From these pulps, two different nanofibrillated cellulosic materials were obtained, being the rind material a ductile material and the core a rigid (higher Young\'s modulus) and brittle (lower elongation at break) one. It was also found that from these pulps cellulose II nanocrystals can be produced using a process of hydrolysis and solubilization with sulfuric acid followed by a reprecipitation process. The production of cellulose I nanocrystals through processes using subcritical water with or without CO2 were developed. These processes have the potential to replace the current nanocrystals production since only water is used (with or without CO2) to promote the hydrolysis, compared to the traditional method, which uses high concentrations of sulfuric acid, thus enabling economical saves and producing less amount of wastes.

Submitted by Eunice Novais (enovais@uepg.br) on 2018-06-15T18:10:58Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Kerolin Ap Alves Gomes.pdf: 2922365 bytes, checksum: ccbcc929da0afe5876dd9273d11519e6 (MD5) / Made available in DSpace on 2018-06-15T18:10:58Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Kerolin Ap Alves Gomes.pdf: 2922365 bytes, checksum: ccbcc929da0afe5876dd9273d11519e6 (MD5) Previous issue date: 2018-01-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A utilização de materiais ambientalmente corretos, de fonte renovável, assim como a celulose, tem se apresentado como assunto de interesse para muitos pesquisadores. Neste trabalho os nanocristais de celulose (NCC) foram extraídos a partir da celulose microcristalina comercial (CMC) com posterior ajuste de pH e modificação superficial com o surfactante catiônico brometo de cetil trimetil amônio (CTAB), objetivando-se realizar a secagem dos NCC e posterior redispersão em água. Para tanto, foram estudadas as influências dos procedimentos de diálise, da faixa de pH, da modificação superficial e também da técnica de secagem sobre a estabilidade coloidal e também sobre a distribuição de tamanhos de partículas. Três técnicas de secagem foram estudadas: (1) secagem em estufa, (2) secagem por liofilização e (3) secagem por spray drying. Na secagem em estufa houve a formação de aglomerados indissolúveis impedindo a redispersão dos NCC, nesta técnica foi avaliado principalmente o efeito do ajuste de pH, observando-se que para condições ácidas de pH ocorre a degradação dos NCC. Na secagem por liofilização foi possível redispersar os NCC em água, porém não foi obtido um material seco estável, pois ocorreu a dessorção da água. Observou-se também que para adições maiores do contra-íon +, obtiveram-se melhores resultados de redispersão quanto à distribuição de tamanho de partículas. Na técnica de secagem por spray drying foi testada a influência do surfactante sobre a redispersão. A adsorção do surfactante catiônico à superfície dos NCC foi confirmada pela técnica de espectroscopia no infravermelho por transformada de Fourier (FTIR). Ficou demonstrado que com a adição de 1% de surfactante às suspensões de NCC é possível redispersá-las obtendo características muito próximas as das suspensões antes do processo de secagem, no entanto, observou-se perda da estabilidade coloidal para algumas amostras após a redispersão. As técnicas de microscopia eletrônica de varredura (MEV), difração de raios X (DRX), análise termogravimétrica (ATG) e análise reológica foram usadas para caracterizar o material obtido na secagem por spray drying, que foi determinada como a melhor técnica de secagem. A morfologia das partículas apresentou-se no formato esférico, com a formação de aglomerados. Foram obtidos elevados índices de cristalinidade para as amostras com adsorção do surfactante CTAB, porém com reduzida estabilidade térmica. A avaliação da viscosidade cinemática indicou um comportamento pseudoplástico para as suspensões do NCC e um aumento na viscosidade das amostras após a secagem e redispersão indicou a formação de aglomerados / The use of environmentally friendly materials from renewable sources, as well as cellulose, has been presented as a subject of interest to many researchers. In this work the cellulose nanocrystals (CNC) were extracted from commercial microcrystalline cellulose (CMC) with subsequent pH adjustment and surface modification with the cationic surfactant cetyl trimethyl ammonium bromide (CTAB), aiming to dry the CNC and rehydrate them in water. The influence of dialysis procedure, pH range, surface modification and drying technique on colloidal stability and particle size distribution were studied. Three drying techniques were studied: (1) oven drying, (2) drying by lyophilization and (3) spray drying. The oven drying process showed the formation of indissoluble agglomerates preventing the redispersion of CNC, in this technique the effect of the pH adjustment was evaluated, and it was observed that for acidic pH conditions the degradation of CNC occurs. On drying by lyophilization it was possible to redisperse the CNC in water, but it was not possible to obtain a stable dry material, as water desorption occurred. It was also observed that for larger additions of the counterion +, better particle size distribution results were obtained for the redispersed suspensions. The influence of the surfactant on redispersion was tested in the spray drying drying technique. The adsorption of the cationic surfactant to the surface of the CNC was confirmed by the Fourier transform infrared spectroscopy (FTIR) technique. It has been shown that with the addition of 1% surfactant to the CNC suspensions it is possible to redisperse them obtaining characteristics very close to those of the suspensions prior to the drying process, however, loss of colloidal stability has been observed for some samples after redispersion. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and rheological analysis were used to characterize the material obtained by spray drying, which was determined as the most suitable drying technique. The particles were presented with a spherical morphology and with the formation of agglomerates. High crystallinity indexes were obtained for samples with adsorption of CTAB surfactant, but with low thermal stability. The kinematic viscosity assessment indicated a pseudoplastic behavior for the CNC suspensions and an increase in the viscosity of the samples after drying and redispersion indicated the formation of agglomerates.

Organic electronics is the study of organic materials with electronic functionality and the applications of such materials. In the 1970s, the discovery that polymers can be made electrically conductive led to an explosion within this field which has continued to grow year by year. One of the attractive features of organic electronic materials is their inherent mechanical flexibility, which has led to the development of numerous flexible electronics technologies such as organic light emitting diodes and solar cells on flexible substrates. The possibility to produce electronics on flexible substrates like plastic or paper has also had a large impact on the field of printed, electronics where inks with electronic functionality are used for large area fabrication of electronic devices using classical printing methods, such as screen printing, inkjet printing and flexography. Recently, there has been a growing interest in the use of cellulose in organic and printed electronics, not only as a paper substrate but also as a component in composite materials where the cellulose provides mechanical strength and favorable 3D-microstructures. Nanofibrillated cellulose is composed of cellulose fibers with high aspect-ratio and diameters in the nanometer range. Due to its remarkable mechanical strength, large area-to-volume ratio, optical transparency and solution processability it has been widely used as a scaffold or binder for electronically active materials in applications such as batteries, supercapacitors and optoelectronics. The focus of this thesis is on flexible devices based on conductive polymers and can be divided into two parts: (1) Composite materials of nanofibrillated cellulose and the conductive polymer PEDOT:PSS and (2) patterning of vapor phase polymerized conductive polymers. In the first part, it is demonstrated how the combination of cellulose and conductive polymers can be used to make electronic materials of various form factors and functionality. Thick, freestanding and flexible “papers” are used to realize electrochemical devices such as transistors and supercapacitors while lightweight, porous and elastic aerogels are used for sensor applications. The second focus of the thesis is on a novel method of patterning conductive polymers produced by vapor phase polymerization using UV-light. This method is used to realize flexible electrochromic smart windows with high-resolution images and tunable optical contrast.

Almost all research on biorefinery concepts are based on chemical pulping processes and ways of utilising lignin, hemicelluloses and extractives as well as a part of the remaining cellulose for production of nano materials in order to create more valuable products than today. Within the Forest as a Resource (FORE) research program at FSCN we are utilising the whole chain of unit processes from forestry to final products as paper and board, where the pulping process research focus on high yield process as TMP and CTMP. As these process solutions are preserving or only slightly changing the properties of the original wood polymers and extractives, the idea is to find high value adding products designed by nature. From an economic perspective, the production of nanocellulose from a chemical pulp is quite expensive as the pulp has to be either enzymatically (e.g. mono-component endoglucanase) pre-treated or chemically oxidised using the TEMPO (2,2,6,6 - tetramethyl-piperidine-1-oxil) - mediated oxidation method in order to make it possible to disrupt the fibres by means of homogenisation. In high yield pulping processes such as in TMP and CTMP, the idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nano-ligno-cellulose (NLC). The integration of a NLC unit process in a high yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and board grades. The intention of this research work was that, by using this concept, a knowledge base can be created so that it becomes possible to develop a low-cost production method for its implementation. In order to study the potential of this concept, treatment of thermo-mechanical pulp (TMP) fines fractions were studied by means of homogenisation It seems possible to homogenise fine particles of thermo-mechanical pulp (1% w/v) to NLC. A correspond fines fraction from bleached kraft pulp (BKP) was tested as a reference at 0.5% w/v concentration. The objective presented in this work was to develop a methodology for producing mechanical pulp based NLC from fines fractions and to utilise this material as strength additives in paper and board grades. Laboratory sheets of CTMP and BKP, with addition of their respective NLC, were made in a Rapid Köthen sheet former. It was found that handsheets of pulp fibres blended with NLC improved the z-strength and other important mechanical properties for similar sheet densities. The characterisation of the particle size distribution of NLC is both important and challenging and the crill methodology developed at Innventia (former STFI) already during the 1980s was tested to see if it would be both fast and reliable enough. The crill measurement technique is based on the optical responses of a micro/nano particle suspension at two wavelengths of light; UV and IR. The crill value of TMP and CTMP based nano-ligno-cellulose were measured as a function of the homogenisation time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time.