Morphology templates of solution–based diblock copolymer (DBC) films with loading metal salts are widely applied in photocatalysts, photovoltaics, and sensors due to their adjustable characteristics based on surface (de–)wetting and microphase separation. The present work investigates the morphologies of drop–cast hybrid films based on poly(styrene)–b–poly(ethylene oxide) (PS–b–PEO) and the metal salts titanium isopropoxide (TTIP) and zinc acetate dehydrate (ZAD) in comparison to the pure DBC. By utilizing scanning electron microscopy, grazing–incidence small– and wide–angle X-ray scattering, and differential scanning calorimetry, we find that the resulting film morphologies depend not only on the presence of metal salts but also on solvent evaporation and crystalline formation. At 20 °C, additional TTIP and ZAD in the polymer template cause the morphology to change from packed globular structures to separated wormlike structures attributed to the changed polymer environment. Furthermore, additional tetrahydrofuran causes irregular structures at the precursor film part and the overlapped wormlike structures to transition into close–packed globular structures at the cap film parts of the pure DBC. In contrast, at 50 °C, the globular structures transit to fingerprint patterns due to the thermal behavior of the crystallizable PEO blocks, and the metal salt additives suppress crystalline structure formation in the PEO domains.

Cellulose is a natural polymer with great properties such as high optical transparency and mechanical strength, flexibility, and biodegradability. Hence, cellulose-based foils are suitable for the replacement of synthetic polymers as substrate materials in organic electronics. This article reports the fabrication of ultrathin, free-standing cellulose foils by spraying aqueous 2,2,6,6-tetramethylpiperidine-1-oxyl-nanocellulose (TEMPO) fibrils ink layer-by-layer on a hot substrate using a movable spray nozzle. The resulting foils are only 2 ± 1 µm in thickness with an average basis weight of 1.9 g m−2, which ranges in the same scale as the world's thinnest paper. The suitability of these ultra-thin nanocellulose foils as a sustainable substrate material for organic electronic applications is demonstrated by testing the foils resistance against organic solvents. Furthermore, silver nanowires (AgNWs) and the blend poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) are integrated into the foils, and the foils are molded into 3D paper structures in order to create conductive, paper-based building blocks for organic electronics.

The colloidal layer formation on porous materials is a crucial step for printing and applying functional coatings, which can be used to fabricate anticounterfeiting paper. The deposition of colloidal layers and subsequent thermal treatment allows for modifying the hydrophilicity of the surface of a material. In the present work, wood-based colloidal inks are applied by spray deposition on spray-deposited porous cellulose nanofibrils (CNF) films. The surface modification by thermal annealing of the fabricated colloid-cellulose hybrid thin films is investigated in terms of layering and hydrophobicity. The polymer colloids in the inks are core-shell nanoparticles with different sizes and glass transition temperatures (T-g), thus enabling different and low thermal treatment temperatures. The ratio between the core polymers, poly(sobrerol methacrylate) (PSobMA), and poly(-butyl methacrylate) (PBMA) determines the T-g and hence allows for tailoring of the T-g. The layer formation of the colloidal inks on the porous CNF layer depends on the imbibition properties of the CNF layer which is determined by their morphology. The water adhesion of the CNF layer decreases due to the deposition of the colloids and thermal treatment except for the colloids with a size smaller than the void size of the porous CNF film. In this case, the colloids are imbibed into the CNF layer when T-g of the colloids is reached and the polymer chains transit in a mobile phase. Tailored aggregate and nanoscale-embedded hybrid structures are achieved depending on the colloid properties. The imbibition of these colloids into the porous CNF films is verified with grazing incidence small-angle X-ray scattering. This study shows a route for tuning the nanoscale structure and macroscopic physicochemical properties useful for anticounterfeiting paper.

The present thesis explores the utilization of spray coating for the sustainable fabrication of cellulose-based organic electronics in the framework of four different studies. The scope of this work is to contribute to the ongoing green transformation of our society in the context of industrial processing, responsible production, and clean energy. In this regard, spray coating was applied as a low-cost, fast, and industrially relevant technique for both the production as well as the quality enhancement of functional organic polymer films. In addition to that, wood-based nanocellulose, a non-toxic and biodegradable polymer, was used to replace synthetic polymers as transparent, flexible matrix- and substrate material, and as dispersing agent for the fabrication of highly conductive electrodes. Finally, spray solvents were evaluated regarding their sustainability, industrial fitness, and thus suitability for the large-scale production of organic electronics. In the course of this, various kinds of functional, hybrid organic films and foils were fabricated. Their properties were correlated with their respective structure and morphology, with a special focus on surface-sensitive analysis techniques, namely grazing incidence X-ray scattering, atomic force microscopy, scanning electron microscopy, and sheet resistance measurements.

Den här avhandlingen undersöker användningen av spraybeläggning för en hållbar produktion av cellulosabaserade, organiska elektronik inom ramen för fyra olika studier. Syftet med detta arbete är att bidra till den pågående gröna omvandlingen av vårt samhälle inom ramen för industriell bearbetning, ansvarsfull produktion och ren energi.I avhandlingen studeras spraybeläggning som en billig, snabb och industriellt relevant teknik för både produktion och kvalitetsförbättring av funktionella, organiska polymerfilmer. Utöver detta undersöks träbaserad nanocellulosa, en giftfri och biologiskt nedbrytbar polymer, för att ersätta syntetiska polymerer som genomskinligt, flexibelt matris- och substratmaterial samt som dispergeringsmedel vid tillverkning av högkonduktiva elektroder. Slutligen utvärderas spraylösningsmedel utifrån hållbarhet, industriell användbarhet och därmed lämplighet för storskalig produktion av organisk elektronik. Under arbetets gång har olika typer av funktionella, hybrida organiska filmer och folier tillverkats. Deras egenskaper kan kopplas till deras struktur och morfologi, med hjälp av ytkänsliga analysmetoder, nämligen röntgenspridning vid låg infallsvinkel, atomkraftsmikroskopi och svepelektronmikroskopi.

A series of different technical hardwood lignin-based resins have been successfully synthesized, characterized, and utilised to produce thiol-ene thermoset polymers. Firstly, technical lignin was fractionated and allylated, whereafter it was crosslinked with a trifunctional thiol. Structural and morphological characteristics of the lignin fractions were studied by 1H NMR, 31P NMR, SEC, FTIR, DSC, TGA, and WAXS. The hardwood lignin fractions have a high content of C5-substituted OH groups. The WAXS studies on lignin fractions revealed the presence of two π-π stacking conformations, sandwiched (4.08–4.25 Å) and T-shaped (6.52–6.91 Å). The presence of lignin superstructures with distances/sizes between 10.5 and 12.8 Å was also identified. The curing reaction of the thermosets was investigated by RT-FTIR. Almost all thermosets (excepting one fraction) reached 95% of the thiol conversion in less than 17 h, revealing the enhanced reactivity of the allylated hardwood lignin samples.

The mechanical properties of the thermosets were investigated by DMA. The curing performance, as well as the final thermoset properties, have been correlated to variations in chemical composition and morphological differences of lignin fractions. The described results clearly demonstrate that technical hardwood lignins can be utilized for these applications, but also that significant differences compared to softwood lignins have to be considered for material design.

In times of climate change and resource scarcity, researchers are aiming to find sustainable alternatives to synthetic polymers for the fabrication of biodegradable, eco-friendly, and, at the same time, high-performance materials. Nanocomposites have the ability to combine several favorable properties of different materials in a single device. Here, we evaluate the suitability of two kinds of inks containing silver nanowires for the fast, facile, and industrial-relevant fabrication of two different types of cellulose-based silver nanowire electrodes via layer-by-layer spray deposition only. The Type I electrode has a layered structure, which is composed of a network of silver nanowires sprayed on top of a cellulose nanofibrils layer, while the Type II electrode consists of a homogeneous mixture of silver nanowires and cellulose nanofibrils. A correlation between the surface structure, conductivity, and transparency of both types of electrodes is established. We use the Haacke figure of merit for transparent electrode materials to demonstrate the favorable influence of cellulose nanofibrils in the spray ink by identifying Type II as the electrode with the lowest sheet resistance (minimum 5 ± 0.04 Ω/sq), while at the same time having a lower surface roughness and shorter fabrication time than Type I. Finally, we prove the mechanical stability of the Type II electrode by bending tests and its long-time stability under ambient conditions. The results demonstrate that the mixed spray ink of silver nanowires and cellulose nanofibrils is perfectly suitable for the fast fabrication of highly conductive organic nanoelectronics on an industrial scale.

Titanium dioxide (TiO2) is an excellent candidate material for semiconductor metal oxide-based substrates for surface-enhanced Raman scattering (SERS). Biotemplated fabrication of TiO2 thin films with a 3D network is a promising route for effectively transferring the morphology and ordering of the template into the TiO2 layer. The control over the crystallinity of TiO2 remains a challenge due to the low thermal stability of biopolymers. Here is reported a novel strategy of the cellulose nanofibril (CNF)-directed assembly of TiO2/CNF thin films with tailored morphology and crystallinity as SERS substrates. Polymorphous TiO2/CNF thin films with well-defined morphology are obtained by combining atomic layer deposition and thermal annealing. A high enhancement factor of 1.79 × 106 in terms of semiconductor metal oxide nanomaterial (SMON)-based SERS substrates is obtained from the annealed TiO2/CNF thin films with a TiO2 layer thickness of 10 nm fabricated on indium tin oxide (ITO), when probed by 4-mercaptobenzoic acid molecules. Common SERS probes down to 10 nm can be detected on these TiO2/CNF substrates, indicating superior sensitivity of TiO2/CNF thin films among SMON SERS substrates. This improvement in SERS sensitivity is realized through a cooperative modulation of the template morphology of the CNF network and the crystalline state of TiO2.

Biomimetic actuators are promising candidates for smart soft robotics. The applications of state-of-the-art actuators require the combination of programmable stimuli-responsiveness, excellent robustness, and efficient self-healing ability in a wide-range of working conditions. However, these properties may be mutually exclusive. Inspired by biological tissues, two kinds of polyelectrolytes including polyvinyl alcohol (PVA) and polystyrene sulfonate (PSS) are exploited as the fillers of cellulose nanofibrils (CNFs) for the fabrication of the CNF/PVA/PSS (CAS) film via the assembly of the physically-crosslinked network through multiple H-bonding and electrostatic interactions. Achieved by a casting-evaporation strategy, internal stress is stored within the polymer matrix and transforms into reversible anisotropic bending deformations in response to a humidity gradient. The speed, direction, and pitch of the bending can be programmed by tailoring the internal stresses and geometry of the samples. Moreover, the H-bonded network also contributes to the effective energy dissipation toward high toughness during tensile stretching, as well as self-healing ability during moisture saturation of the CAS films. This enables the fabrication of a humidity-sensitive flower-shaped actuator and self-healable packaging paper. This study presents a biomimetic strategy for the fabrication of multi-functional soft robotics, which holds great promise for applications in the fields of biosensors and smart packaging. 

Iron-Cobalt (FeCo) columnar, multilayered structure is prepared by depositing several thin FeCo layers by varying the angle between the surface normal and the evaporation direction as 0 (normal) and 60(oblique), alternatively. In situ X-ray scattering and magneto-optical Kerr effect (MOKE) measurements established the evolution of magnetic properties with that of the morphology and structure of the multilayer. The strong shape anisotropy and compressive stress of nanocolumns in alternative FeCo layers resulted in a well-defined uniaxial magnetic anisotropy (UMA) with the easy axis of magnetization along the projection of the tilted nanocolumns in the film plane. The stress in the film provides minimization of magnetoelastic energy along the in-plane column direction, which couples with the columnar shape anisotropy energies and results in the preferential orientation of the magnetic easy axis along the oblique angle deposition direction in the film plane. Drastic reduction in the in-plane UMA after annealing at 450 C is attributed to the merging of columns and removal of stresses after heat treatment. The present study opens a new pathway to produce magnetically anisotropic multilayer structures using single material and thus may have prominent implications for future technological devices.