With the increasing global demand for net-zero carbon emissions, actions to address climate change have gained momentum among policymakers and the public. The urgent need for a sustainable economy is underscored by the mounting waste crisis in landfills and oceans. However, the proliferation of distributed electronic devices poses a significant challenge due to the resulting electronic waste. To combat this issue, the development of sustainable and environmentally friendly materials for these devices is imperative. Cellulose, an abundant and CO2-neutral substance with a long history of diverse applications, holds great potential. By integrating electrically interactive components with cellulosic materials, innovative biobased composites have been created, enabling the fabrication of bulk electroactive paper and the establishment of new, potentially more sustainable manufacturing processes for electronic devices. This review explores recent advances in bulk electroactive paper, including the fundamental interactions between its constituents, manufacturing techniques, and large-scale applications in the field of electronics. Furthermore, it addresses the importance and challenges of scaling up production of electroactive paper, highlighting the need for further research and development.

Paper is the largest renewable industrial substrate produced for various applications and can be recycled by disintegrating the fibers and reforming the paper. Paper and its fiber constituents lack functions such as electrical conductivity and papermaking itself has not been used for producing electronic devices. In this work, we show a potential industrially viable route for introducing cationic charges on the cellulose fibers and subsequently show how the adsorption of negatively charged ionically and electrically conductive materials onto these fibers from aqueous media can be applied at time scales relevant to industrial papermaking. This results in electroactive fibers, that can subsequently be used to prepare electroactive papers using standard papermaking procedures. Since fibers in the paper can selectively be coated with different active materials, various functions can be added into the paper. To demonstrate applications, we prepared electroactive papers using fibers with adsorbed carbon nanotubes (CNTs) and conducting polymers. We achieved conductivity of 21 S/m with only 1wt% CNT. We also prepared papers with CNTs and black phosphorus, used as paper-based lithium, and sodium ion battery (free-standing) anodes. They delivered a specific capacity of 642 mA h g⁻¹ at 100 mA g⁻¹ after 3500 cycles with 99.5% columbic efficiency. Furthermore, we recycled the papers, and as the disintegration of the fibers did not lead to removal of the ionic or electroactive materials from the fiber surface, the recycled papers showed similar electrical and mechanical properties to the original papers. This opens the path for recyclable paper-based electronics.

There are many bioelectronic applications where the additive manufacturing of conductive polymers may be of use. This method is cheap, versatile and allows fine control over the design of wearable electronic devices. Nanocellulose has been widely used as a rheology modifier in bio-based inks that are used to print electrical components and devices. However, the preparation of nanocellulose is energy and time consuming. In this work an easy-to-prepare, 3D-printable, conductive bio-ink; based on modified cellulose fibers and poly(3,4-ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT:PSS), is presented. The ink shows excellent printability, the printed samples are wet stable and show excellent electrical and electrochemical performance. The printed structures have a conductivity of 30 S/cm, high tensile strains (>40%), and specific capacitances of 211 F/g; even though the PEDOT:PSS only accounts for 40 wt% of the total ink composition. Scanning electron microscopy (SEM), wide-angle X-ray scattering (WAXS), and Raman spectroscopy data show that the modified cellulose fibers induce conformational changes and phase separation in PEDOT:PSS. It is also demonstrated that wearable supercapacitors and biopotential-monitoring devices can be prepared using this ink.

Nanoscale infrared (IR) spectroscopy and microscopy, enabling the acquisition of IR spectra and images with a lateral resolution of 20 nm, is employed to chemically characterize individual cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) to elucidate if the CNCs and CNFs consist of alternating crystalline and amorphous domains along the CNF/CNC. The high lateral resolution enables studies of the nanoscale morphology at different domains of the CNFs/CNCs: flat segments, kinks, twisted areas, and end points. The types of nano-cellulose investigated are CNFs from tunicate, CNCs from cotton, and anionic and cationic wood-derived CNFs. All nano-FTIR spectra acquired from the different samples and different domains of the individual nanocellulose particles resemble a spectrum of crystalline cellulose, suggesting that the non-crystalline cellulose signal observed in macroscopic measurements of nanocellulose most likely originate from cellulose chains present at the surface of the nanocellulose particles.

The need for achieving sustainable technologies has encouraged research on renewable and biodegradable materials for novel products that are clean, green, and environmentally friendly. Nanocellulose (NC) has many attractive properties such as high mechanical strength and flexibility, large specific surface area, in addition to possessing good wet stability and resistance to tough chemical environments. NC has also been shown to easily integrate with other materials to form composites. By combining it with conductive and electroactive materials, many of the advantageous properties of NC can be transferred to the resulting composites. Conductive polymers, in particular poly(3,4-ethylenedioxythiophene:poly(styrene sulfonate) (PEDOT:PSS), have been successfully combined with cellulose derivatives where suspensions of NC particles and colloids of PEDOT:PSS are made to interact at a molecular level. Alternatively, different polymerization techniques have been used to coat the cellulose fibrils. When processed in liquid form, the resulting mixture can be used as a conductive ink. This review outlines the preparation of NC/PEDOT:PSS composites and their fabrication in the form of electronic nanopapers, filaments, and conductive aerogels. We also discuss the molecular interaction between NC and PEDOT:PSS and the factors that affect the bonding properties. Finally, we address their potential applications in energy storage and harvesting, sensors, actuators, and bioelectronics. 

Modern demand for consumer electronics is fueling the generation of 'E-waste.' Furthermore, theraw materials and manufacturing methods used in the fabrication of electronics are not sustainable.There is therefore the need to develop renewable and sustainable raw materials for electronicdevices that do not sacrifice performance; as well as a requirement to develop novel, scalable,sustainable electronic device fabrication methods that use these green electronic materials. To thisend, bio-based materials are an environment-friendly alternative to non-renewable materials; andprinted electronics could replace traditional manufacturing methods. Cellulose, one of the mostabundant biopolymers on Earth, exhibits an interesting hierarchical structure. Due to extensiveresearch over the years, there are a wide variety of established chemical modifications for cellulose,which can be harnessed to prepare high-performance electronic components. The hierarchicalstructure of cellulose is crucial in defining its material properties. In cellulose rich fibers, highmolecular mass glucan polymers are commonly found in the form of cellulose nanofibrils (CNFs);these can be liberated and, once so, are capable of self-assembling into a wide variety of structures.Since cellulose is electrically insulating, it needs to be made into composites with conductivematerials to form electrically conductive materials.This thesis investigates the interaction between cellulose and the conductive polymer PEDOT:PSS(poly(3,4-ethylenedioxythiophene) : polystyrene sulfonate), and demonstrates how a fundamentalunderstanding of the interactions between the two can be used to guide the chemical modificationof cellulose for the large scale production of sustainable electronics. First, the PEDOT:PSS structurewas studied using molecular dynamics (MD) simulations and experimental methods. Secondly, theinteraction between cellulose and PEDOT:PSS was studied, and factors affecting this interactionwere identified. This knowledge was then applied to propose a molecular interaction mechanismbetween these materials. Nanocellulose, especially cellulose nanofibrils (CNFs), have been integralto the development of bio-based conductive composites. However, the nanofibrillation process isexpensive and energy-intensive. In addition, PEDOT:PSS is an expensive polymer. Therefore, inthis work, chemically modified fibers were used to improve the interaction between cellulose andPEDOT:PSS; and prepare fiber-based bioelectronics and energy storage devices. The large-scaleproduction of papers capable of energy storage has also been demonstrated using chemicallymodifiedfibers, the factors affecting the processing of these materials have been identifiedthroughout.

En enorm efterfrågan på hemelektronik skapar ett stort "e-avfalls” problem i dagenssamhälle. De råvaror som idag används för att tillverka elektronik har ett högtkoldioxidavtryck, och traditionella tillverkningsmetoder för elektronik är dessutomenergikrävande. Därför finns det en stort behov av högpresterande, hållbara, billiga,förnyelsebara råvaror för elektroniska komponenter. Dessutom behövs nya, hållbarabearbetningsmetoder för att producera elektroniska komponenter med lägre mängderinbyggd energi. I detta avseende är biobaserade material ett miljövänligt alternativ till ickeförnybaramaterial och tryckt elektronik skulle kunna användas för att ersätta traditionellatillverkningsmetoder. Cellulosa är en mycket vanligt förekommande biopolymer i mångaväxter och i vissa djur och det finns många rationella metoder för att utvinna denna polymeroch polymeren är därför en mycket intressant råvara för framtida produkter. Denhögmolekylära glukanmolekylen organiseras i i de flesta fallen i cellulosa nanofibriller (CNF)som sedan anordnas i en hierarkisk struktur i makroskopiska fibrer. Modern forskning harockså visat att de frilagda fibrillerna kan självorganiseras i skräddarsydda nano-strukturersom kan vara mycket intressanta för att tillverka högpresterande elektroniska komponenter.Med hjälp av all den forskning som genomförts för cellulosamaterial genom åren finns detockså tillgång till en fantastisk verktygslåda för att kemiskt modifiera cellulosa för att passa iolika tillämpningar. Eftersom cellulosa är elektriskt isolerande är det nödvändigt attkombinera cellulosa med ett ledande material för att skapa skräddarsydda komponenter medgod elektrisk ledningsförmåga.Arbetet i denna avhandling har fokuserats på studera växelverkan mellan cellulosa och denledande polymer PEDOT:PSS, och för att klarlägga hur denna grundläggande förståelse kanutnyttjas för att identifiera nödvändiga kemiska modifieringar på cellulosan för att överföraresultaten till storskalig produktion av hållbar elektronik. Initialt studerades den molekyläraoch övermolekylära strukturen hos PEDOT:PSS komplex med en kombination avmolekylärdynamiska (MD) simuleringar och experimentella undersökningar. För det andrastuderades växelverkan mellan cellulosa och PEDOT:PSS, och det visade sig möjligt attidentifiera de faktorer som kontrollerar denna växelverkan. Dessa kunskaper användes sedanför att molekylärt förklara hur dessa material fundamentalt växelverkar med varandra.Nanocellulosa, särskilt cellulosa nanofibriller (CNF) har varit en del av biobaserade ledandekompositer. Nanofibrilleringsprocessen är dock kostnads- och energikrävande. Dessutom ärPEDOT:PSS en dyr polymer. Därför användes i detta arbete kemiskt modifierade fibrer föratt förbättra interaktionen mellan cellulosa och PEDOT:PSS (för att minska kostnaderna),och för att förbereda fiberbaserad bioelektronik och energilagringsenheter. Storskaligproduktion av energilagringspapper demonstrerades också med kemiskt modifierade fibreroch faktorer som påverkar bearbetningen av dessa material identifierades.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a conducting polymer frequently used with cellulose, to develop advanced electronic materials. To understand the fundamental interactions between cellulose and PEDOT:PSS, a quartz crystal microbalance with dissipation (QCM-D) was used to study the adsorption of PEDOT:PSS onto model films of cellulose-nanofibrils (CNFs) and regenerated cellulose. The results show that PEDOT:PSS adsorbs spontaneously onto anionically charged cellulose wherein the adsorbed amount can be tuned by altering solution parameters such as pH, ionic strength and counterion to the charges on the CNF. Temperature-dependent QCM-D studies indicate that an entropy gain is the driving force for adsorption, as the adsorbed amount of PEDOT:PSS increased with increasing temperature. Colloidal probe AFM, in accordance with QCM-D results, also showed an increased adhesion between cellulose and PEDOT:PSS at low pH. AFM images show bead-like PEDOT:PSS particles on CNF surfaces, while no such organization was observed on the regenerated cellulose surfaces. This work provides insight into the interaction of PEDOT:PSS/cellulose that will aid in the design of sustainable electronic devices.

PEDOT:PSS is the most widely used conducting polymer in organic and printed electronics. PEDOT:PSS films have been extensively studied to understand the morphology, ionic and electronic conductivity of the polymer. However, the polymer dispersion, which is used to cast or spin coat the films, is not well characterized and not well understood theoretically. Here, we study in detail the particle morphology, size, charge density and zeta potential (z-potential) by coarse-grained MD simulations and dynamic light scattering (DLS) measurements, for different pH levels and ionic strengths. The PEDOT:PSS particles were found to be 12 nm–19 nm in diameter and had a z-potential of −30 mV to −50 mV when pH was changed from 1.7 to 9, at an added NaCl concentration of 1 mM, as measured by DLS. These values changed significantly with changing pH and ionic strength of the solution. The charge density of PEDOT:PSS particles was also found to be dependent on pH and ionic strength. Besides, the distribution of different ions (PSS−, PEDOT+, Na+, Cl−) present in the solution is simulated to understand the particle morphology and molecular origin of z-potential in PEDOT:PSS dispersion. The trend in change of particle size, charge density and z- potential with changing pH and ionic strength are in good agreement between the simulations and experiments. Our results show that the molecular model developed in this work represents very well the PEDOT:PSS nano-particles in aqueous dispersion. With this study, we hope to provide new insight and an in-depth understanding of the morphology and z-potential evolution in PEDOT:PSS dispersion.