Fossil-based polymers dominate the packaging industry thanks to their performance and low cost. However, their negative impact on the biosphere demands a paradigm shift in the industry. Nature may provide an alternative in the form of suberin. Suberin is an amorphous polyester present in plants, where it contributes to controlling the water and gas exchange with the environment. The bark is rich in suberin, and it represents a large byproduct of the forestry industry; hence, it is a potential source of renewable monomers for the synthesis of packaging materials. In this study, we demonstrated that unrefined suberin monomers, extracted from birch bark, could be exploited to synthesize a cross-linked polyester film through a standard melt polycondensation and compression molding process. The polyester film resulted in being translucent while blocking UV radiation and having an elastomer-like behavior. The average measured water vapor transmission rate of 2660 g mu m day-1 m-2 was comparable to other polyesters, such as polylactide (1500-2000 g mu m day-1 m-2) and polycaprolactone (2653 g mu m day-1 m-2) at 23 +/- 2 degrees C, with an imposed gradient of 0-50% relative humidity. Finally, the thermal gravimetric analysis showed the absence of any unreacted suberin monomers, and although specific migration tests are required, these suberin-reconstructed polyester films are potential candidates for packaging applications.

Plant cells represent smart cargo carriers with great socioeconomic potential in oral drug delivery applications. The two exterior barriers, featuring a rigid cell wall and a dense plasma membrane, are unique with complementary structural, mechanical, and chemical properties. Current strategies for producing therapeutic drugs within plant cells for oral delivery are efficient, but largely limited to recombinant pharmaceutical proteins, and involve complex genetic modification of plants. To address this, we engineer plant cell-inspired delivery systems with cellulose nanofiber-based shells and lipid layers through a bottom-up assembly strategy, which offers greater flexibility to encapsulate nonprotein compounds and nanoparticles. Notably, the layered shell structure resists degradation in acidic environments, and two barriers respond differently to external stimuli in simulated gastrointestinal medium, resulting in size-dependent dual-triggered release mechanisms. The cytocompatibility was shown by incubation with Caco-2 cells. Our results open avenues for developing next generation of bioinspired oral delivery systems for multisite-specific gastrointestinal release in a low-cost and sustainable manner.

In nature, colors can originate from pigments or structural effects, with the latter producing brilliant hues through the interference of light with nanoscale structures. This study describes a feasible strategy to achieve structurally colored films based on acetylated lignin nanoparticles. Lignin nanoparticles were prepared by using membrane emulsification and subsequently self-assembled into multilayered films on silicon substrates through an evaporative process. These films exhibit vivid structural colors resulting from thin-film interference, with hues that vary with film thickness. Spectroscopic reflectance measurements and structural analysis reveal a wide range of colors spanning across the visible spectrum. The observed colors are ascribed to interference effects and could be modeled using the transfer matrix method. Furthermore, we demonstrate that increasing relative humidity causes clear color shifts associated with reflectance peak position changes.

Structural coloration offers a sustainable and non-fading alternative to conventional pigment- and dye-based colorants. In this study, we present a scalable strategy for generating vivid, tunable structural colors using ultrathin films of industrial kraft lignin. By employing solvent fractionation to isolate a methanol-soluble lignin fraction, followed by spin-coating onto silicon substrates, we achieve highly uniform films with controllable thickness. The observed colors originate from thin-film interference and span the entire visible spectrum by adjusting lignin concentration and spin speed. Spectroscopic ellipsometry and transfer matrix modeling confirm that the interference is modulated by the film thickness. The lignin films exhibit robust mechanical properties, limited angular color shift, and fast, reversible optical response to humidity changes, enabling real-time environmental sensing. This approach circumvents the need for nanoparticle synthesis or self-assembly and highlights the potential of lignin, a widely available and underutilized biopolymer, as a functional photonic material for sustainable optical coatings and colorimetric sensors.

Fossil-based packaging materials pose significant environmental challenges due to their persistence and carbon footprint, resulting in pollution and long-term climate change. Here we develop bioplastic packaging alternatives (films and trays) from protein-rich microbial biomass with glycerol as the plasticizer. The microbial biomass demonstrated excellent film-forming properties through compression molding, and the final materials exhibited good mechanical properties and excellent gas barrier properties - an average oxygen permeability coefficient of 0.33 cm3 mm m-2 day-1 atm-1 at 50

The majority of plastics used today are produced from nonrenewable resources, and, depending on the end-of-life management, they may end up in landfills or in nature, giving rise to microplastic pollution. A potential way of minimizing this is to use proteins, preferentially recovered from organic waste and residues, to make plastics. In line with this, we explored here the potential of protein-based bioplastics sourced from single-cell protein (SCP). Films of glycerol-plasticized SCPs (grown by recovering carbon from cheese whey and nitrogen from anaerobic digestate) were produced by compression molding. Electron microscopy revealed a structure of intact cells and the presence of cracks/voids, and the mechanical properties indicated a rather poor cohesion between the cells, despite the high-temperature treatment in the pressing stage. The resulting structure yielded a material that could absorb a sizable amount of both nonpolar (rapid capillary uptake) and polar liquids. The anaerobic biodegradation of the SCP films demonstrated that full biodegradability (100%) and high specific biomethane productions (471 +/- 8 mL/gram of volatile solids) could be attained within operating conditions that are typical of anaerobic digestion processes in the treatment of food waste. Overall, this study highlights the potential and also the challenge of using SCP as an alternative bioplastic material in food packaging and edible coatings.

The amount of disposable nonwovens used today for different purposes have an impact on the plastic waste streams which is built up from several single-use products. A particular problem comes from nonwoven products with "hidden" plastic (such as cellulose mixed with synthetic fibers and/or plastic binders) where the consumers cannot see or expect plastic. We have here developed a sustainable binder based on natural components; wheat gluten (WG) and a polyelectrolyte complex (PEC) made from chitosan, carboxymethyl cellulose and citric acid which can be used with cellulosic fibers, creating a fully biobased nonwoven product. The binder formed a stable dispersion that improved the mechanical properties of a model nonwoven. With WG added, both the dry and the wet strength of the impregnated nonwoven increased. In dry-state, PEC increased the tensile index with >30 % (from 22.5 to 30 Nm/g), and with WG, with 60 % (to 36 Nm/g). The corresponding increase in the wet strength was 250 % (from 8 to 28 Nm/g) and 300 % (to 32 Nm/g). The increased strength was explained as an enrichment of covalent bonds (ester and amide bonds) established during curing at 170 °C, confirmed by DNP NMR and infrared spectroscopy.

Petrochemical-based plastics are prevalent in the packaging industry. However, given their detrimental impact on the environment, alternatives for future packaging materials are necessary. In this work, the inspiration for creating new types of packaging materials was taken from plant cuticle structures in nature. Potential eco-friendly solutions could be derived from plants. We fabricated cuticle-like materials using molecules found in natural cutins. A cross-linked material was developed through the melt polycondensation of hexadecanedioic acid and glycerol and with the addition of hydroxy-hexadecanoic acid, a noncross-linked terpolyester was obtained. Both compression molding and casting techniques resulted in flexible and transparent/translucent films. Both polyester films showed very low direct UV transmittance, but noticeable total UV transmittance. These semicrystalline materials exhibited water vapor transmission rates that were comparable or superior to other polyesters, such as polylactide and polycaprolactone. An intriguing characteristic was the rough surface exhibited by the copolyester following compression molding, which closely resembled the wax layer structure seen in many natural peels.

Exploring the possibility of using various silsesquioxane precursors such as (3-aminopropyl) triethoxysilane (APTES), methyltrimethoxysilane (MTMS), and tetraethyl orthosilicate (TEOS) to produce silica-bacterial cellulose nanofibre (bCNF) aerogel.

Hydroxypropyl cellulose (HPC) is known for its ability to form cholesteric liquid crystalline phases displaying vivid structural colors. However, these vibrant colors tend to fade over time when the material dries. This issue is a major bottleneck to finding practical applications for these materials. Here this problem is overcome by producing free-standing, millimeter-sized HPC structurally colored beads with spatiotemporal color retention, facilitated by a glutaraldehyde crosslinker. By leveraging the well-known chemically induced stabilization of cholesteric liquid crystalline phases, stable structural colors are achieved for at least three weeks. The presence of glutaraldehyde significantly increases the mechanical stiffness, with Young's modulus rising from 0.3 +/- 0.1 GPa to 1.8 +/- 0.2 GPa. This integrated approach of creating free-standing photonic HPC beads offers a strategy for developing robust and durable photonic HPC materials with enhanced stability, advancing photonic material applications with spatiotemporal color stability.

Purpose To study the effect of cellulose nanofiber (CNF)-shelled perfluoropentane (PFP) droplets on the cell viability of 4T1 breast cancer cells with or without the addition of non-encapsulated paclitaxel. Methods The CNF-shelled PFP droplets were produced by mixing a CNF suspension and PFP using a homogenizer. The volume size distribution and concentration of CNF-shelled PFP droplets were estimated from images taken with an optical microscope and analyzed using Fiji software and an in-house Matlab script. The thermal stability was qualitatively assessed by comparing the size distribution and concentration of CNF-shelled PFP droplets at room temperature (~22°) and 37°C. The cell viability of 4T1 cells was measured using a 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, a hemolysis assay was performed to assess blood compatibility of CNF-shelled PFP droplets. Results The droplet diameter and concentration of CNF-shelled PFP droplets decreased after 48 hours at both room temperature and 37°C. In addition, the decrease in concentration was more significant at 37°C, from 3.50 ± 0.64×106 droplets/mL to 1.94 ± 0.10×106 droplets/mL, than at room temperature, from 3.65 ± 0.29×106 droplets/mL to 2.56 ± 0.22×106 droplets/mL. The 4T1 cell viability decreased with increased exposure time and concentration of paclitaxel, but it was not affected by the presence of CNF-shelled PFP droplets. No hemolysis was observed at any concentration of CNF-shelled PFP droplets. Conclusion CNF-shelled PFP droplets have the potential to be applied as drug carriers in ultrasound-mediated therapy.

Using biobased polyelectrolytes to emulsify natural fatty molecules is one possible key technology to create sustainable materials. The emulsions can be used in papermaking instead of synthetic hydrophobizing agents or in nonwoven manufacturing to create strong, hydrophobic textile-like materials. This article investigates a novel emulsification system based on a polyelectrolyte complex between chitosan dissolved in citric acid and carboxymethyl cellulose together with sunflower (Helianthus annuus) oil. Viscose nonwoven treated with the emulsion had a contact angle of over 120 degrees. Tensile tests showed that the produced paper and nonwoven materials achieved high dry and, especially, high wet strength. Infrared spectroscopy illuminated the impact of heat curing the binder, and electron microscopy showed that the oil droplets from the emulsion were spread across the fibre surface. The results from this study enable sustainable nonwovens to be applied in areas where high dry and wet strength and water repellence are required; this includes outdoor applications, including agricultural mulch films, where nonwoven is used frequently and a sustainable approach is urgently needed to reduce the accumulation of plastics in the environment.

Shape-anisotropic building blocks are vital in the creation of hierarchical materials in nature, as it enables directional alignment, property anisotropy and overall functionality improvement in biological materials. Likewise, the performance of carbonized superstructures could potentially be more precisely designed by using anisotropic building blocks. Lignin represents an important and sustainable alternative in the production of carbonized materials, which is due to its abundance and high carbon content (similar to 60%). However, to expand its utility, for producing carbonized shape-anisotropic materials, adequate synthesis and pyrolysis-protocols are essential. Here, a fractionated and acetylated Kraft lignin was used to successfully self-assemble shape-anisotropic microcapsules. Then a carbonization procedure (slow heating at 0.6 C min(-1)), that retained the original shape-anisotropy after carbonization, was developed. The formation mechanism was discussed as a function of the heating rate. The overall strategy was template-free and the attained shape-anisotropies were well-defined and narrow in size distribution. This is a scalable route for achieving shape-anisotropic carbonized building blocks from lignin.

This work describes an emulsification-solvent-evaporation method for the preparation of liquid-filled capsules made from cellulose acetate. Two different emulsification techniques were applied: bulk emulsification by high-shear mixing, and droplet generation using microfluidics. The bulk emulsification method resulted in the formation of oil-in-water emulsions composed of an organic mixture of isooctane and cellulose acetate in methyl acetate, and an aqueous phase of high-molecular-weight polyvinyl alcohol (PVA). Upon the solvent evaporation, the emulsion droplets evolved into isooctane-filled cellulose acetate capsules. In contrast, microfluidics led to the formation of monodisperse droplets composed of the aqueous PVA solution dispersed in the organic phase. Upon the solvent evaporation, the emulsion droplets evolved into water-filled cellulose acetate capsules. Owing to the thermoplastic properties of the cellulose acetate, the capsules formed with the bulk mixing demonstrated a significant expansion when exposed to an increased temperature. Such expanded capsules hold great promise as building blocks in lightweight materials.

Selective separation using efficient high-performance nanofiltration membranes has the potential for widespread application in multiple fields, including dye desalination, industrial wastewater treatment, and resource recovery from different feed streams. This study focused on the design of selective and self-cleaning nanofiltration membranes by incorporating iron aminoclay nanoparticles in a piperazine-based polyamide active layer supported on an ultrafiltration PAN substrate. Fe-AC nanoparticles and thin film nanocomposites (TFNC) were characterized for their morphology, surface chemistry, roughness, and surface area. In terms of wettability/hydrophilicity, TFNC membranes with Fe-AC incorporated had the lowest contact angle of 33.5 degrees, while that of the pristine TFNC0 membrane was 60.5 degrees. They also had a higher surface negative zeta potential and smoother surface morphology. The TFNC membranes also exhibited higher water fluxes and enhanced selectivity towards molecular separation compared to the control membranes. The water flux of the optimized AC polyamide membrane, TFNC3, was 19.70 +/- 0.5 LMH (L. m- 2.h-1), while that of the pristine TFNC0 membrane was 4.85 +/- 0.6 LMH at 4 bar. 98.0-99.0 % rejection of model organic moieties was achieved at a constant flux (Congo red, Eriochrome Black T, methylene blue, Rhodamine 6G, and Crystal violet). When simulated wastewater was purified, the Fe-AC TFNC showed 98.0 % rejection of dyes and 20.0 % rejection of inorganic salts. In long-term filtration studies (>210 h) using simulated wastewater spiked with multiple foulants, >98.0 % rejection of organic matter and foulants was recorded with a stable long-term flux profile. A leaching study confirmed that the membranes were structurally stable, even after the self-cleaning process and at elevated temperatures, without any significant reduction in flux or rejection. Comparing the fouling performance between TFNC3 membranes and commercial reverse osmosis (RO) membranes, the FDR and Flux Recovery Ratio (FRR) values of commercial RO membranes were 58.0 % and 73.0 %, while those of TFNC3 were 47.0 % and 97.0 %, respectively. The results show that the membranes have lower fouling values and higher FRR values when iron clay is present. These results demonstrate the potential of the membranes for effective pre-treatment of various industrial wastewaters and selective separation.

Chemically bonded nonwovens are strong, paper-like materials that traditionally contains a latex binder comprising a plastic polymer and (often) cellulosic fibers. With this composition, these materials are only partly biobased, having a low biodegradability and cannot be recycled in traditional waste streams. In the strive for a fully biobased nonwoven system with a hydrophobic character, a biobased binder (polyelectrolyte complex, PEC) out of carboxymethyl cellulose and chitosan dissolved in citric acid) was here combined with pea protein (PP). By varying the fat content in the pea protein, as well as the content of the protein in the binder, it was possible to obtain different degrees of cellulosic nonwoven hydrophobicity and mechanical properties. At equal amounts of PEC and PP, the cured system showed a contact angle of & AP;120 degrees, which was stable in time. As compared to the binder-free nonwoven, the dry strength was doubled in the presence of defatted PP, and the stiffness and strength in the wet state was significantly higher for all combinations between PEC and PP.

The inherent colloidal dispersity (due to length, aspect ratio, surface charge heterogeneity) of CNCs, when produced using the typical traditional sulfuric acid hydrolysis route, presents a great challenge when interpreting colloidal properties and linking the CNC film nanostructure to the helicoidal self-assembly mechanism during drying. Indeed, further improvement of this CNC preparation route is required to yield films with better control over the CNC pitch and optical properties. Here we present a modified CNC-preparation protocol, by fractionating and harvesting CNCs with different average surface charges, rod lengths, aspect ratios, already during the centrifugation steps after hydrolysis. This enables faster CNC fractionation, because it is performed in a high ionic strength aqueous medium. By comparing dry films from the three CNC fractions, discrepancies in the CNC self-assembly and structural colors were clearly observed. Conclusively, we demonstrate a fast protocol to harvest different populations of CNCs, that enable tailored refinement of structural colors in CNC films.

Radiative cooling forms an emerging direction in which objects are passively cooled via thermal radiation to cold space. Cooling materials should provide high thermal emissivity (infrared absorptance) and low solar absorptance, making cellulose an ideal and sustainable candidate. Broadband solar-reflective or transparent coolers are not the only systems of interest, but also more pleasingly looking colored systems. However, solutions based on wavelength-selective absorption generate not only color but also heat and thereby counteract the cooling function. Intended as coatings for solar cells, we demonstrate a transreflective cellulose material with minimal solar absorption that generates color by wavelength-selective reflection, while it transmits other parts of the solar spectrum. Our solution takes advantage of the ability of cellulose nanocrystals to self-assemble into helical periodic structures, providing nonabsorptive films with structurally colored reflection. Application of violet-blue, green, and red cellulose films on silicon substrates reduced the temperature by up to 9 °C under solar illumination, as result of a combination of radiative cooling and reduced solar absorption due to the wavelength-selective reflection by the colored coating. The present work establishes self-assembled cellulose nanocrystal photonic films as a scalable photonic platform for colored radiative cooling.

Chemically-bonded nonwoven is commonly used in single-use products, and are often composed of cellulose fibers with a fossil-based binder. To reduce the amount of plastic littering, we investigated a biobased and biodegradable binder consisting of polyelectrolyte complexes based on chitosan, carboxymethyl cellulose and citric acid. The binder significantly improved the mechanical properties of two different types of cellulosic fiber systems in both dry and wet states. The quality of the water used in the binder had a significant impact on the mechanical properties, especially in the dry state, indicating a beneficial effect by the presence of cations. It was shown that covalent bonds were formed during the low temperature drying, and that the amount of bonds increased with a high temperature curing. Electron microscopy and tensile data indicated that the binder acted as a joint between the fiber/fiber parts. The presented results enable a sustainable solution for the current plastic-based nonwoven industry.

Soot nanoparticles, that are considered as pollutants, have been utilized in the fabrication of a high-performance sodium-ion battery anode, which exhibits comparable electrochemical cycling as those prepared from commercial hard carbon materials.