Paper-based packaging represents a viable alternative for reducing plastic usage. To tailor material performance, wax coatings with distinct crystallization behaviors are employed. One coating system of particular interest is a blend of low-molecular-weight ethylene glycol distearate (EGDS) and fully substituted cellulose stearoyl ester (CSE). Upon cooling from the melt under ambient conditions, this blend forms superficial crystalline structures on the micrometer scale, enabling its function as a regenerable, superhydrophobic paper coating. This study investigates the co-crystallization behavior of EGDS and CSE, focusing on the spontaneous out-of-plane growth of crystallites without significant energy input. Initially, the crystallization of pure EGDS was characterized. Subsequently, the interaction of EGDS wax with biobased CSE polymer was examined in detail using calorimetric analysis, scattering techniques, and NMR spectroscopy, respectively. The influence of the side chain length of the cellulose ester, and its impact on chemical compatibility with EGDS, was also considered. The system exhibits phase mediation through the insertion of polymeric aliphatic side chains into the EGDS structure and the formation of CSE side-chain crystallites, which serve as nucleation sites for subsequent EGDS crystallization. This allows the controlled tuning of crystalline morphology and thus broaden its applicability in sustainable material development for advanced applications.

Fatty acid cellulose esters (FACEs) have great potential as biogenic alternatives to petroleum-based plastics. Nevertheless, their thermal property profiles have been the subject of controversial discussion, particularly with respect to their crystallization behavior. A thorough understanding of the crystallization behavior of FACEs is fundamentally important for gaining deep insights into their solid-state characteristics and thermal properties. This systematic study succeeds in elucidating the crystallization behavior of FACEs as bulk materials. Differential scanning calorimetry combined with rheological analysis and X-ray diffraction of cellulose esters bearing side chains with varying numbers of fatty acid residues (C-12-C-20) and degrees of substitution (ranging from partial to full esterification, i.e., 0.1-3.0) revealed that crystallization of FACEs occurs in multiple stages. These stages involve the distinct crystallization of inter and intramolecular side chains and polysaccharide backbones. A quantitative multistep crystallization mechanism is proposed based on the study findings.

AbstractPaper finishing, in particular, coating paper with desired barrier functions is well‐developed as of today. However, due to large amounts of material and process energy as well as the use of non‐renewable resources for such coatings, common technologies are not sustainable. Given the increasing importance of paper in manifold applications, more sustainable routes with low‐energy processes as well as biogenic material alternatives are highly needed. To address this challenge, a solvent‐free and material‐efficient approach is proposed to bio‐based paper coatings by depositing chia oil‐based plasma polymers using a jet‐induced sliding discharge concept at atmospheric pressure. Depending on the amount of coating and the paper porosity, this treatment retards water absorption. Coating visualization is enabled through confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Like chia oil, safflower oil, and olive oil show the ability to hydrophobize paper and the great potential within plasma polymerized vegetable oils to make the paper coating more sustainable.

For a wide range of applications, paper materials require effective protection against the destructive effect of water, which is most effectively realized by superhydrophobic coatings. In recent years, a considerable amount of scientific research has been carried out in this area, focusing particularly on biogenic resources. With this contribution, we go one step further and examine how biogenic materials can be transferred into aqueous dispersions and coated onto paper via existing technologies. With this paper coating, based on a hydrophobic cellulose derivative in combination with a structurally similar wax, thermally regenerable flower-like surface morphologies are obtained via self-assembly, where the hydrophobic cellulose polymer acts as a structural template for the co-crystallization of the wax component. Such hydrophobic structures in the low micrometer range ensure perfectly water-repellent paper surfaces with contact angles > 150° starting from coating weights of 5 g/m2. The dispersion can be successfully applied to a variety of commercially available paper substrates, whereby the effects of different roughness, porosity, and hydrophobicity were investigated. In this context, a certain roughness of the base paper (Sa ~ 1.5–3 µm) was found to be beneficial for achieving the highest possible contact angles. Furthermore, the approach proved to be paper process-compatible, recyclable, and regenerable, whereby the processing temperatures allow the coating properties to be thermally generated in situ. With this work, we demonstrate how biogenic waxes are very well suited for superhydrophobic, regenerative coatings and, importantly, how they can be applied from aqueous coatings, enabling simple transfer into the paper industry.

Cellulose ferulate, synthesized by Mitsunobu reaction, is shaped into thin films and also used as an aqueous dispersion to perform artificial lignin polymerization on anchor groups. This biomimetic approach is carried out in a Quartz crystal microbalance with a dissipation monitoring (QCM-D) device to enable online monitoring of the dehydrogenation, applying H 2 O 2 and adsorbed horseradish peroxidase (HRP). The systematic use of phenylpropanoids with different oxidation states, i.e., ferulic acid, coniferyl aldehyde, coniferyl alcohol, and eugenol allowed to conclude structure-property relationships. Both the deposited material, as well as the surface roughness increased with the hydrophobicity of the monomers. Beyond surface characterizations, py-GC-MS, HSQC NMR spectroscopy and Size exclusion chromatography (SEC) measurements revealed the linkage types β-β, β-5, 5-5, and β-O-4, as well as the oligomeric character of the dehydrogenation products. All samples possessed an antibacterial activity against B. subtilis and can be used in the field of antimicrobial biomaterials.

Atmospheric pressure plasma polymerization represents a promising coating technology, addressing drawbacks of traditional processes (solvent use, multistep procedures, etc.) while enabling deposition of thin cross-linked polymer layers with high contour fidelity. We address technological challenges with a novel plasma device that integrates multiple plasma source benefits and investigate the suitability of two plant-based precursors, chia and tung oil, for plasma polymerization to hydrophobize glass and paper. Chia oil enables the deposition of thin, covalently bonded hydrophobic polymer layers. Such coatings have diverse applications especially inside the paper industry, where water repellents in the form of internal and surface sizing have always been an essential functionalization step. Using bio-based precursors and reducing extra chemicals contributes to substituting fossil-based or harmful substances. Generation of biomimetic layers from vegetable oils on paper by plasma-enhanced chemical vapor deposition at atmospheric pressure. image

Abstract This study identifies important factors for designing an effective biomimetic paper‐based fog harvesting substrate by examining the harvesting properties of different surfaces, including glass, polyethylene, and superhydrophobic paper. In laboratory‐scale fogging tests, the wetting behavior of the substrates is characterized, and the importance of the tilt angle of the respective surface relative to the fog flow is elaborated. Because successful fog harvesting requires both efficient accumulation of water droplets on the surface (by condensation and collision) and sufficient but not excessive roll‐off of the liquid, the amount of water finally collected is clearly related to the pinning effect, which should prevent the smallest droplets from being carried away by the wind but must not lead to full and permanent wetting of the surface. Coalescence is identified as a major phenomenon to improve droplet roll‐off. In this context, superhydrophobic paper indicates to be a more effective water collector than glass or polyethylene, especially when oriented vertically, since it allows the droplets to roll off very efficiently. Finally, the addition of glass particles to the superhydrophobic coating is proposed as a means of enhancing pinning and improving the fog harvesting efficiency.

Enhancing paper hydrophobicity is of key importance for many paper-based applications. Fatty acids or vegetable oils and their derivatives replace environmentally harmful conventional coating materials but still require challenging chemical reactions for covalent attachment onto paper. Here, we show that simple storage of olive oil-coated cotton linter paper at 70 °C and subsequent Soxhlet extraction is able to endow paper with hydrophobic properties, reaching water contact angles above 130°. In-depth chemical and morphological analytics show the relevance of temperature and air accessibility during the aging process compared with aging at ambient temperature and under the exclusion of oxygen, underlining the importance of assessing a coating’s long-term performance and stability under diverse storage conditions. Simple storage of vegetable oil-coated paper at elevated temperatures followed by extraction proves to be an easy way to produce stable covalently attached hydrophobic paper coatings with exceptionally low coating amounts.

Plasma-enhanced chemical vapor deposition is a highly promising tool for coating deposition due to its versatility, tunability, low chemical consumption, and cost-effectiveness, with an increasing scope of deposition methods at both low and atmospheric pressure. Adhering to green chemistry principles, biobased precursors have recently shifted into the focus of research interests. This review gives an overview of the main biogenic substance classes that have been used for the deposition of plasma polymer coatings, including natural oils, terpenes, enzymes, and lactic acid-based precursors. The common feature of these precursors is not only their biogenic origin, but additionally the manifold properties of the resulting plasma-deposited thin films, ranging from antimicrobial properties to tunable surface-wetting characteristics, electrical conductivity, or biodegradability. This combination of unique features makes plasma-derived polymers based on natural precursors immensely attractive for manifold applications.

Poly(butylene succinate-co-adipate) (PBSA) degradation and its plastisphere microbiome in cropland soils have been studied; however, such knowledge is limited in the case of forest ecosystems. In this context, we investigated: i) the impact of forest types (conifer and broadleaved forests) on the plastisphere microbiome and its community assembly, ii) their link to PBSA degradation, and iii) the identities of potential microbial keystone taxa. We determined that forest type significantly affected microbial richness (F = 5.26-9.88, P = 0.034 to 0.006) and fungal community composition (R2 = 0.38, P = 0.001) of the plastisphere microbiome, whereas its effects on microbial abundance and bacterial com-munity composition were not significant. The bacterial community was governed by stochastic processes (mainly homogenizing dispersal), whereas the fungal community was driven by both stochastic and deterministic processes (drift and homogeneous selection). The highest molar mass loss was found for PBSA degraded under Pinus sylvestris (26.6 +/- 2.6 to 33.9 +/- 1.8 % (mean +/- SE) at 200 and 400 days, respectively), and the lowest molar mass loss was found under Picea abies (12.0 +/- 1.6 to 16.0 +/- 0.5 % (mean +/- SE) at 200 and 400 days, respectively). Important fungal PBSA decomposers (Tetracladium) and atmospheric dinitrogen (N2)-fixing bacteria (symbiotic: Allorhizobium- Neorhizobium-Pararhizobium-Rhizobium and Methylobacterium and non-symbiotic: Mycobacterium) were identified as potential keystone taxa. The present study is among the first to determine the plastisphere microbiome and its commu-nity assembly processes associated with PBSA in forest ecosystems. We detected consistent biological patterns in the forest and cropland ecosystems, indicating a potential mechanistic interaction between N2-fixing bacteria and Tetracladium during PBSA biodegradation.

Hydrophobic coatings are of utmost importance for many applications of paper-based materials. However, to date, most coating methods demand vast amounts of chemicals and solvents. Frequently, fossil-based coating materials are being used and multiple derivatization reactions are often required to obtain desired performances. In this work, we present a solvent-free paper-coating process, where olive oil as the main biogenic component is being used to obtain a hydrophobic barrier on paper. UV-induced thiol-ene photocrosslinking of olive oil was pursued in a solvent-free state at a wavelength of 254 nm without addition of photoinitiator. Optimum reaction conditions were determined in advance using oleic acid as a model compound. Paper coatings based on olive oil crosslinked by thiol-ene reaction reach water contact angles of up to 120°. By means of Fourier transform infrared spectroscopy and differential scanning calorimetry, a successful reaction and the formation of a polymer network within the coating can be proven. These results show that click-chemistry strategies can be used to achieve hydrophobic polymeric paper coatings while keeping the amount of non-biobased chemicals and reaction steps at a minimum.

We discovered a biological mechanism supporting microbial degradation of bio-based poly(butylene succinate-co-adipate) (PBSA) plastic in soils under ambient and future climates. Here, we show that nitrogen-fixing bacteria facilitate the microbial degradation of PBSA by enhancing fungal abundance, accelerating plastic-degrading enzyme activities, and shaping/interacting with plastic-degrading fungal communities.

The characterization of pore sizes in paper is an important parameter, as numerous modifications of paper fibers influence or even aim to change them. yet, most methods for determining pore size only work in the absence of water (e.g. mercury porosimetry or computed tomography). However, the influence of swelling on pore size caused by water is of great interest, especially, but not only, for the porous material paper. Here we present a new method for determining the characteristic pore radius of paper sheets, being in direct contact with water. We call our device “porosity centrifuge”, in which the capillary forces that develop during the wetting and swelling process within a paper sheet are counter-balanced by a matching centrifugal force. While the capillary pressure is determined by the pore radius of the porous structure, some paper intrinsic parameters lead to a reduction from the predicted imbibition distance calculated from the force balance between centrifugal and capillary forces. Since we are able to modulate the degree of this reduction by changing the fiber type or by applying various fiber pretreatments, such as beating, reduction of fines content or calendering, we refer to it as “substrate coefficient”. Our method enables a simple and fast determination of characteristic pore radii in paper sheets using water as liquid.

Abstract To improve the reactivity of lignin for incorporation into high value polymers, the introduction of amines via Mannich reaction is a commonly used strategy. During this functionalization reaction, intra- as well as intermolecular lignin–lignin crosslinking occurs, which can vastly change the elastic properties of the lignin, and therefore, the properties of the resulting polymer. Therefore, the molecular structure of the amine that is used for such a lignin functionalization may be of great importance. However, the relationship between the molecular structure of the amine and the elastic properties of the lignin-based polymer that is generated thereof, has not been fully understood. Herein, this relationship was investigated in detail and it was observed that the molecular flexibility of the amines plays a predominant role: The use of more flexible amines results in an increase in elasticity and the use of less flexible amines yields more rigid resin material. In addition to the macroscopic 3-point bending flexural tests, the elastic modules of the resins were determined on the nanometer scale by using atomic force microscopy (AFM) in the PeakForce tapping modus. Thus, it could be demonstrated that the intrinsic elasticities of the lignin domains are the main reason for the observed tendency.

Decomposition by microorganisms of plastics in soils is almost unexplored despite the fact that the majority of plastics released into the environment end up in soils. Here, we investigate the decomposition process and microbiome of one of the most promising biobased and biodegradable plastics, poly(butylene succinate-co-adipate) (PBSA), under field soil conditions under both ambient and future predicted climates (for the time between 2070 and 2100). We show that the gravimetric and molar mass of PBSA is already largely reduced (28-33%) after 328 days under both climates. We provide novel information on the PBSA microbiome encompassing the three domains of life: Archaea, Bacteria, and Eukarya (fungi). We show that PBSA begins to decompose after the increase in relative abundances of aquatic fungi (Tetracladium spp.) and nitrogen-fixing bacteria. The PBSA microbiome is distinct from that of surrounding soils, suggesting that PBSA serves as a new ecological habitat. We conclude that the microbial decomposition process of PBSA in soil is more complex than previously thought by involving interkingdom relationships, especially between bacteria and fungi.

This scientific−technical approach describes a unique self‐structuring coating material made of wax and polysaccharide derivatives, which results in extremely water‐repellent properties if applied to solid surfaces. When cooling the coating down from the molten state, the material forms a nanostructured superhydrophobic surface within seconds. This possibility of a fast thermally induced regeneration of nanoscale surface textures creates the potential to restore superhydrophobic coating properties even after mechanical damage caused, among others, by long‐term use and complex processing and machining steps. Therefore, this coating material has great potential for engineering applications such as superhydrophobic wettability of paper surfaces. Depending on a particular application, there are different requirements for the interaction of paper with water. The highest possible water resistance, which is achieved by superhydrophobic properties, is a quality feature for a majority of paper products, such as packaging materials or novel construction materials, since the ingress of moisture is a major cause of paper damage.

This contribution reports an efficient method for the production and use of biocide-loaded cellulose acetate nanoparticles. As well-known model biocides 4-Hexylresorcinol and Triclosan were used for in situ nanoparticle loading during a nanoprecipitation process. We show that the nanoparticle size can be well-controlled by variation of the cellulose acetate concentration during nanoprecipitation. Apart from strong evidence suggesting cellulose acetate particle formation according to a nucleation-aggregation mechanism, we further show that the biocide loading of the particles occurs by a diffusion process and not via co-precipitation. The quantity of particle loading was analyzed by 1H-NMR spectroscopy of re-dissolved nanoparticles, and it was observed that a decisive factor for high packaging efficiency is the use of a biocide with low water solubility and high hydrophobicity. SEM studies showed no influence on the particle morphology or size by both biocides 4-Hexylresorcinol and Triclosan. Finally, an aqueous nanoparticle dispersion can be coated onto model paper sheets to yield pronounced antimicrobial surface-properties. Nanoparticles loaded with the biocide Triclosan showed a high antimicrobial activity against Bacillus subtilis, a cellulase producing bacteria, if applied to model paper substrates, even at extremely low coating weights of 1–5 g/m2, respectively. Additional long-term efficacy renders these nanoparticles ideal for various applications.

In paper-based devices, capillary fluid flow is based on length-scale selective functional control within a hierarchical porous system. The fluid flow can be tuned by altering the paper preparation process, which controls parameters such as the paper grammage. Interestingly, the fiber morphology and nanoporosity are often neglected. In this work, porous voids are incorporated into paper by the combination of dense or mesoporous ceramic silica coatings with hierarchically porous cotton linter paper. Varying the silica coating leads to significant changes in the fluid flow characteristics, up to the complete water exclusion without any further fiber surface hydrophobization, providing new approaches to control fluid flow. Additionally, functionalization with redox-responsive polymers leads to reversible, dynamic gating of fluid flow in these hybrid paper materials, demonstrating the potential of length scale specific, dynamic, and external transport control.

Moisture-responsive materials are gaining greater interest for their potentially wide applications and the readily access to moisture. In this study, we show the fabrication of moisture-responsive, self-standing films using sustainable cellulose as starting material. Cellulose was modified by stearoyl moieties at first, leading to cellulose stearoyl esters (CSEs) with diverse degrees of substitution (DSs). The films of CSE with a low DS of 0.3 (CSE0.3) exhibited moisture-responsive properties, while CSEs with higher DSs of 1.3 or 3 (CSE1.3 and CSE3) not. The CSE0.3 films could reversibly fold and unfold as rhythmical bending motions within a local moisture gradient due to the ab -and desorption of water molecules at the film surface. By spray-coating CSE3 nanoparticles (NPs) onto CSE0.3 films, moisture-responsive films with non-wetting surface were obtained, which can perform quick reversible bending movements and continuous shape transition on water. Furthermore, bilayer films containing one layer of CSE0.3 at one side and one layer of CSE3 at the other side exhibited combined responsiveness to moisture and temperature. By varying the thickness of CSE0.3 films, the minimal bending extent can be adjusted due to altered mechanical resistances, which allows a bending movement preferentially beginning with the thinner side.