The adsorption of carboxymethylcellulose (CMC) on cellulose surfaces is one of the most studied examples of the adsorption of an anionic polyelectrolyte on a like-charged surface. It has been suggested that divalent ions can act as a bridge between CMC chains and the surface of cellulose and enhance the CMC adsorption: they can, however, also alter the structure of CMCs in the solution. In previous investigations, the influence of cations on solution properties has been largely overlooked. This study investigates the effect of Ca²⁺ ions on the properties of CMC solutions as well as the influence on cellulose nanofibers (CNFs), which was studied by dynamic light scattering and correlated with the adsorption of CMC on a cellulose surface probed using QCM-D. The presence of Ca²⁺ facilitated the multichain association of CMC chains and increased the hydrodynamic diameter. This suggests that the adsorption of CMCs at high concentrations of CaCl₂ is governed mainly by changes in solution properties rather than by changes in the cellulose surface. Furthermore, an entropy-driven mechanism has been suggested for the adsorption of CMC on cellulose. By comparing the adsorption of CMC from H₂O and D₂O, it was found that the release of water from the cellulose surface is driving the adsorption of CMC.

Integration of fiber modification step with a modern pulp mill is a resource efficient way to produce functional fibers. Motivated by the need to integrate polymer adsorption with the current pulping system, anion-specific effects in carboxymethylcellulose (CMC) adsorption have been studied. The QCM-D adsorption experiments revealed that CMC adsorption to the cellulose model surface is prone to anion-specific effects. A correlation was observed between the adsorbed CMC and the degree of hydration of the co-ions present in the magnesium salts. The presence of a chaotropic co-ion such as nitrate increased the adsorption of CMC on cellulose compared to the presence of the kosmotropic sulfate co-ion. However, anion-specificity was not significant in the case of salts containing zinc cations. The hydration of anions determines the distribution of the ions at the interface. Chaotropic ions, such as nitrates, are likely to be distributed near the chaotropic cellulose surface, causing changes in the ordering of water molecules and resulting in greater entropy gain once released from the surface, thus increasing CMC adsorption.

Solid‐state photosynthetic cell factories (SSPCFs) are a new production concept that leverages the innate photosynthetic abilities of microbes to drive the production of valuable chemicals. It addresses practical challenges such as high energy and water demand and improper light distribution associated with suspension‐based culturing; however, these systems often face significant challenges related to mass transfer. The approach focuses on overcoming these limitations by carefully engineering the microstructure of the immobilization matrix through freeze‐induced assembly of nanochitin building blocks. The use of nanochitins with optimized size distribution enabled the formation of macropores with lamellar spatial organization, which significantly improves light transmittance and distribution, crucial for maximizing the efficiency of photosynthetic reactions. The biomimetic crosslinking strategy, leveraging specific interactions between polyphosphate anions and primary amine groups featured on chitin fibers, produced mechanically robust and wet‐resilient cryogels that maintained their functionality under operational conditions. Various model biotransformation reactions leading to value‐added chemicals are performed in chitin‐based matrix. It demonstrates superior or comparable performance to existing state‐of‐the‐art matrices and suspension‐based systems. The findings suggest that chitin‐based cryogel approach holds significant promise for advancing the development of solid‐state photosynthetic cell factories, offering a scalable solution to improve the efficiency and productivity of light‐driven biotransformation.

The following study is a continuation of the previous work on preparation of gastro-resistant films by incorporation of cellulose acetate phthalate (CAP) into the soft gelatin film. An extended investigation on the previously described binary Gelatin-CAP and ternary Gelatin-CAP-carrageenan polymer films was performed. The results suggest that the critical feature behind formation of the acid-resistant films is a spinodal decomposition in the film-forming mixture. In the obtained films, upon submersion in an acidic medium, gelatin swells and dissolves, exposing a CAP-based acid-insoluble skeleton, partially coated by a residue of other ingredients. The dissolution-hindering effect appears to be stronger when iota-carrageenan is added to the film-forming mixture. The drug release study performed in enhancer cells confirmed that diclofenac sodium is not released in the acidic medium, however, at pH 6.8 the drug release occurs. The capsules prepared with a simple lab-scale process appear to be resistant to disintegration of the shell structure in acid, although imperfections of the sealing have been noticed.

Binders are essential components in battery systems that maintain the electrode structure and integrity throughout cycling. The choice of binder affects processing, electrochemical behavior, and end-of-life recovery. The widely used poly(vinylidene difluoride) (PVDF) binder is increasingly scrutinized since it is a polyfluoroalkyl compound and requires processing in organic solvents like N-methyl-2-pyrrolidone. Consequently, efforts are underway to identify more sustainable options. In this work, we present chitin nanofibers (ChNFs), derived from fisheries waste, as a biobased, fluorine-free alternative that enables fully aqueous electrode fabrication. ChNFs disperse more than 90% of graphite in water without the need for auxiliary agents such as surfactants. Colloidal probe microscopy shows that adhesion between protonated ChNFs and graphite depends on pH, likely being governed by cation-π interactions. This strong affinity facilitates the remarkable dispersing capability of ChNFs through a multifaceted mechanism. Adsorbed nanofibers confer electro-steric stabilization by extension into the aqueous phase. The strong ChNF network can physically entrap larger particles, greatly enhancing the long-term stability of ChNF-graphite suspensions. The ChNF-graphite dispersion exhibits rheological behavior suited for forming uniform electrode coatings. Electrodes prepared with 4% ChNFs deliver specific capacities of 370 mA h g^-1 and enhanced capacity retention over 100 cycles compared to PVDF-based counterparts. Electron microscopy, X-ray photoelectron spectroscopy, and online electrochemical mass spectrometry analyses reveal that the nature of the binder dictates the solid electrolyte interphase (SEI) characteristics. The ChNF produces a more robust and stable SEI that suppresses electrolyte reduction, directly contributing to the enhanced electrochemical performance.