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Cationic polyelectrolytes (PEs) are commonly used additives in manufacturing of cellulose based products such as regenerated fibers and paper to tailor their product properties. Here we are studying the adsorption of poly(diallyldimethylammonium chloride), PD, on cellulose, using in situ surface plasmon resonance spectroscopy (SPR) measurements. We employ model surfaces from regenerated cellulose xanthate (CX) and trimethylsilyl cellulose (TMSC), mimicking industrially relevant regenerated cellulose substrates. The effects of the PDs molecular weight were strongly depending on the ionic strength and type of electrolyte (NaCl vs CaCl 2 ). Without electrolytes, the adsorption was monolayer-type, i.e. independent of molecular weight. At moderate ionic strength, adsorption increased due to more pronounced PE coiling, while at high ionic strength electrostatic shielding strongly reduced adsorption of PDs. Results exhibited pronounced differences for the chosen substrates (cellulose regenerated from xanthate (CX reg ) vs. regenerated from trimethylsilyl cellulose, TMSC reg ). Consistently higher adsorbed amounts of the PD were determined on CX reg surfaces compared TMSC. This can be attributed to a more negative zeta potential, a higher AFM roughness and a higher degree of swelling (investigated by QCM-D) of the CX reg substrates., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

In this study, the anti-freezing conductive hydrogel electrolytes with outstanding mechanical properties were synthesized by a facile and feasible method. The mechanical and anti-freezing properties of the synthesized polyacrylamide/lithium lhloride/water soluble cellulose acetate (PAM/LiCl/WSCA) hydrogels are significantly enhanced with the addition of WSCA and LiCl. The tensile strength and toughness of the gels were gradually increased to 341 KPa and 1.2 MJ/m 3 , respectively. The hydrogel electrolyte can remain soft and flexible at -80 °C, displaying certain elasticity and electrical conductivity. In addition, the super-capacitor assembled with PAM/LiCl/WSCA hydrogel as electrolyte showed excellent stability in capacitance retention after 500 times of folding cycles and 10,000 times of charge and discharge tests. The capacitor still maintains 64.64 % of its capacity at -40 °C. This facile strategy to fabricate anti-freezing conductive hydrogel electrolyte provides a new idea and way to the application of hydrogels as electrolytes in extreme cold environments., (Copyright © 2021. Published by Elsevier Ltd.)

Although aqueous zinc-ion batteries (ZIBs) are promising for scalable energy storage application, the actual performance of ZIBs is hampered by the irreversibility. Optimization of electrolyte composition is a relatively practical and facile way to improve coulombic efficiency (CE) and Zn plating/stripping reversibility of ZIBs. N,N-Dimethylacetamide (DMA) has a higher Gutmann donor number (DN) than that of H 2 O, abundant polar groups, and economic price. Herein, a mixture electrolyte containing 10 vol% DMA and ZnSO 4 , which has an enhanced Zn reversibility almost fourfold higher than that of pure ZnSO 4 electrolyte, is demonstrated. The density functional theory (DFT) calculation and spectroscopic analysis reveal DMA has the ability to reconstruct the solvation structure of Zn 2+ and capture free water molecules via forming Hbonds. The inhibited dendrite growth on Zn anode is further clarified by an in situ characterization. This work provides a feasible way for the development of long-lifespan ZIBs., (© 2022 Wiley-VCH GmbH.)

This work reports a simple method to form and visualize individual polyelectrolyte-nanoparticle necklace-like structures on paper, which is applicable to other porous surfaces. In this work, one-dimensional necklaces of negatively charged gold nanoparticles (AuNPs) have been electrostatically assembled along the backbone of a cationic polyacrylamide (CPAM) chain adsorbed on paper. The process involves rapidly passing a dilute CPAM solution through filter paper, adsorbing the polyelectrolyte on the surface, followed by the immediate filtration of an AuNP suspension through the same filter paper. The nanoparticles used were negatively charged, citrate ion capped AuNPs with an average diameter of 20 nm. Scanning electron microscopy images of the dried paper sample showed that the AuNP necklaces were adsorbed in a perpendicular direction to that of the cellulose fibers and along the length of the CPAM molecules which were draped over the fibers. The effects of CPAM polymer concentration, charge density, and molecular weight on such assembly of AuNPs were studied. This technique enables the visualization of polyelectrolyte molecules and the formation of very well organized and reproducible polyelectrolyte-nanoparticle necklaces on a porous, three-dimensional substrate., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Aqueous layer-by-layer (LbL) processing was used to create polyelectrolyte multilayer (PEM) nanocomposites containing cellulose nanocrystals and poly(allylamine hydrochloride). Solution-dipping and spin-coating assembly methods gave smooth, stable, thin films. Morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and film growth was characterized by X-ray photoelectron spectroscopy (XPS), ellipsometry, and optical reflectometry. Relatively few deposition cycles were needed to give full surface coverage, with film thicknesses ranging from 10 to 500 nm. Films prepared by spin-coating were substantially thicker than solution-dipped films and displayed radial orientation of the rod-shaped cellulose nanocrystals. The relationship between film color and thickness is discussed according to the principles of thin film interference and indicates that the iridescent properties of the films can be easily tailored in this system.

Anionic groups (AGs) on different cellulosic fiber surfaces were investigated by methylene blue (MB) and polyelectrolyte (PE) sorption, X-ray photoelectron spectroscopy (XPS), and total attenuated reflectance infrared spectrometry (FTIR-ATR). The MB sorption isotherms fitted well the Langmuir equation that gave consistent estimations of sorption capacities. FTIR-ATR showed that MB molecules had extensive accessibility to the fiber wall pores. Estimation of surface AGs by PE sorption gave much higher values than a new method combining MB sorption and XPS measurements (MB-XPS). The surface AGs in different cellulosic fibers accounted for 1-3% of the total AG content as revealed by MB-XPS. It was suggested that PE molecules can penetrate the fiber wall and form loops or unattached segments at external fiber surfaces that disrupt the PE sorption stoichiometry. The competition of MB and PE for the anionic sites in papermaking was assessed and it was shown that MB ions have a much stronger affinity to AGs than PE molecules.