ABSTRACT This study investigates the complexation of long-chain carboxymethylcellulose sodium salt (NaCMC) with short-chain quaternized poly(4-vinylpyridine) (QP4VP). The novelty of this work lies in how the pH-dependent behavior of the polysaccharide derivative influences its conformation, which, in turn, impacts the polyelectrolyte complexes (PECs) formed. The study uses the polyanion NaCMC below its critical overlap concentration (C * = 0.2 wt%), ensuring the dominance of NaCMC – QP4VP interactions over NaCMC self-associations to yield soluble complexes. Complexation occurs through electrostatic interactions between carboxylate groups (COO¯) and pyridinium sites (4VPH+), along with hydrogen bonding, as validated by UV-visible spectroscopy, conductivity, and pH measurements. The manuscript also discusses the possibilities of interactions between the functional groups of both polyions. These interactions govern the appearance of insoluble zones of complexed segments and soluble zones of non-complexed segments within the material. Transmittance at 500 nm and zeta potential measurements confirm these zones. Those possibilities change based on the pH of NaCMC, which controls the ratio of COOH/COO¯ groups along the NaCMC chains. SEM imaging reveals a 3D porous network with features ranging from 175 nm to 23 µm, and TGA quantifies the contributions of each polyelectrolyte in the PEC.

ABSTRACT This study presents fabrication and analysis of carbon nanotube (CNT)/Ecoflex composites with characteristics of balanced conductivity, flexibility and mechanical robustness. We developed uniform composites using a low-viscosity CNT/Ecoflex suspension combined with a solvent evaporation technique. The electrical resistance and strain characteristics of the composites were analyzed, followed by further examination of their stress-strain behaviors. The 8.5 wt.% and 9.1 wt.% composites demonstrated higher elastic properties without compromising their conductivity. Furthermore, our exploration into tactile sensing characteristics revealed that the 2 wt.% CNT/Ecoflex composites responded optimally at a voltage of 20 V. Finally, the 1.5 wt.% CNT/Ecoflex composites were implemented in a hand motion sensor, showcasing its ability to accurately track and differentiate complex hand gestures. This work provides crucial insights into the potential of CNT/Ecoflex composites in fields requiring mechanical strength, flexibility, and consistent conductivity.

ABSTRACT Hydrogel materials have a variety of applications, ranging from biomedical materials and drug delivery systems, to their employment as immobilization matrices in bioprocessing applications. Polyvinyl alcohol (PVA) is a synthetic, water-soluble, and biocompatible polymer. Due to its physical properties when gelled, this polymer has been highlighted as a suitable candidate for application in the bioprocessing industry as an immobilization matrix for microorganisms. This study investigates the effects of using various polyols as co-solvent on the gelation of PVA-based hydrogels formed at ambient conditions, and their resulting properties. In addition to glycerol, previously known for its capabilities to improve gelation when used as co-solvent, polyols including erythritol (C4H10O4), xylitol (C5H12O5), and sorbitol (C6H14O6) were investigated. Key physical properties of the resulting PVA-based hydrogels were investigated, including: transparency; tensile and compressive strengths; diffusion coefficients; rates of gelation; and method of gelation. It was determined that the hydrogels are formed through physical crosslinking rather than chemical crosslinking. The glycerol-PVA hydrogels tended to exhibit more suitable properties for application in the immobilization of photosynthetic organisms, although the differences in properties between the glycerol-PVA, xylitol-PVA, and sorbitol-PVA hydrogels were comparable and often not significantly different after rehydration. This investigation showed that through the addition of simple polyols, solid PVA-based hydrogels could be formed at ambient conditions without the requirement of cytotoxic chemicals, harsh gelation conditions, or unfavorable intermediate chemicals.

ABSTRACT Ultraviolet curing (UV) water-based ink has the advantages of low viscosity, high gloss, and wide application range. However, there are some defects such as slow curing speed and low cross-linking degree. In this paper, the copolymer p(GMA-r-AA) was prepared via traditional radical polymerization using glycidyl methacrylate (GMA) and acrylic acid (AA) as monomers, and then p(GMA-r-AA) was modified by 2-hydroxyethyl methacrylate (HEMA) to obtain acrylic prepolymer P(GMA-r-AA)-g-HEMA with double bonds. Triethylenetetramine reacted with GMA to obtain a multifunctional reactive diluent triethylenetetramine hexamethacrylate glycidyl amide (TGMA). Fourier transform infrared (FTIR) spectroscopy combined with hydrogen nuclear magnetic resonance spectroscopy (1H NMR) was used to characterize the structures of the prepolymer P(GMA-r-AA)-g-HEMA and the reactive diluent TGMA. Three ingredients were needed to prepare UV curable ink: photoinitiator, multifunctional reactive diluent (TGMA), and acrylic prepolymer P(GMA-r-AA)-g-HEMA. The effects of the mass fraction and relative molecular weight of P(GMA-r-AA)-g-HEMA, the type and mass fraction of the photoinitiator, the number of functional groups, and the mass fraction of TGMA on the UV ink curing speed and wear resistance of the ink film were discussed. At a mass fraction of 1% for the photoinitiator TPO, the mass fraction of the reactive diluent was 55% with 4 functional groups, and the prepolymer had an average relative molecular mass of 5.63 × 104 g/mol. The UV water-based ink completed curing in 0.1 s, and the mass loss abrasion was 2–5% after 50 times. Finally, the UV ink was used to prepare UV conductive magnetic ink. The UV conductive and magnetic ink can be cured into a film in 0.1 s, no peeling phenomenon, with good magnetic properties.

ABSTRACT The introduction of graphene quantum dots (GQDs) in a pentacene field effect transistor (FET) device structure notably improved the on/off ratio, demonstrating a significant memory window. This indicates that GQDs are effective in enhancing carrier retention properties. However, the subsequent introduction of Ag nanoparticles (NPs) between the pentacene layer and GQDs led to a significant decrease in the memory window and a far smaller on/off ratio. This decrease is primarily attributed to an increase in the “off” current, suggesting a detrimental impact of Ag NPs on the device performance. The formation of an interface dipole at the Ag NPs-GQDs interface appears to be the main factor behind this effect, influencing the energy band bending and altering the flat band energy. The integration of Ag NPs into the device not only modifies the threshold voltage and elevates the “off” current through interface dipole effects, but also considerably diminishes the “on” current. This reduction is attributed to the dual influences of reduced carrier concentration resulting from screening phenomena and the obstruction of charge movement caused by interfacial scattering. This twofold effect on both the “on” and “off” currents underscores the complex influence of Ag NPs in regulating the electronic behavior of the FET device.

ABSTRACT In the present work, we report the effect of solvent content on the β-phase fraction in PVDF (poly(vinylidene fluoride)) films synthesized by the facile wet chemical route using DMF (N,N-Dimethylformamide) as the solvent. The amount of PVDF powder was kept fixed while the amount of DMF was varied. X-ray diffraction (XRD) revealed the transformation of the α-phase in the PVDF powder to β-phase in the synthesized PVDF films, which was further confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Deconvolution of the XRD profiles of the films showed the increase of the β-phase content (viz. β α ratio) with initial increase in the DMF volume. However, a surprising and previously unreported result emerged, i.e. the saturation of the β-phase beyond a certain volume of the solvent. The plausible mechanism for the formation and further saturation of the β-phase in the PVDF films is discussed.

ABSTRACT In this work, five new peptides derived from natural resources and two peptide bolaamphiphiles were designed. The self-assembling ability of the peptides and the bolaamphiphiles, as well as their predicted antioxidant activity was examined computationally. In particular, replica modeling molecular dynamics studies were carried out at three different temperatures. Results showed that the bolaamphiphiles as well as three of the peptides efficiently formed spherical or fibrous assemblies, particularly at physiological temperatures. In addition, stacking interactions and hydrogen bonds played a critical role in assembly formation. Furthermore, molecular docking studies with extracellular matrix proteins such as the triple helix motif of collagen and the fibronectin (III) motif of tenascin-X displayed binding interactions with the peptides and the bolaamphiphiles. The most optimal peptide bolaamphiphile WMYGGGWMY-CO-NH-(CH2)4-YMWGGGYMW was then synthesized in the laboratory and its ability to form functional scaffolds upon binding to collagen and tenascin-X was examined. The scaffolds were bioprinted with co-cultures of fibroblasts and keratinocytes. The cells not only proliferated over time but also showed strong adherence and spreading within the matrix. Thus, the peptides and the bolaamphiphiles studied in this work, may be potentially developed as scaffold components for tissue regeneration applications.

ABSTRACT Selenium complexes modifying their chemical structure through the variation of amino acids such as L-phenylalanine, L-histidine, and L-tryptophan were dispersed in collagen-starch hydrogels (1 wt.%), generating the (Se-F), (Se-H), and (Se-T) biomatrices, respectively. SEM/EDS analysis confirmed a uniform selenium distribution, with (Se-H) biomatrix displaying the largest aggregates, influencing the formation and size of aggregates within the biopolymer matrix. All matrices exhibited a semicrystalline nature; notably (Se-T) decreased fibrillar structure crystallinity of collagen. Physicochemical assessments revealed (Se-H) with the shortest gelation time (10 ± 1 minutes), highest swelling (4500 ± 230%) and superior resistance to proteolytic degradation. (Se-T) demonstrated the highest crosslinking index (52 ± 4%), while (Se-F) was characterized by having the highest storage modulus (840 Pa at 1 hz), enabling the sustained release of methylene blue for up to 7 days. Upon contact with commercial plant substrate, all matrices showed negligible mass variation. Biological findings showcased (Se-F) stimulating monocyte metabolism and proliferation, while (Se-H) fostered fibroblast metabolism, proliferation, and interleukin-10 (IL-10) secretion in monocytes, alongside reduced tumor necrosis factor-alpha (TNF-α) secretion. All matrices decreased TNF-α secretion in monocytes, signifying potential as advanced wound healing dressings. For plant tissue, all matrices enhanced tomato cell metabolism and proliferation. Seeds grown on commercial plant substrate revealed (Se-F) yielding plants with larger stem sizes, while (Se-T) resulted in higher leaf counts within 30 days, indicating their potential agricultural applications.

ABSTRACT A quaternary polymer paraffin inhibitor and pour point depressant (PIaPPD) with hyperbranched structure was prepared by free radical solution polymerization using docosyl methacrylate (DM), maleic anhydride (MA), methyl methacrylate (MMA) and diethylene glycol dimethacrylate (DEGDMA) as raw materials. The experimental results show that when the dosage of PIaPPD is 250 ppm, the paraffin inhibiting rate of SY1 for high waxy crude oil can reach 83.3%, and the pour point can be reduced by 16°C. At the same time, it has good universality for the crude oil of the remaining 12 different blocks of oil wells. The paraffin inhibiting rate is up to 83.3%, and the crude oil pour point can be reduced by up to 19°C. Through DSC, FTIR, fluorescent inverted microscope, polarizing microscope, XRD, SEM and carbon number distribution analysis, it can be seen that: PIaPPD achieves the purpose of paraffin inhibition and pour point depression by cocrystal-adsorption and dispersion of wax crystals. It mainly achieves the effect of paraffin inhibition and pour point depression by reducing the wax appearance temperature, inhibiting the amount of wax precipitation, destroying the normal growth structure of wax crystals, reducing the strength of wax crystals, reducing paraffin isoparaffins, and inhibiting the precipitation of most medium and low carbon paraffins and a small number of high carbon paraffins. Finally, the wax crystals exist in the crude oil in a less, small and non-aggregated, irregular state in a more dispersed form.

ABSTRACT Six new semi-IPN hydrogels using 2-acrylamido-methylpropane-1-sulfonic acid (AMPS) and Gelatin at different ratios through redox polymerization were prepared. Methylene-bisacrylamide and glutaraldehyde were used as the crosslinking agents for AMPS and Gelatin, respectively. The hydrogels’ swelling ratios and surface morphologies were analyzed using SEM for characterization. Porosity and specific surface area using the Brunauer–Emmett–Teller technique. DSC and Tg were also used for the thermal analysis of the prepared hydrogels, which show trans-glass temperature (Tg) higher than their raw materials AMPS and Gelatin. The prepared hydrogels were used to eliminate the cationic dye MB from the water-based solutions with an initial concentration of 600 ppm. The study discovered that the N9 and N10 hydrogels were extremely effective at removing a certain dye from aqueous solutions with an optimum pH level of 11 and an optimum temperature of 65°C. Both N9 and N10 achieved high removal efficiencies, reaching equilibrium at 90 min, whereas the other hydrogels required 120 min. N9 performed slightly better at 1078.919 mg/g and N10 at 1057.404 mg/g. The adsorption behavior of the two hydrogels followed the Langmuir model. The hydrogels exhibited pseudo-second-order kinetics. The thermodynamic study cleared that the adsorption of MB dye was endothermic and spontaneous. Results also showed that the adsorption of dyes with hydrogels N9 and N10 is chemisorption in nature. Desorption studies were conducted using 0.1 M HCl and NaOH. HCl was found to be the best eluent for dye recovery.