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Traditional microelectrode arrays (MEAs) are limited to measuring electrophysiological activity in two dimensions, failing to capture the complexity of three-dimensional (3D) tissues such as neural organoids and spheroids. Here, we introduce a flower-shaped MEA (e-Flower) that can envelop submillimeter brain spheroids following actuation by the sole addition of the cell culture medium. Inspired by soft microgrippers, its actuation mechanism leverages the swelling properties of a polyacrylic acid hydrogel grafted to a polyimide substrate hosting the electrical interconnects. Compatible with standard electrophysiology recording systems, the e-Flower does not require additional equipment or solvents and is ready to use with preformed 3D tissues. We designed an e-Flower achieving a curvature as low as 300 micrometers within minutes, a value tunable by the choice of reswelling media and hydrogel cross-linker concentration. Furthermore, we demonstrate the ability of the e-Flower to detect spontaneous neural activity across the spheroid surface, demonstrating its potential for comprehensive neural signal recording. [ABSTRACT FROM AUTHOR]

Nanocomposites provides a unique opportunity to enhance thermal, mechanical, and waterproof resistance properties of polymer. The effectiveness of these enhancements typically depends on the optimal dispersion and interaction of nanofillers within the polymer matrix. The primary objective of this study is to provide direct chemical evidence for electrostatic interactions between Laponite nanofiller and polyacrylic acid. Samples were prepared by mixing Laponite dispersion and aqueous polyacrylic acid (PAA) that were adjusted to various pH conditions. We observed, an IR peak shift in the carbonyl peak of PAA and Si–O peak of Laponite to lower wave number in nanocomposite, with the maximum shift at pH 7. UV–Vis results also showed a hypsochromic shift in the carbonyl peak of PAA due to the interaction with Laponite. The extent of peak shift in IR, and UV–Vis region for the PAA-Laponite dispersion was found to be influenced by the molar mass of PAA used in the formulation of Laponite-PAA nanocomposite and pH of the medium. These results along with zeta potential measurements strongly suggest that electrostatic forces are in play between deprotonated PAA and the positively charged rim of Laponite in promoting electrostatic interactions between Laponite and PAA. The findings of the study can have a strong bearing on the design of next generation high performance coatings, sealants, and adhesives. [ABSTRACT FROM AUTHOR]

Phosphorous‐based polymeric scale and corrosion are widely used for industrial water treatment. In this paper, phosphorous acid modified polyamidoamine dendrimer (PDD) was prepared for scale inhibition and corrosion inhibition and compared with the existing inhibitors, 2‐phosphonobutane‐1,2,4‐tricarboxylic acid (PBTCA) and polyacrylic. The scale inhibition efficiency of CaCO3 was evaluated using the static scale inhibition and conductivity method. Compared to polyacrylic acid, the dendritic structure can effectively improve the calcium carbonate scale inhibition performance of the scale inhibitor. When the concentration of PDD is 40 mg/L, the scale inhibition rate is 96%, which is higher than the scale inhibition rate of 91% for PBTCA. The conductivity experimental results reveal that PDD endows the solution with higher supersaturation degree than that of PBTCA at the same concentration. Furthermore, the nucleation induction period of PDD is 1300 s, which is more than twice that of PBTCA at a concentration below 20 mg/L. The XPS, XRD, and SEM results exhibited that PDD can adsorb on the surface of calcium carbonate crystals, changing the crystals from stable calcite to metastable aragonite and vaterite. In addition, electrochemical measurements show a corrosion inhibition rate of 82.67% at a PDD concentration of 100 mg/L. This article provides data support for the application of phosphorous acid functionalization PAMAM in scale and corrosion inhibition. [ABSTRACT FROM AUTHOR]

Conductive biohydrogel received prominent application in the diverse field. Hydrogel based on biopolymer is generally biocompatible and degradable but exhibiting poor conductivity. To enhance the conductivity of biohydrogel, composite of bioplomer and synthetic polymer are preferred. This work aims to prepare such composite for the augmentation of conductivity of biohydrogel. Gum Ghatti (GG), a natural biopolymer, was grafted with polyacrylic acid and subsequently cross-linked to form a hydrogel. The synthesized hydrogel was then infused with oxidized multiwalled carbon nanotubes (-o-MWCNTs). The materials underwent comprehensive characterization using techniques, such as FT-IR, XRD, SEM, and TGA-DTA. The grafted GG demonstrated a synergistic blend of biopolymer and polyacrylic acid (AA) properties. The hydrogel's electrical conductivity was systematically investigated at varying loadings of -o-MWCNTs within the GG-cl-P(AA) matrix. As the loading of -o-MWCNTs increased from 10 to 30 mg, there was a notable enhancement in electrical conductivity. However, at higher loading amounts, the electrical conductivity exhibited a subsequent decline. [ABSTRACT FROM AUTHOR]

A novel SiO2/Al2O3/poly(acrylic acid-co-glycidyl methacrylate), SiO2/Al2O3/P(AA-co-GMA), composite was synthesized and evaluated for its effectiveness in adsorbing Co(II) ions from aqueous solutions. The composite was analyzed using various techniques including FTIR, SEM, TGA, DTA, and XRD. The composite displays a high specific surface area of 17.451 m2/g, exceeding that of the corresponding copolymer, which measures 0.236 m2/g. Batch adsorption experiments were conducted to investigate the factors influencing the adsorption capacity of the composite for Co(II) ions. In the pH experiments, it was found that at a solution pH of 3.4, the P(AA-co-GMA) copolymer alone showed limited capability in adsorbing Co(II) ions, achieving only 3.82 mg/g. However, upon integration of SiO2/Al2O3 into the polymer matrix, the composite exhibited a significantly enhanced adsorption capacity of 103.54 mg/g. The adsorption process followed a pseudo-second-order kinetic model and attained equilibrium within 60 min. The Langmuir isotherm model was found to best describe the adsorption behavior, with a maximum adsorption capacity of 217.86 mg/g. The adsorption of Co(II) was significantly affected by the ionic strength, especially with Al3+ displaying a more pronounced impact on the adsorption of Co(II) ions compared to Na+, Ca2+, and Mg2+. Thermodynamic studies indicate that the adsorption process was spontaneous and endothermic. Overall, the SiO2/Al2O3/P(AA-co-GMA) composite material displayed significant adsorption ability for Co(II) ions, making it a suitable option for further development as an effective adsorbent in water treatment applications. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable zinc‐ion batteries are emerging as green and safe energy devices owing to their high energy density and eco‐friendliness. The bottleneck is the inhomogeneous nucleation resulting in the growth of Zn dendrites and the parasitic side reactions at the anode. Herein, an electrochemical anode engineering strategy is demonstrated to curb the uncontrolled dendritic growth and side reactions. It involves the in situ generation of a solid‐electrolyte interface based on a Zn nanoparticle‐embedded poly(acrylic acid) hybrid layer (PAA‐nZn) on the anode. The homogeneously distributed polar functionalities and porous nature of the polymer regulate the uniform zinc ion flux, and the embedded zinc particle serves as nucleation sites for zinc plating. The hybrid layer reduces the nucleation overpotential and promotes instantaneous nucleation. The symmetrical cell made with PAA‐nZn@Zn has a lifecycle of >860 h with a voltage gap of 28 mV. The full cell fabricated by pairing the engineered anode with α‐MnO2 cathode showed a high discharge specific capacity of 238.3 mAh g−1 at 0.2 A g−1 with a capacity retention of 81.76% after 200 cycles and a long lifecycle. The electrochemical engineering of the anode suppresses the dendritic growth and protects the anode from unwanted side reactions and passivation. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are well known for their energy efficiency and environmental benefits. However, increasing their energy density compromises their safety. This study introduces a novel ceramic-coated separator to enhance the performance and safety of LIBs. Electrospinning was used to apply a coating consisting of an alumina (Al2O3) ceramic and polyacrylic acid (PAA) binder to a polypropylene (PP) separator to significantly improve the mechanical properties of the PP separator and, ultimately, the electrochemical properties of the battery cell. Tests with 2032-coin cells showed that the efficiency of cells containing separators coated with 0.5 g PAA/Al2O3 was approximately 10.2% higher at high current rates (C-rates) compared to cells with the bare PP separator. Open circuit voltage (OCV) tests revealed superior thermal safety, with bare PP separators maintaining stability for 453 s, whereas the cells equipped with PP separators coated with 4 g PAA/Al2O3 remained stable for 937 s. The elongation increased from 88.3% (bare PP separator) to 129.1% (PP separator coated with 4 g PAA/Al2O3), and thermal shrinkage decreased from 58.2% to 34.9%. These findings suggest that ceramic/PAA-coated separators significantly contribute to enhancing the thermal safety and capacity retention of high-energy-density LIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electron beam irradiation technology was first used to graft modify propylene separators in sodium metal batteries. • Grafted polyacrylic acid enhances electrolyte affinity and efficiently regulates Na+ ion flux. • The improved anode/separator interface enhances the cyclability and reversibility of sodium metal anodes. Sodium metal batteries (SMBs) are considered as strong alternatives to lithium-ion batteries (LIBs), due to the inherent merits of sodium metal anodes (SMAs) including low redox potential (−2.71 V vs. SHE), high theoretical capacity (1166 mAh g−1), and abundant resources. However, the uncontrollable Na dendrite growth has significantly impeded the practical deployment of SMBs. Separator modification has emerged as an effective strategy for substantially enhancing the performance of SMAs. Herein, for the first time, we present the successful grafting polyacrylic acid (PAA) onto polypropylene (PP) separators (denoted as PP-g-PAA) using highly efficient electron beam (EB) irradiation to improve the cyclability of SMAs. The polar carboxyl groups of PAA can facilitate the electrolyte wetting and provide ample mechanical strength to resist dendrite penetration. Consequently, the regulation of Na+ ion flux enables uniform Na+ deposition with dendrite-free morphology, facilitated by the favorable anode/separator interface. The PP-g-PAA separator significantly enhances the cyclability of fabricated cells. Notably, the lifespan of Na||Na symmetric cells can be extended up to 5519 h at 1 mA cm−2 and 1 mAh cm−2. The stable design of the anode/separator interface achieved through polyolefin separator modification presented in this study holds promise for the further advancement of next-generation advanced battery systems. [ABSTRACT FROM AUTHOR]

Here, we demonstrate disulfide‐crosslinked polyfluoroacrylate AB block copolymer films with excellent anti‐icing properties. The fluorinated latexes of AB block copolymers were synthesized via two‐step reversible addition‐fragmentation chain‐transfer (RAFT) emulsion polymerization using polyacrylic acid and its sodium salts as the hydrophilic A‐block, and polyhexafluorobutyl acrylate as the hydrophobic B‐block. Diacetone acrylamide was copolymerized in different blocks as a crosslinking anchor. A disulfide‐containing compound dithiodipropionic acid dihydrazide was chosen as the crosslinking agent to form disulfide‐crosslinked fluorinated films to enhance the mechanical properties, surface properties, swelling properties, and anti‐icing properties of the films. It has proved that the crosslinking site has a great impact on the film formation process which in turn affects the film performance. The B‐block crosslinked films showed better resistance to water while the A‐block crosslinked films were more organic solution resistant. The A‐block crosslinked films also possessed better anti‐icing properties due to the high F/O value. Furthermore, decrosslinking experiments were conducted using a reductant tris(2‐carboxyethyl)phosphine hydrochloride to break the disulfide bond. The recycling rate of the B‐block crosslinked films could reach >90% while the recycling rate of the A‐block crosslinked films reached >75%. [ABSTRACT FROM AUTHOR]

Cancer cell‐triggered sol–gel transformation of mineralized hydrogel (PAA‐MnO2) is designed as a facile strategy for cancer detection by manipulating the mineralization process in the presence of cancer cells. The mineralization of polyacrylic acid (PAA) with calcium phosphate via carboxyl‐Ca2+ complex is initially inhibited by the incorporation of reactive oxygen species (ROS)‐sensitive manganese oxide (MnO2) with polymer dots (PDs). In this system, the mineralization can be induced after cleaving MnO2 into Mn2+ by high ROS levels in cancer cells, forming a PAA‐MnO2 mineralized hydrogel and resulting in a naked‐eye system for cancer monitoring. Naked‐eye monitoring of ROS‐responsive sol–gel transformation is performed using a circulator device containing circulating cells to discriminate cancer (HeLa, PC‐3, B16F10) from normal cells (CHO‐K1). With the incorporation of PDs, PAA‐MnO2 mineralized hydrogel not only provides physical transformation (stretchability, viscosity) but also fluorescence‐recovery and electroconductivity changes at different cancer‐cell concentrations (104–106 cells mL−1), including distinct strain–pressure responses that can be wirelessly monitored via smartphones. Furthermore, in vivo, experiments suggest that PAA‐MnO2 mineralized hydrogel can be formed in tumor‐bearing mice owing to its excellent ROS‐scavenging activity at the tumor site, as confirmed by SOD2 and gene‐expression analysis. Thus, this unique approach can potentially enable simple and effective cancer detection in future point‐of‐care diagnostics. [ABSTRACT FROM AUTHOR]

Charged double network (DN) hydrogels are widely studied for their desirable mechanical strength and tunable properties. In this work, the influence of polymer concentration on microstructure and properties of agarose/polyacrylic acid DN hydrogels is studied. Agarose, the first network, is a brittle biopolymer, while polyacrylic acid (PAAc) is a weak polyelectrolyte. The microstructure, visualized in liquid environment, displays an agarose scaffold coated and interconnected by PAAc, deviating from the common assumption of an entangled double network. Importantly, the charging of PAAc in the hydrogel is regulated not only by the pH and weak polyelectrolyte effects, but also by the restricted swelling of the double network, and hence, it is an inherent regulation mechanism of charged hydrogels. The interactions between the hydrogel and the ionic environment induce microstructural changes and charging of the double network, impacting surface properties such as topography, stiffness, and adhesion, which are spatially resolved by liquid‐environment atomic force microscopy. The responsiveness of the DN hydrogels significantly depends on both polymer concentrations and ion concentrations. These findings provide insights into the responsive behavior of double network hydrogels and reveal universal mechanisms for charged hydrogels, which can guide the future development of functional soft materials. [ABSTRACT FROM AUTHOR]

Carbopol® is a typical jelly agent belonging to the family of cross-linked polyacrylic acid copolymers. It is largely used in antibacterial gels due to its self-wetting properties. In its pristine physical form, Carbopol® falls under the definition of microplastics, though significant changes could occur once added to hydroalcoholic solvents of the liquid formulations. To date, no life-cycle data regarding the physical state are available for this substance or for other similar polymers of the same chemical class. The aim of the present study was the investigation of the fate of Carbopol®-derived microplastics used in the formulation of typical hand sanitizer gels available in the Italian market, such as Amuchina® X-Germ, along the product life cycle. An experimental model was designed to detect the presence of Carbopol® microparticles from product manufacturing to the final use. FTIR and µ-FTIR were used to detect and characterize solid particles after the optimization of the sample preparation of different experimental matrices. While Carbopol® as such can be classified as a microplastic, in the commercial product, Carbopol® particles were not detected. Ten volunteers used the product according to the instructions reported on the label, and finally they rinsed their hands. Carbopol®-based particles were not detected in the water rinse, indicating that, after usage, the original form of the Carbopol microparticles was not retrieved. The study proposes, for the first time, a simple and comprehensive experimental approach to identify and characterize microplastics in finished products and along the life cycle by simulating their real-life usage. This approach could be also useful to evaluate the release of chemical components into the environment through the use of dermal products. [ABSTRACT FROM AUTHOR]

Using a solid-state technique under low temperature conditions, Er3+/Yb3+ co-doped Bi2Mo2O9 phosphors with different concentrations were prepared, exhibiting excellent green up-conversion luminescence property. A thorough investigation was conducted on the phase structure, optical transition, up-conversion luminescence, and down-shifting luminescence properties of the prepared samples. Bi2Mo2O9: Er3+/Yb3+ phosphors excited at 381, 980, and 1550 nm showed strong green fluorescence together with very faint red emission. The mechanism of up-conversion luminescence and its capacity for temperature sensing were examined under the excitation of various wavelengths. Under 980 nm excitation, the maximal relative and absolute sensitivities were determined to be 1.107%K− 1 and 0.756%K− 1 at 303 K and 513 K, respectively. Furthermore, the Judd-Ofelt intensity parameters of Er3+ in Bi2Mo2O9: Er3+/Yb3+ phosphors were calculated using the diffuse reflectance spectra and fluorescence lifetime of Er3+. In addition, material was combined with polyacrylic acid to make an anti-counterfeiting pattern. The results indicate that Bi2Mo2O9: Er3+/Yb3+ phosphor is an excellent green phosphor with optical temperature measurement function, and it also has certain applications in the field of anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Silica fume (SF) is an essential component in ultra-high-performance concrete (UHPC) to compact the matrix, but the nucleus effect also causes rapid hydration, which results in high heat release and large shrinkage. In this paper, the carboxylic agents, including polyacrylic acid and polycarboxylate superplasticizer, were used to surface modify SF to adjust the activity to mitigate hydration at an early time and to promote continuous hydration for a long period. The surface and dispersion properties of modified SF (MSF), as well as the strength and pore structure of UHPC, were studied, and the stability of the modification was also investigated. The results demonstrated that, after treatment, the carboxylic groups were grafted on the SF surface, the dispersion of SF was improved due to the increased negative pentanal of the particle surface and the steric hindrance effect, the early hydration was delayed about 3–5 h, and the hydration heat release was also mitigated. The compressive strength of UHPC with MSF reached a maximum of 138.7 MPa at 3 days, which decreased about 3.7% more than the plain group, while flexural strength varied insignificantly. More pores and cracks were observed in the matrix with MSF, and the hydration degree was promoted with MSF addition. The grafted group on SF fell off under an alkali environment after 1 h. [ABSTRACT FROM AUTHOR]

Nano-bienzyme conjugates (nano-BECs) for catalysing one-pot reactions can simplify the reaction process and improve the efficiency of biocatalytic reactions. In this work glucose dehydrogenase (GDH) and Candida parapsilosis secondary alcohol dehydrogenase (CpSADH) were immobilised with polyacrylic acid (PAA) to form two types of PAA-based nano-BECs (2-S, 2-P), which achieved in situ regeneration of NADH for the production of chiral alcohols in oil-water biphasic systems, such as the key chiral pharmaceutical intermediate of (S)-1-(3-trifluoromethylphenyl)ethanol ((S)-TMPE). At a substrate concentration of 100 mM 3-trifluoromethylacetophenone (TMAP), the conversion catalyzed by nano BEC was 98.2 % in dipentyl phthalate-phosphate buffer biphasic system. In contrast, the conversion was only 39.5 % and 38.9 % in the PB buffer and 8.4 % and 7.7 % in dipentyl phthalate system. The experiments on kinetic constants demonstrated that the catalytic efficiencies (K cat /K m) of nano-BECs (2-S, 2-P) were enhanced by 6.7-fold and 7-fold, respectively, compared to free CpSADH. Additionally, nano-BECs showed stronger coenzyme regeneration ability. Under optimal reaction conditions, nano-BECs achieved 96.2 % conversion of TMAP to (S)-TMPE in an organic-buffer system with e.e. > 99.6 % at 300 mM substrate concentration. This research expands the potential applications of polymers and proteins, and offers valuable insights into the synergistic effects of PAA on bienzyme catalytic systems in biocatalysis. [Display omitted] • Heterologous expression of Candida parapsilosis secondary alcohol dehydrogenase (CpSADH). • Co-immobilization of glucose dehydrogenase (GDH) and CpSADH to form nano-polymers. • One-pot efficient catalytic carbonyl asymmetric reduction by nano-polymers. • Preparation of (S)-1-(3-trifluoromethylphenyl)ethanol at high substrate concentration. [ABSTRACT FROM AUTHOR]

Hydrogels can relieve wound pain and provide a moist environment for wound healing. Although hydrogels based on natural materials have proven to be biocompatible and biodegradable, their antibacterial and anti-inflammatory properties are not desirable. Natural extracts with antimicrobial and antioxidant properties are becoming increasingly attractive because of their environmentally friendly nature and good biocompatibility. Herein, composite cellulose/silk fibroin/polyacrylic acid hydrogels based on natural materials were fabricated by crosslinking between oxidized cellulose and silk fibroin together with radical polymerization of acrylic acid. The fabricated hydrogels displayed a uniform hierarchical topography with high porosity, as well as good mechanical properties, swelling properties, air permeability and biocompatibility. With the addition of tea polyphenols to natural extracts, the composite hydrogels exhibited significant antimicrobial and antioxidant properties such that they could prevent bacterial infection and relieve wound inflammation in the inflammation stage and could promote the synthesis of extracellular matrix (ECM), angiogenesis, collagenization and re-epithelization during wound healing. The tea polyphenols/cellulose/silk fibroin/polyacrylic acid hydrogels fabricated in this study can accelerate wound healing, demonstrating their great potential for application in wound dressings. [ABSTRACT FROM AUTHOR]

Zn–air batteries (ZABs) are a promising technology; however, their commercialization is limited by challenges, including those occurring in the electrolyte, and thus, gel polymer electrolytes (GPEs) and hydrogels have emerged as substitutes for traditional aqueous electrolytes. In this work, PVA/PAA membranes were synthesized by the solvent casting method and soaked in 6 M KOH to act as GPEs. The thickness of the membrane was modified (50, 100, and 150 μm), and after determining the best thickness, the membrane was modified with synthesized SiO2 nanospheres and multi-walled carbon nanotubes (CNTs). SEM micrographs revealed that the CNTs displayed lengths of tens of micrometers, having a narrow diameter (95 ± 7 nm). In addition, SEM revealed that the SiO2 nanospheres had homogeneous shapes with sizes of 110 ± 10 nm. Physicochemical experiments revealed that SiO2 incorporation at 5 wt.% increased the water uptake of the PVA/PAA membrane from 465% to 525% and the ionic conductivity to 170 mS cm−1. The further addition of 0.5 wt.% CNTs did not impact the water uptake but it promoted a porous structure, increasing the power density and the stability, showing three-times-higher rechargeability than the ZAB operated with the PVA/PAA GPE. [ABSTRACT FROM AUTHOR]

Novel elastomers are made by reaction of hydroxyl‐terminated polyacrylic ester (HyTemp) with polyethylene glycol (PEG, number of ethylene glycol units 1, 3, 6, 9) based cross‐linkers. The influence of the cross‐linker length, the HyTemp/cross‐linker (w/w) ratio and the cross‐linking accelerator trifluoromethanesulfonate scandium salt (ScTFMS) on the structure and the properties of the materials are studied. The cross‐linker length has not influence on the glass transition (Tg) of the products because of the presence of the flexible PEG units that cancels out the cross‐linking effect associated to a shift to higher Tg. A two‐domain structure is seen by the presence of a dual Tg in samples cured with ScTFMS. Mathematical analysis of the modulated differential scanning calorimetry curves offers for the first time the possibility to identify/confirm structural differences in complex three‐dimensional polymeric structures. Scanning electron microscopy and swelling experiments in ethyl acetate respectively reveal an increase in the pore size (1.13 to 5.48 nm) and in the absorption ability of the elastomers cured with different types and quantities of PEG cross‐linker. The new elastomeric materials are exhibiting a rubbery state over a wide temperature range and absorptivity for the potential recovery of pollutants in soil and/or water. [ABSTRACT FROM AUTHOR]

BACKGROUND: Infectious bovine keratoconjunctivitis (IBK; pinkeye) is generally considered to be caused by corneal infections with Moraxella bovis. Previous studies demonstrated that M. bovis cytotoxin-specific mucosal immune responses in the bovine eye can be stimulated by intranasal vaccination with a recombinant M. bovis cytotoxin subunit adjuvanted with polyacrylic acid. METHODS: A randomized controlled field trial (two-arm parallel design with blinding) was conducted in beef steers in Northern California to determine if this vaccine could prevent naturally occurring IBK and/or reduce morbidity rates associated with this disease. Beef steers were vaccinated intranasally on days 0 and 21 with either a recombinant M. bovis cytotoxin subunit adjuvanted with polyacrylic acid (Vaccine group) or adjuvant alone (Control group). Eye examinations were performed on all steers every 7 days for 16 weeks to document the occurrence of IBK and to determine sizes of corneal ulcers. Serum and tear samples were collected on days 0, 42, and 112 from a subset of animals to measure changes in systemic and ocular immune responses to M. bovis cytotoxin. RESULTS: The cumulative proportion of steers that developed IBK after 16 weeks did not differ between groups. Variables related to disease severity were numerically lower in steers that received the experimental vaccine. IBK-affected Vaccine group steers had a significantly lower number of observation weeks with severe ulcers versus Control group steers. Cytotoxin-specific tear IgA was significantly higher in Vaccine group compared to Control group steers on day 112. Conclusion: Although the proportion of animals that developed corneal ulcers associated with IBK did not differ between groups, the lowered metrics of disease severity in vaccinated steers suggests that intranasal vaccination with recombinant M. bovis cytotoxin can reduce the severity of IBK in cattle.

[Display omitted] Flexible electronics have introduced new challenges for efficient human–machine interactions. Hydrogels have emerged as prominent materials for electronic wearable applications due to their exceptional mechanical deformability and lightweight characteristics combined in some cases with conductive properties, and softness. Additionally, bio-interphases require multisensory response to stress, strain, temperature, and self-healing capacity. To mimic these properties, this work developed interpenetrated hydrogel networks composed of chitosan (CHI) and polyacrylic acid (PAA), combined with Fe (III) ions and varying amounts of NMBA (0–0.25 %), to achieve tailored conductivity (0.8–2.5 mS/cm), self-healing, self-standing and mechanical properties (E = 11.7–110 Pa and fracture strain = 64.9–1923 %) suitable for strain sensor applications. The results revealed a significant influence of the restrictive effect on the mobility of uncrosslinked chain segments, caused by Fe ions and NMBA, on the piezoresistance (GF 2.1–1.3) and self-healing capability of the gels. Interestingly, a transparent/turbid transition, driven by microphase separation that is characteristic of systems with high dynamic interactions, was encountered for the first time in these hydrogels. This transition was analyzed in relation to external temperature, water content, pH, and the influence of Fe ions and NMBA. The simultaneous sensitivity of these materials to temperature and pH, along with their piezoresistive and self-healing behaviour, can be highly valuable for multifunctional sensors in a wide range of applications. [ABSTRACT FROM AUTHOR]

In this paper, macroporous high‐entropy spinel oxide (HESO) (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 monoliths were successfully fabricated via a sol–gel method followed by calcination. Appropriate polyacrylic acid and propylene oxide contents allow the formation of three‐dimensional co‐continuous xerogel monoliths, and the water/glycerol ratio controls the macropore size of monoliths. Subsequent calcination achieves the precipitation of HESO (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 with a singular phase and exceptional structural stability. The macroporous HESO (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 demonstrates remarkable performance in the oxygen evolution reaction (OER) with an overpotential of 333 mV at 100 mA cm−2 and a Tafel slope of 43.2 mV dec–1, surpassing that of RuO2 (391 mV) under identical conditions. Furthermore, the catalytic stability of the HESO catalyst remains superior even after 24 h of testing. This process offers a promising avenue for the development of macroporous high‐entropy oxide OER catalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

Background and Objectives: In recent years, the attention of the scientific community has been attracted by cerium(IV) oxide nanoparticles (CeO2 NPs), which demonstrate great potential for use in biomedicine due to their unique biological properties such as antioxidant and antibacterial activity. The development of biomaterials that combine the properties of polymers and the unique characteristics of CeO2 NPs opens up new horizons for applications in biomedicine. A thin layer of polymers preserves the catalytic activity of cerium oxide without blocking the path of electronic charge transfer on the surface of nanoparticles. The relevance of the development of CeO2 NPs with a polymer shell lies in the fact that polymers can bind to various medicinal and bioactive substances, becoming drug carriers. This work describes the preparation of CeO2 NPs with various polymers in order to study how the composition and structure of the polymer affect the size and charge of the resulting nanoparticles. The variability of the properties of CeO2 NPs will make it possible to test them for the encapsulation of other substances, including drugs, in order to identify optimal polymers. Materials and Methods: Cerium(III) nitrate hexahydrate Ce(NO3)3 · 6H2O was used as a precursor for the synthesis of CeO2 NPs. Four different polymers were used for the syntheses: polyacrylic acid (PAA), polyethylene glycol (PEG), poly(isobutylene-alt-maleic anhydride) (PIMA). The synthesis was carried out in ammonium hydroxide (28–30%). CeO2 NPs with a polymer shell were obtained by chemical deposition. Polymer solutions were prepared and mixed with a 1 M solution of Ce(NO3)3. With continuous stirring, the mixture was added to the ammonium hydroxide solution, after which ethanol was added and left under stirring for 24 hours at room temperature. Results: We have presented the synthesis of cerium oxide nanoparticles in the presence of polymers of various compositions and molecular weights to study their effect on the structure and size of nanoparticles. During the synthesis, it has been revealed that the optimal concentration of cerium(III) nitrate for syntheses is 1 M. The influence of the environment on the possible agglomeration of nanoparticles during purification and further storage has been studied. The best media for storing and purifying nanoparticles are water and phosphate-buffered saline. The size and morphology of the resulting polymer-coated CeO2 NPs have been studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scattering (DLS). TEM images show nanocrystals measuring about 10 nm in all four samples. SEM images show the presence of particles with a size of about 20–30 nm in all four samples. DLS analysis has shown that the smallest particles were formed with polyacrylic acid and poly(isobutylene-alt-maleic anhydride). Conclusions: The results of the study have demonstrated that for the synthesis of CeO2 NPs with a polymer coating it is better to use PAA and PIMA polymers since smaller particles are formed. It has been found that it is optimal to use 1 M Ce(NO3)3 for syntheses, and the best media for purification and storage of CeO2 NPs are water and FSB.

In this study, hydrogels of polyacrylic acid (PAA) were synthesised using free radical polymerization of acrylic acid. This process was carried out in an aqueous medium in the existence of ammonium persulfate (APS) acting as an initiator, and N, N'- methylene bisacrylamide (MBA), which is used as a crosslinker. There were four different acrylic acid hydrogel formulations made, and each had a different crosslinker concentration that varied from 0.5 to 2.0 mol% MBA. The next step includes the co-precipitation of PAA7 with iron oxide magnetite nanoparticles (PAA7/Fe3O4) for recover the hydrogel from batch mode using a magnetic field once Ultracidin pesticide has been absorbed from aqueous solutions. The adsorbent was characterized by FTIR, VSM, and XRD. The Ultracidin adsorption from an aqueous solution was studied by varying a number of parameters, including pH, contact time, temperature, adsorbent dose, and adsorbate concentration. Best adsorption efficiency was obtained at a temperature of 25°C, 60 minutes of contact time at pH 3, with 50 mg L-1, of initial pesticide concentration, and 4 g L-1 adsorbent dose. Several models were used to examine the adsorption kinetics of pesticide onto the adsorbent (PAA7/Fe3O4 NPs). The best effect showed that the pseudo second order model correlates with the experimental data. To determine the ideal adsorption capacity of the adsorbent, Langmuir, Freundlich, and Tempkin adsorption isotherms were utilized. Langmuir- model demonstrated a fitter than other models. The outcomes show that Ultracidin can be successfully removed from polluted water using (PAA7/Fe3O4 NPs) composite.

AbstractWe use the dynamic light scattering technique (DLS) to study the dynamic behavior of complex constituted by weakly charged microemulsion in the presence of polyelectrolyte. We investigated the impact of adding oppositely charged polyacid (PAA), which is a pH-dependent polyelectrolyte, on the dynamics of charged microemulsion nanodroplets in an acidic medium at pH = 4.5 when the polyacrylic acid are partially charged. In a diluted regime, two diffusive relaxation modes are seen when adding (upon addition) the polyacrylic acid PAA to the microemulsion nanodroplets due to collective diffusion and self-diffusion fluctuations. In the concentrated regime, we observed three diffusive relaxation modes when charged microemulsion nanodroplets complexed with oppositely charged polyacrylic acid. We attribute the two first relaxation modes to the collective diffusion (fluctuation of concentration) and self-diffusion of the microemulsion nanodroplets. The third mode which is a slower relaxation mode; we attribute this relaxation process to the motion of the network formed by the polyacid PAA and microemulsion nanodroplets, or “breathing mode” of the network. [ABSTRACT FROM AUTHOR]

Infectious bone defects are one of the thorny problems faced by orthopedists. Developing prosthetic materials with antimicrobial osteogenic features is a key solution. Biodegradable Polyacrylic acid (PAA)-based hydrogels have gained attention for their exceptional qualities. However, the influence of zinc ions on PAA-based mineralized hydrogels remains understudied. In this paper, Poly (acrylic acid)-calcium-zinc (PA-CZ) biomineralized hydrogel was prepared through ionic cross-linking and biomineralization. In vitro bacterial and cell tests demonstrated the hydrogel's exceptional biocompatibility, antibacterial, and osteogenic traits, along with good mechanical strength. The PA-CZ mineralized hydrogel lays the foundation for developing orthopedic implants with antimicrobial osteogenic features and offers a promising approach for treating infected bone defects. [ABSTRACT FROM AUTHOR]

In this paper, N-vinylpyrrolidone was copolymerized with acrylic acid and itaconic acid by free radical polymerization, and a series of polyacrylic acid-co-itaconic acid-co-N-vinylpyrrolidone (PAIN) dispersants with different pyrrolidone ligand contents were synthesized and characterized. Then, the cobalt blue nano-pigment slurry (20 wt%) was prepared through a water-based grinding method, and the optimum grinding technology was explored and determined as follows: PAIN2 as a dispersant, a dispersant dosage of 10 wt%, and a grinding time of 480 min. According to this optimum grinding technology, the prepared pigment slurry had a significantly decreased agglomeration, the D90 of which was 82 nm, and separately increased to 130 nm and 150 nm after heat storage for 3 and 7 days, exhibiting excellent heat storage stability. Additionally, its TSI value was also the lowest (1.9%), indicating good dispersion stability. The QCM and adorption capacity measuring results showed PAIN2 had a larger adsorption capacity, and the formed adsorption layer had a higher rigidity and was not easy to fall off. This was caused by both the interaction of carboxyl groups and the pyrrolidone ligand (strong coordination interaction) in PAIN2 with cobalt blue. The XPS and FT–IR measurements further proved the above-mentioned adsorption mechanism. [ABSTRACT FROM AUTHOR]

AbstractConventional wound dressings used in trauma treatment have a single function and insufficient adaptability to the wound environment, making it difficult to meet the complex demands of the healing process. Stimuli-responsive hydrogels can respond specifically to the particular environment of the wound area and realize on-demand responsive release by loading active substances, which can effectively promote wound healing. In this paper, BC/PAA-pH responsive hydrogels (BPPRHs) were prepared by graft copolymerization of acrylic acid (AA) to the end of the molecular chain of bacterial cellulose (BC) network structure. Antibacterial pH-responsive ‘smart’ dressings were prepared by loading curcumin (Cur) onto the hydrogels. Surface morphology, chemical groups, crystallinity, rheological, and mechanical properties of BPPRHs were analyzed by different characterization methods. The drug release behavior under different physiological conditions and bacteriostatic properties of BPPRH-Cur dressings were also investigated. The results of structural characterization and performance studies show that the hydrogel has a three-dimensional mesh structure and can respond to wound pH in a ‘smart’ drug release capacity. The drug release behavior of the BPPRH-Cur dressings under different environmental conditions conformed to the logistic and Weibull kinetic models. BPPRH-Cur displayed good antimicrobial activity against common pathogens of wound infections such as E. coli, S. aureus, and P. aeruginosa by destroying the cell membrane and lysing the bacterial cells. This study lays the foundation for the development of new pharmaceutical dressings with positive health, economic and social benefits. [ABSTRACT FROM AUTHOR]

The combination of hydrogel and fertilizer as slow release fertilizer hydrogel (SRFH) has become one of the most promising materials to overcome the shortcomings of conventional fertilizer by decreasing fertilizer loss rate, supplying nutrients sustainably, and lowering the frequency of irrigation. The hydrogel based on carboxymethyl cellulose (CMC) and polyacrylic acid (PAA) (CMC/PAA) was synthesized. All materials, Vinasse, hydrogel (CMC/PAA) and (Vinasse/CMC-PAA) were characterized by FTIR, XRD, and SEM. The formed hydrogel was applied to control the salinity of Vinasse to use it as a cheap and economical fertilizer. The results showed that using the prepared hydrogel with Vinasse (V/CMC-PAA) as a slow-release organic fertilizer decreased the EC value through the first six hours from 1.77 to 0.35 mmohs/cm. Also, using V/CMC-PAA can control and keep the potassium as fertilizer for 50 days. The productivity per feddan from the sugar cane crop increased by about 15%, and the number of irrigations decreased from 5 to 4 times. [ABSTRACT FROM AUTHOR]

Silicon (Si) and silicon/graphite (Si/Gr) composite anodes are promising candidates due to their high theoretical capacity, low operating potential and natural abundance for high energy density Li‐ion batteries. Green electrode production, eliminating organic volatile solvents require advancement of aqueous electrodes. Engineering the binder plays a critical role for improving waterborne electrodes. Lithium substituted polyacrylic acid LiPAA has been demonstrated as a promising binder for Si/Gr anodes and for Ni‐rich cathodes in different cell configurations. LiPAA is utilized to minimize the volume expansion during cycling for Si/Gr anodes. LiPAA is formed in situ during cathode slurry preparation to regulate the pH and dimmish the Li loss. Using advanced characterization techniques, we investigated the slurries, electrodes, and active material reaction with LiPAA and its effect to the cycling performance. Our results indicate that the performance of high Si containing anode is limited by the amount of Si in the electrode. The failure mechanism with respect to high Si content was studied thoroughly. Aqueous processed cathodes with LiPAA binder in combination with Si anodes outperformed NMP based cathodes. Hence, LiPAA was successfully utilized as an active binder for both a high Si containing anode and for a Ni rich cathode. [ABSTRACT FROM AUTHOR]

Mastering electrodes' formulations is a complex and tedious task, because for each composition of electroactive material(s) it is necessary to adjust the inactive additives nature and content to optimize battery performance. In this direction, the amount of binder is proposed to be adjusted to the surface developed by all of the powders involved in the composition of the electrode, i.e., the electroactive materials and electronic conductive additives. This concept, introduces here as binder‐to‐powders coverage ratio, relies upon the micromechanical models developed in the field of polymer‐based composite materials. The validity of this new electrode formulation parameter is shown here for two different SiOx/Graphite blends, which differ in the type of graphite, and for blends of two different binders, polyacrylic acid and styrene−butadiene rubber. At the optimal coverage ratio, a satisfactory capacity retention is obtained in full cell with an ethylene carbonate free and fluoroethylene carbonate rich electrolyte. [ABSTRACT FROM AUTHOR]

This work investigated the flocculation of sub-micron titanium dioxide (TiO2) by polyacrylic acids (PAAs), with a focus on studying the correlation between the PAAs adsorption conformation and the flocculation efficiency/floc property. The adsorption analysis of PAAs on the TiO2 surface was studied by attenuated total reflection Fourier transform infrared, Raman, X-ray photoelectron spectroscopy, CHNS elemental analyzer coupled with quartz crystal microbalance with dissipation monitoring. Adsorption densities were fitted using Langmuir and Freundlich isotherm models. The flocculation process of TiO2 by PAAs of different molecular weights (MWs) was monitored in real-time by a photometric dispersion analyser, and the floc structure was studied by scanning electron microscope. The results showed that the adsorption of PAAs followed the Langmuir isotherm, and formed monolayer adsorption on the TiO2 surface regardless of MWs through hydrogen and bidentate chelating chemical bonds. The thickness of adsorption layer increased with increasing MW, which could promote floc size by providing molecular "bridges"; but impeded the flocculation rate. For sub-micron particles, polyacrylic acid with a medium MW (512 kDa) was the optimum polymer owing to obtaining the fastest flocculation rate and relatively dense flocs in this work. PAA with high MW resulted in larger flocs with greater porosity, whereas the low MW PAA can only generate smaller flocs with a slower flocculation rate. [ABSTRACT FROM AUTHOR]

This manuscript describes the synthesis of green long afterglow nanophosphors SrAl2O4:Eu2+, Nd3+ using the combustion process. The study encompassed the photoluminescence behavior, elemental composition, chemical valence, morphology, and phase purity of SrAl2O4:Eu2+, Nd3+ nanoparticles. The results demonstrate that after introducing Eu2+ into the matrix lattice, it exhibits an emission band centered at 508 nm when excited by 365 nm ultraviolet light, which is induced by the 4f65d1→4f7 transition of Eu2+ ions. The optimal doping concentrations of Eu2+ and Nd3+ were determined to be 2% and 1%, respectively. Based on X-ray diffraction (XRD) analysis, we have found that the physical phase was not altered by the doping of Eu2+ and Nd3+. Then, we analyzed and compared the quantum yield, fluorescence lifetime, and afterglow decay time of the samples; the co-doped ion Nd3+ itself does not emit light, but it can serve as an electron trap center to collect a portion of the electrons produced by the excitation of Eu2+, which gradually returns to the ground state after the excitation stops, generating an afterglow luminescence of about 15 s. The quantum yields of SrAl2O4:Eu2+ and SrAl2O4:Eu2+, Nd3+ phosphors were 41.59% and 10.10% and the fluorescence lifetimes were 404 ns and 76 ns, respectively. In addition, the Eg value of 4.98 eV was determined based on the diffuse reflectance spectra of the material, which closely matches the calculated bandgap value of SrAl2O4. The material can be combined with polyacrylic acid to create optical anti-counterfeiting ink, and the butterfly and ladybug patterns were effectively printed through screen printing; this demonstrates the potential use of phosphor in the realm of anti-counterfeiting printing. [ABSTRACT FROM AUTHOR]

In vitro alternative therapy of human epidermoid squamous carcinoma (A431) by superparamagnetic hyperthermia (SPMHT) using Fe3O4 (magnetite) superparamagnetic nanoparticles (SPIONs) with an average diameter of 15.8 nm, bioconjugated with hydroxypropyl gamma-cyclodextrins (HP-γ-CDs) by means of polyacrylic acid (PAA) biopolymer, is presented in this paper. The therapy was carried out at a temperature of 43 °C for 30 min using the concentrations of Fe3O4 ferrimagnetic nanoparticles from nanobioconjugates of 1, 5, and 10 mg/mL nanoparticles in cell suspension, which were previously found by us to be non-toxic for healthy cells (cell viabilities close to 100%), according to ISO standards (cell viability must be greater than 70%). The temperature for the in vitro therapy was obtained by the safe application (without exceeding the biological limit and cellular damage) of an alternating magnetic field with a frequency of 312.4 kHz and amplitudes of 168, 208, and 370 G, depending on the concentration of the magnetic nanoparticles. The optimal concentration of magnetic nanoparticles in suspension was found experimentally. The results obtained after the treatment show its high effectiveness in destroying the A431 tumor cells, up to 83%, with the possibility of increasing even more, which demonstrates the viability of the SPMHT method with Fe3O4-PAA–(HP-γ-CDs) nanobioconjugates for human squamous cancer therapy. [ABSTRACT FROM AUTHOR]

Uranyl ion (UO22+) is both radiotoxic and chemically toxic, which has harmful effects on the ecological environment and human health. This work presents a novel material called two-dimensional photonic crystal polyacrylic acid hydrogel (2D-PCPAAH), which contains massive carboxyl groups that can bind to UO22+ by strong coordination interaction. UO22+ can be combined with multiple ligand groups, causing the shrinkage of the 2D-PCPAAH which results in a reduction in particle spacing and a color change. Via measuring the Debye diffraction ring diameter using a ruler, the particle spacing can be easily obtained and the UO22+ concentration can be determined. [ABSTRACT FROM AUTHOR]

This study investigates the influence of two types of binders (aqueous and nonaqueous) on the LiFePO4 (LFP) electrode processing and its electrochemical properties. Specifically, polyvinylidene fluoride (PVDF) and polyacrylic acid (PAA) were dissolved in NMP (N‐methyl‐2‐pyrrolidone) or the aqueous solvent (H2O) at varying mass ratios of 5%, 10%, and 15%. Binder durability and inertness were assessed by immersing prepared LFP electrodes in an electrolyte comprising 1.0 M LiPF6 in EC:DEC:DMC (1:1:1 in vol%). Notably, PVDF/NMP 10% and PAA/H2O 10%‐based electrodes displayed good durability without peeling. Electrochemical characteristics were evaluated through cycling voltammetry and galvanostatic cycling with potential limitation. The PAA/H2O 10%‐based‐LFP electrode exhibited a specific capacity of ~148.9 mAh g−1 with a Coulombic efficiency (CE) of around 97.27%, surpassing PVDF/NMP 10%. The graphite||PAA/H2O 10%‐based‐LFP electrode in a full cell demonstrated higher capacity and superior retention after 30 cycles. In a pouch cell (6 cm × 4 cm), utilizing graphite||LFP with PAA/H2O 10%, a capacity of 25.5 mAh was achieved, maintaining 93% capacity with a CE of about 99% after 30 cycles at a rate of 0.1C. [ABSTRACT FROM AUTHOR]

Silicon is considered as a promising candidate for anode materials due to its ultrahigh theoretical capacity and natural abundance. However, the commercialization is severely hampered by the large strain and short cycle life. Herein, we have synthesized a reversible polyelectrolyte/polyzwitterion coacervate framework to achieve high‐performance silicon anodes with high initial Coulombic efficiency (ICE) and stable cyclability. Such coacervate framework is formed via in‐situ free radical polymerization of zwitterionic 2‐methacryloyloxy ethyl phosphorylcholine (MPC) with polyacrylic acid (pAA) during heating the slurry. The resulting pAA/pMPC coacervate framework presents excellent adhesion, thermal stability, and negligible swelling in the electrolyte. Comparing with pAA, pAA/pMPC0.1 coacervate framework binder exhibits superior performance during charge/discharge. The ICE is improved from 84.41 %, to 87.61 %. After 250 cycles, the specific capacity of pAA/pMPC0.1 silicon anode is 1678 mAh g−1 with a retention of 78 % while the pAA silicon anode completely failed after less than 200 cycles. Such improvement is ascribed to the structural integrity of the electrode endowed by the self‐healing ability of pAA/pMPC coacervate framework. This work not only offers a feasible method to in‐situ construct coacervate framework with self‐healing capability to achieve high‐performance silicon anodes but also a compatible electrode preparation process for other high‐capacity materials. [ABSTRACT FROM AUTHOR]

Silicon, serving as an anode material of Li‐ion batteries, offers a theoretical capacity significantly higher than graphite, but its practical application is hindered by poor conductivity, low lithium ion diffusivity, and severe volumetric expansion. Here, a simple and eco‐friendly methodology is proposed to synthesize precisely prelithiated polyacrylic acid binder, optimizing the interface between the binder and micron Si particles. The incorporation of these binders not only mitigates the detrimental effects of volumetric expansion but also enhances mechanical strength, and ionic conductivity of the anode, significantly improving the initial Coulombic efficiency (ICE), cycling stability, and rate performance of micron‐sized Si anodes. This study not only highlights the potential of prelithiated binders in overcoming the limitations of micron‐sized Si anodes but also sets a new benchmark for the development of high‐capacity, eco‐friendly Li‐ion batteries. [ABSTRACT FROM AUTHOR]

AbstractGellan Gum (GG) grafted poly-acrylic acid (GG-g-pAAc) hydrogels of different composition were synthesized by changing the concentration of GG through free radical polymerization. The hydrogels were characterized through SEM, TGA, and FTIR. The FTIR spectra confirmed the grafting of GG into the network of polyacrylic acid and evidenced the GG-g-pAAc formation. The rough surface nature of the hydrogels was elaborated through SEM analysis provided the information about the materials to be utilized for removal purpose. The thermal stability was confirmed by TGA analysis and the hydrogels were found stable upto a high temperature range. With an efficiency of 96%, Basic Orange-2 dye (BO-2) was successfully removed from wastewater using synthesized hydrogels as an adsorbent. The adsorption parameters were calculated using a number of different kinetic models. According to the findings, the pseudo-second order kinetics model best suited to the kinetics data, while the Langmuir isotherm provided the most comprehensive explanation of the process of adsorption. BO-2 was removed to the greatest extent (257.5 mg/g). Additionally, the results showed that the adsorption process on synthesized hydrogels was exothermic with values of ΔH = −13.2, −219.4 and −12.9 kJ/mol for pAAc, 10%GG-g-pAAc, and 20%GG-g-pAAc respectively. The adsorption process is spontaneous, with negative values of ΔG = −8.2, −214.4 and −7.947 kJ/mol for pAAc, 10%GG-g-pAAc and 20%GG-g-pAAc at 293K, respectively. The adsorption process on synthesized hydrogels showed no dis-orderness with negative values of ΔS = −17.2, −461.16 and −16.42 kJ/mol for pAAc, 10%GG-g-pAAc and 20%GG-g-pAAc, respectively. [ABSTRACT FROM AUTHOR]

In this study, polyacrylic acid hydrogels were prepared by modulating the cross-linking agent mass ratio using UV and heat curing methods. The structures and properties of the hydrogels were characterized and analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The results showed that the mechanical properties of the hydrogels prepared through UV curing were better than those prepared through heat curing. The maximum mechanical tensile strength of 139 kPa was achieved at a cross-linking agent mass ratio of 3.85% with 20 min of UV curing, and the maximum mechanical compressive strength of 0.16 MPa was achieved at a cross-linking agent mass ratio of 2.91% with 20 min of UV curing. However, the hydrogels prepared by heat curing had a higher tensile strength than those prepared using the heat curing method. In addition, the thermally cured hydrogels had higher water absorption and adsorption properties. Moreover, the PAA hydrogels prepared at cross-linking agent mass ratios of 1.91 and 2.91% with 2 h of the heat curing method had the best swelling properties. Moreover, the increase in the cross-linker mass concentration led to a decrease in the pore size and porosity and to a more compact structure. [ABSTRACT FROM AUTHOR]

This paper prepares a new kind of anthocyanins/shikonin/polyacrylic‐starch porous sheet with high acid or alkaline gas responsiveness, the high pH sensitivity Lycium ruthenium anthocyanins/shikonin is used as the pigment indicator, and the polyacrylic acid‐starch with cross‐linking interpenetrating and porous structure is used as the carrier, which is prepared by cross‐linking and monomer polymerization methods. Then the microstructure, thermal stability, and pH responsiveness of the anthocyanins/shikonin/polyacrylic‐starch porous sheet are characterized. It is applied to monitor the freshness of pork and shrimp finally. [ABSTRACT FROM AUTHOR]

Manufacturing intricately controlled, hierarchically distributed structures poses significant fabrication challenges, but is crucial for enhancing functionality in synthetic systems. A 3D printing technique combining advective assembly with rotational direct ink writing is developed and exploited to build topologically complex, multimaterial structures with high precision. A modular advective assembler printhead is fabricated and employed in the process. This flow‐structuring device is designed with a complex network of internal channels that patterns flowing hydrogel‐based inks, creating multi‐layered filaments whose structures go well beyond conventional nozzle shape and size limitations. The composite filaments are extruded into a rotating support bath of Polyacrylic acid microgels. The rheology of the inks and support bath are critical to maintain print fidelity and integrity, and are characterized by linear and nonlinear bulk rheometry. Optimization of the materials creates a platform where curvilinear, multimaterial architectures are constructed without being constrained to slicing across X, Y, and Z axes. The versatility of this manufacturing platform is demonstrated by printing helical structures that undergo swelling‐induced actuation. This processing method has the potential to significantly enhance additive manufacturing by enabling the production of intricate, multiscale composite structures with broad applicability in fields such as bioengineering, soft robotics, and functional composite materials. [ABSTRACT FROM AUTHOR]

In this work, the fabrication and characterization of the nanocomposite hydrogel, as a solid electrode in electrochemical cell and gel electrolyte material using Indium titanium oxide/polyethylene terephthalate (ITO/PET) flexible substrate for double-layer supercapacitors have been reported. The nanocomposite hydrogel composed of Arabic gum (AG), Acrylic acid (AA), reduced graphene oxide (RGO), and silver nanoparticles (AgNPs) was fabricated via a physical cross-linked polymerization reaction, in which the ascorbic acid was used as a reducing agent to generate AgNPs and to convert Graphene oxide (GO) to RGO during the polymerization reaction. The morphology and structural characteristics of nanocomposite hydrogel were investigated using atomic force microscopy (AFM), scanning electron microscope (SEM), Fourier transfer infrared (FTIR), and X-ray fluorescence (XRF). Additionally, the effect of RGO and AgNPs on hydrogel stability was assessed through Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), while its mechanical properties were studied using the nanoindentation test. Electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were also conducted to study the electrochemical properties of the prepared hydrogel. The effects of AgNPs, RGO, and water content were all considered in the study of supercapacitor performance. The microstructural tests showed that the nanocomposite hydrogel has a relatively high swelling rate, which has a crucial effect on the capacitance. Furthermore, the effects of increasing AgNP concentration and water content in the hydrogel matrix showed a significant improvement in its electrochemical performance, compared with that for Arabic gum poly acrylic acid (AGPAA) hydrogel itself, were the specific capacitance exhibited a significant enhancement, converting from a low value to a substantially higher capacitance value. Moreover, when the nanocomposite hydrogel was used as the working electrode in an electrochemical cell with a hydrochloric acid (HCl) electrolyte solution, it exhibited good electrode performance. Additionally, using (ITO/PET) as a flexible substrate for nanocomposite hydrogel shows an improvement in their suitability for supercapacitor applications. Therefore, it is suggested that the fabricated hydrogel supercapacitor has potential applications in the field of renewable and clean energy harvesting. Supplementary Material Supplementary Material File [ABSTRACT FROM AUTHOR]

The presence of microplastics (MP) in the organs of five fish species caught in the freshwater reservoirs of northern Poland was evaluated. Gills, liver, and digestive tracts of several commercial fish species such as common perch, silver Prussian carp, roach, and rainbow trout were tested to assess MP uptake due to their high population size as well as they play significant role as biomonitors. Since the mentioned species are gladly consumed they can be considered as a source of MP for humans. MP items were identified in all fish species. The highest contribution of MP was observed in predatory fish such as rainbow trout and perch. None of the correlations between MP abundance and fish body size. The number of items per individual fish ranged from 1 to 12, with an average of 1.78. Among the investigated MP shapes two types were found: fibers (56 %) and particles (44 %). MP were observed in different organs, such as the gills (50 %), liver (11 %), and digestive tract (39 %). The most dominant color observed was blue (58 %). The dominant size range was 1–5 mm (42 %), and 0.1–0.5 mm (42 %) respectively. The FT-IR characterization revealed the presence of polymers predominantly containing polyethylene, polypropylene, polyacrylic acid, cellophane, and polystyrene. [ABSTRACT FROM AUTHOR]

This research describes the swelling behavior of cellulose nanocrystal-graft-polyacrylic acid/polyvinyl alcohol (CNC-g-PAA/PVA) hydrogels produced via a semi-interpenetrating network (semi-IPN) approach. To improve the dispersion of cellulose nanocrystals (CNCs) in the hydrogel system, the CNCs were embedded into the PAA polymer structure via grafting with AA monomers and polymerization processes. The produced CNC-g-PAA was further developed into a semi-IPN system with polyvinyl alcohol (PVA) to study the effect of CNC content on the water absorption and retention properties. The physical and chemical properties of the semi-IPN hydrogels were characterized using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and rheometer. The data revealed that an increased CNC content significantly improved the swelling ratio and swelling kinetics of the hydrogels at room temperature. Moreover, a higher pH and temperature also enhanced the swelling performance of the hydrogels. These improvements demonstrate the potential utility of CNC-g-PAA/PVA hydrogels in agricultural and horticultural applications. [ABSTRACT FROM AUTHOR]

Glass ionomer cement (GIC) is composed of anionic polyacrylic acid and a silica-based inorganic powder. GIC is used as a filling material in the decayed cavity of the tooth; therefore, compatibility with the tooth tissue is essential. In the present study, we aimed to improve the histocompatibility of GIC by introducing nano-hydroxyapatite (nHA), a component of teeth, into a silica-based inorganic powder. CFAS-nHA was prepared by chemically bonding nanorod hydroxyapatite (nHA) to the surface of calciumfluoroaluminosilicate (CFAS). The synthesis of CFAS-nHA was confirmed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The prepared CFAS-nHA was mixed with polyacrylic acid and cured to prepare GIC containing nHA (GIC-nHA). Cytocompatibility tests of GIC-nHA and GIC were performed using osteoblasts. Osteoblast activity and bone formation ability were superior after GIC-nHA treatment than after control GIC treatment. This enhanced histocompatibility is believed to be due to the improvement of the biological activity of osteoblasts induced by the HA introduced into the GIC. Therefore, to enhance its compatibility with dental tissues, GIC could be manufactured by chemically bonding nHA to the surface of GI inorganic powder. [ABSTRACT FROM AUTHOR]

Hollow silica nanoparticles (HSNPs) have hygroscopic properties because of their high specific surface area and surface hydroxyl groups. However, compared with other hygroscopic materials, their hygroscopic properties are relatively weak, which limits the further application of HSNPs. One feasible method to enhance their hygroscopic properties is by combining highly hygroscopic materials with hollow silica nanoparticles. To take advantage of the high hygroscopicity of polyacrylic acid (PAA) when combined with the high specific surface area of the hollow particles, PAA was coated on the inner and outer surfaces of the silica shell of the nanoparticles in this study to prepare hollow nanoparticles with a PAA/silica/PAA multilayer structure. The size of the PAA/silica/PAA multi-layer nanoparticles is about 85 nm, and the shell thickness is 25 nm. The specific surface area of the multi-layer nanoparticles is 58 m2/g. The water vapor adsorption capacity of multi-layer structure hollow nanoparticles was increased by 160% compared with the HSNPs (increased from 45.9 cm3/m2 to 109.1 cm3/m2). Meanwhile, at the same content of PAA, the PAA/silica/PAA-structured particles will adsorb 9% more water vapor than the PAA/silica-structured particles. This indicates that the high specific surface area structure of the hollow particles will enhance the adsorption ability of PAA toward water vapor. This novel structure of PAA-HSNPs is expected to be used as a humidity-regulating material for filler in environmental and architectural applications. [ABSTRACT FROM AUTHOR]

Creating bionic intelligent robotic systems that emulate human‐like skin perception presents a considerable scientific challenge. This study introduces a multifunctional bionic electronic skin (e‐skin) made from polyacrylic acid ionogel (PAIG), designed to detect human motion signals and transmit them to robotic systems for recognition and classification. The PAIG is synthesized using a suspension of liquid metal and graphene oxide nanosheets as initiators and cross‐linkers. The resulting PAIGs demonstrate excellent mechanical properties, resistance to freezing and drying, and self‐healing capabilities. Functionally, the PAIG effectively captures human motion signals through electromechanical sensing. Furthermore, a bionic intelligent sorting robot system is developed by integrating the PAIG‐based e‐skin with a robotic manipulator. This system leverages its ability to detect frictional electrical signals, enabling precise identification and sorting of materials. The innovations presented in this study hold significant potential for applications in artificial intelligence, rehabilitation training, and intelligent classification systems. [ABSTRACT FROM AUTHOR]

Due to their ability to adapt to subtle changes in response to various external and internal stimuli, smart hydrogels have become increasingly popular in research and industry. However, many currently available hydrogels suffer from poor processability and inferior mechanical properties. For example, the preparation of a hydrogel network that can be subjected to melt processing and electrospinning is challenging. Herein, a series of mechanically strong, shape‐memory hydrogels based on polyacrylic acid (PAAc) chains containing 20–50 mol% of crystallizable n‐octadecylacrylate (C18A) segments are prepared by an organosolv method followed by in situ physical cross‐linking via hydrophobic interactions. The hydrogels exhibit a reversible strong to weak gel transition at 50–60 °C and can be melt‐processed at 60–100 °C, depending on the molar fraction of C18A. Additionally, the hydrogels can be dissolved in chloroform/ethanol mixture to form a viscous solution, which can then be used to produce a nanofibrous network by electrospinning. Effects of polymer concentration, volume ratio of solvents, and mole fraction of C18A on electrospinning are investigated to produce smooth, uniform nanofibers with small fiber diameter. The produced nanofibers, while maintaining their chemical structure, show significantly improved water adsorption capacity, enhanced mechanical properties, and fast shape‐memory performance. [ABSTRACT FROM AUTHOR]

Polymer composites offer numerous benefits, including low cost, easy processability, and diverse applications. In this work, we fabricated a composite material with high thermal conductivity and electromagnetic interference (EMI) shielding performance using EGaIn, a liquid metal (referred to as LM in this paper), MXene (MX), and expanded graphite (EG) as multifunctional fillers, along with polyacrylic acid (PAA). LM was used to exfoliate MX under the effect of shear force, which not only reduced the size of MX but also increased the aspect ratio of the 2D‐structured MX. MX was filled into the pores of EG to make a heat transfer path, thereby enhancing its thermal conductivity, mechanical properties, and EMI SE properties. LM served as the initiator of free‐radical polymerization to convert acrylic acid (AA) into PAA. Finally, the LMMX/EG/PAA composite was hot‐pressed to make the heat‐transfer path dense. As a result, the LMMX/EG/PAA composite exhibited a thermal conductivity of 1.88 W/m·K and an EMI shielding effect of 52 dB. [ABSTRACT FROM AUTHOR]