Search

Supramolecular polymer networks exhibit unique and tunable thermodynamic and dynamic properties that are attractive for a wide array of applications, such as adhesives, rheology modifiers, and compatibilizers. Coherent states (CS) field theories have emerged as a powerful approach for describing the possibly infinite reaction products that result from associating polymers. Up to this point, CS theories have focused on relatively simple polymer architectures. In this work, we develop an extension of the CS framework to study polymers with reversible bonds distributed along the polymer backbone, opening a broad array of new materials that can be studied with theoretical methods. We use this framework to discern the role of reactive site placement on sol–gel phase behavior, including the prediction of a microstructured gel phase that has not been reported for neutral polymer gels. Our results highlight the subtleties of thermodynamics in supramolecular polymers and the necessity for theories that capture them. [ABSTRACT FROM AUTHOR]

The elasticity of polymer networks, formed by cross-linking high molecular mass polymers in the melt state and then swollen by a solvent, involves contributions from both the presence of cross-link network junctions and the interchain interactions associated with the combined effect of excluded volume interactions and topological constraints that become modified when the network is swollen. We test the capacity of the previously developed localization model of rubber elasticity, a mean field "tube model," to describe changes in elasticity observed in classical experimental studies of the mechanical properties of this type of network. In order to obtain a satisfactory comparison to the experiments, it was found to be necessary to account for the independently observed tendency of the network junctions to become localized in the network with appreciable swelling, as well as the interchain interactions emphasized in previous discussions of the localization model. [ABSTRACT FROM AUTHOR]

Hydrogen-bond networks in associating fluids can be extremely robust and characterize the topological properties of the liquid phase, as in the case of water, over its whole domain of stability and beyond. Here, we report on molecular dynamics simulations of hydrogen fluoride (HF), one of the strongest hydrogen-bonding molecules. HF has more limited connectivity than water but can still create long, dynamic chains, setting it apart from most other small molecular liquids. Our simulation results provide robust evidence of a second-order percolation transition of HF's hydrogen bond network occurring below the critical point. This behavior is remarkable as it underlines the presence of two different cohesive mechanisms in liquid HF, one at low temperatures characterized by a spanning network of long, entangled hydrogen-bonded polymers, as opposed to short oligomers bound by the dispersion interaction above the percolation threshold. This second-order phase transition underlines the presence of marked structural heterogeneity in the fluid, which we found in the form of two liquid populations with distinct local densities. [ABSTRACT FROM AUTHOR]

Designing homogeneous networks is considered one typical strategy for solving the problem of strength and toughness conflict of polymer network materials. Experimentalists have proposed the hypothesis of obtaining a structurally homogeneous hydrogel by crosslinking tetra-armed polymers, whose homogeneity was claimed to be verified by scattering characterization and other methods. Nevertheless, it is highly desirable to further evaluate this issue from other perspectives. In this study, a coarse-grained molecular dynamics simulation coupled with a stochastic reaction model is applied to reveal the topological structure of a polymer network synthesized by tetra-armed monomers as precursors. Two different scenarios, distinguished by whether internal cross-linking is allowed, are considered. We introduce the Dijkstra algorithm from graph theory to precisely characterize the network structure. The microscopic features of the network structure, e.g., loop size, dispersity, and size distribution, are obtained via the Dijkstra algorithm. By comparing the two reaction scenarios, Scenario II exhibits an overall more idealized structure. Our results demonstrate the feasibility of the Dijkstra algorithm for precisely characterizing the polymer network structure. We expect this work will provide a new insight for the evaluation and description of gel networks and further help to reveal the dynamic process of network formation. [ABSTRACT FROM AUTHOR]

We use molecular dynamics simulations to unravel the physics underpinning the light-induced density changes caused by the dynamic trans–cis–trans isomerization cycles of azo-mesogens embedded in a liquid crystal polymer network, an intriguing experimental observation reported in the literature. We employ two approaches, cyclic and probabilistic switching of isomers, to simulate dynamic isomerization. The cyclic switching of isomers confirms that dynamic isomerization can lead to density changes at specific switch-time intervals. The probabilistic switching approach further deciphers the physics behind the non-monotonous relation between density reduction and light intensities observed in experiments. Light intensity variations in experiments are accounted for in simulations by varying the trans–cis and cis–trans isomerization probabilities. The simulations show that an optimal combination of these two probabilities results in a maximum density reduction, corroborating the experimental observations. At such an optimal combination of probabilities, the dynamic trans–cis–trans isomerization cycles occur at a specific frequency, causing significant distortion in the polymer network, resulting in a maximum density reduction. [ABSTRACT FROM AUTHOR]

Tracer diffusion in polymer networks and hydrogels is relevant in biology and technology, while it also constitutes an interesting model process for the dynamics of molecules in fluctuating, heterogeneous soft matter. Here, we systematically study the time-dependent dynamics and (non-Markovian) memory effects of tracers in polymer networks based on (Markovian) implicit-solvent Langevin simulations. In particular, we consider spherical tracer solutes at high dilution in regular, tetrafunctional bead-spring polymer networks and control the tracer–network Lennard-Jones (LJ) interactions and the polymer density. Based on the analysis of the memory (friction) kernels, we recover the expected long-time transport coefficients and demonstrate how the short-time tracer dynamics, polymer fluctuations, and the viscoelastic response are interlinked. Furthermore, we fit the characteristic memory modes of the tracers with damped harmonic oscillations and identify LJ contributions, bond vibrations, and slow network relaxations. Tuned by the LJ interaction parameter, these modes enter the kernel with an approximately linear to quadratic scaling, which we incorporate into a reduced functional form for convenient tracer memory interpolation and extrapolation. This eventually leads to highly efficient simulations utilizing the generalized Langevin equation, in which the polymer network acts as an additional thermal bath with a tunable intensity. [ABSTRACT FROM AUTHOR]

Scaffolded molecular networks are important building blocks in biological pigment–protein complexes, and DNA nanotechnology allows analogous systems to be designed and synthesized. System–environment interactions in these systems are responsible for important processes, such as the dissipation of heat and quantum information. This study investigates the role of nanoscale molecular parameters in tuning these vibronic system–environment dynamics. Here, genetic algorithm methods are used to obtain nanoscale parameters for a DNA-scaffolded chromophore network based on comparisons between its calculated and measured optical spectra. These parameters include the positions, orientations, and energy level characteristics within the network. This information is then used to compute the dynamics, including the vibronic population dynamics and system–environment heat currents, using the hierarchical equations of motion. The dissipation of quantum information is identified by the system's transient change in entropy, which is proportional to the heat currents according to the second law of thermodynamics. These results indicate that the dissipation of quantum information is highly dependent on the particular nanoscale characteristics of the molecular network, which is a necessary first step before gleaning the systematic optimization rules. Subsequently, the I-concurrence dynamics are calculated to understand the evolution of the vibronic system's quantum entanglement, which are found to be long-lived compared to these system–bath dissipation processes. [ABSTRACT FROM AUTHOR]

The network structure within polymers significantly influences their mechanical properties, including their strength, toughness, and fatigue resistance. All-atom molecular dynamics (AAMD) simulations offer a method to investigate the energy dissipation mechanism within polymers during deformation and fracture; Such an approach is, however, computationally inefficient when used to analyze polymers with complex network structures, such as the common chemically double-networked hydrogels. Alternatively, coarse-grained molecular dynamics (CGMD) models, which reduce the computational degrees of freedom by concentrating a set of adjacent atoms into a coarse-grained bead, can be employed. In CGMD simulations, a coarse-grained force field (CGFF) is a critical factor affecting the simulation accuracy. In this paper, we proposed a data-based method for predicting the CGFF parameters to improve the simulation efficiency of complex cross-linked network in polymers. Here, we utilized a typical chemically double-networked hydrogel as an example. An artificial neural network was selected, and it was trained with the tensile stress–strain data from the CGMD simulations using different CGFF parameters. The CGMD simulations using the predicted CGFF parameters show good agreement with the AAMD simulations and are almost fifty times faster. The data-inspired CGMD model presented here broadens the applicability of molecular dynamics simulations to cross-linked polymers and has the potential to provide insights that will aid the design of polymers with desirable mechanical properties. [ABSTRACT FROM AUTHOR]

Low-crosslinked polymer networks have recently been found to behave auxetically when subjected to small tensions, that is, their Poisson's ratio ν becomes negative. In addition, for specific state points, numerical simulations revealed that diamond-like networks reach the limit of mechanical stability, exhibiting values of ν = −1, a condition that we define as hyper-auxeticity. This behavior is interesting per se for its consequences in materials science but is also appealing for fundamental physics because the mechanical instability is accompanied by evidence of criticality. In this work, we deepen our understanding of this phenomenon by performing a large set of equilibrium and stress–strain simulations in combination with phenomenological elasticity theory. The two approaches are found to be in good agreement, confirming the above results. We also extend our investigations to disordered polymer networks and find that the hyper-auxetic behavior also holds in this case, still manifesting a similar critical-like behavior as in the diamond one. Finally, we highlight the role of the number density, which is found to be a relevant control parameter determining the elastic properties of the system. The validity of the results under disordered conditions paves the way for an experimental investigation of this phenomenon in real systems, such as hydrogels. [ABSTRACT FROM AUTHOR]

In recent years, ionic microgels have garnered much attention due to their unique properties, especially their stimulus-sensitive swelling behavior. The tunable response of these soft, permeable, compressible, charged colloidal particles is increasingly attractive for applications in medicine and biotechnologies, such as controlled drug delivery, tissue engineering, and biosensing. The ability to model and predict variation of the osmotic pressure of a single microgel with respect to changes in particle properties and environmental conditions proves vital to such applications. In this work, we apply both nonlinear Poisson–Boltzmann theory and molecular dynamics simulation to ionic microgels (macroions) in the cell model to compute density profiles of microions (counterions, coions), single-microgel osmotic pressure, and equilibrium swelling ratios of spherical microgels whose fixed charge is confined to the macroion surface. The basis of our approach is an exact theorem that relates the electrostatic component of the osmotic pressure to the microion density profiles. Close agreement between theory and simulation serves as a consistency check to validate our approach. We predict that surface-charged microgels progressively deswell with increasing microgel concentration, starting well below close packing, and with increasing salt concentration, in qualitative agreement with experiments. Comparison with previous results for microgels with fixed charge uniformly distributed over their volume demonstrates that surface-charged microgels deswell more rapidly than volume-charged microgels. We conclude that swelling behavior of ionic microgels in solution is sensitive to the distribution of fixed charge within the polymer-network gel and strongly depends on bulk concentrations of both microgels and salt ions. [ABSTRACT FROM AUTHOR]

Selective activation of the C–H bond of aromatic hydrocarbons is significant in synthetic chemistry. However, achieving oriented C–H activation remains challenging due to the poor selectivity of aromatic C–H bonds. Herein, we successfully constructed alternately arranged Au–C4 and Au–O4 organometallic coordination networks through selective aromatic C–H bond activation on Au(111) substrate. The stepwise reaction process of the 5, 12-dibromopyrene 3,4,9, 10-tetracarboxylic dianhydride precursor is monitored by high-resolution scanning tunneling microscopy. Our results show that the gold atoms in C–Au–C organometallic chains play a crucial role in promoting the selective ortho C–H bonds activation and forming Au–C4 coordination structure, which is further demonstrated by a comparative experiment of PTCDA precursor on Au(111). Furthermore, our experiment of 2Br-PTCDA precursor on Cu(111) substrate confirms that copper atoms in C–Cu–C organometallic chains can also assist the formation of Cu–C4 coordination structure. Our results reveal the vital effect of organometallic coordination on selective C–H bond activation of reactants, which holds promising implications for controllable on-surface synthesis. [ABSTRACT FROM AUTHOR]

The presence of gradient softer outer layers, commonly observed in biological systems (such as cartilage and ocular tissues), as well as synthetic crosslinked hydrogels, profoundly influences their interactions with opposing surfaces. Our prior research demonstrated that gradient-stiffness hydrogel layers, characterized by increasing elasticity with depth, control contact mechanics, particularly in proximity to the layer thickness. We postulate that the distribution of polymers within these gradient layers imparts extraordinary stretch and adhesion characteristics due to network adaptability and stress-induced reorganization. To investigate this phenomenon, we utilized Atomic Force Microscopy nanoindentation to assess the depth-dependent adhesion behavior of polyacrylamide hydrogels with varying gradient layer thicknesses. Two gradient layer thicknesses were achieved by employing different molding materials: glass and polyoxymethylene (POM). Glass-molded hydrogels exhibited a thinner gradient layer alongside a stiffer bulk layer compared to their POM-molded counterparts. In indentation experiments, the POM-molded hydrogel had larger adhesion compared to glass-molded hydrogel. We find that indenting within the gradient layer engenders increased load-unload hysteresis due to heightened fluid transport in the sparse outer polymer network. Consequently, this led to augmented adhesion and work of separation at shallow depths. We suggest that the prominent stretching capability of the sparse outer polymer network during probe retraction contributes to enhanced adhesion. The Maugis–Dugdale adhesive model only fits well to indentations on the thin layer or indentations which engage significantly with the bulk. These results facilitate a comprehensive characterization of adhesion mechanics in gradient-stiffness hydrogels, which could foster their application across emerging contexts in health science and environmental domains. [ABSTRACT FROM AUTHOR]

Micelles of anionic or zwitterionic surfactants produced depletion interactions between nanofibrils leading to weak gels, while cationic surfactants adsorbed to the nanofibrils, screening repulsions leading to tough gels or phase separation. Are fundamentally and technologically interesting due to their diverse building blocks, network-supporting attractive forces, and gelation pathways. As described below, the 29 articles that appear in this issue shed new light on a wide variety of related topics, including limited valence networks, bridged colloidal networks and coagulant gels, depletant-mediated gels, I in situ i structural characterization of gel aging, mechanical and rheological properties of colloidal networks, hybrid and deformable particle assemblies, and nanocrystal gels with tunable optical response. Bridged networks and coagulant gels Colloidal networks formed by nonspecific bridging polymers represent another interesting class of gel formers, although it can be challenging to design dispersible systems with tunable polymer-colloid interactions. [Extracted from the article]

In this investigation, a new micro‐crosslinked anionic polymer resistant to elevated temperature and high salinity, PKDASN, was synthesized using 3‐chloropropyltriethoxysilane (KMB703), N, N‐Dimethylacrylamide (DMAM), 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS), N‐vinyl caprolactam (NVCL), and sodium (4‐vinyl phenyl)methanesulfonate (SVM) employing free radical polymerization in a water‐based solution. The structure of PKDASN was analyzed using Fourier‐transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and X‐ray photoelectron spectroscopy, while its microstructure was analyzed using scanning electron microscopy. Thermogravimetric analysis showed that the pyrolysis temperature of PKDASN was above 294°C. Adding KMB703 enables the polymer to form a dense and stable spatial network. This intensified polymer network could interact with bentonite via intermolecular force and Coulomb force and form a dual grid structure, which presents impressive stability and control of filtration in saltwater. This is mainly achieved through creating a "silane coupling layer" on the particle surface by KMB703, which facilitates the crosslinking and aggregation of the polymer, thereby reinforcing the polymer's framework. This implies that under high‐temperature conditions of 230°C, 3 wt% PKDASN can improve the filtration effectiveness of drilling fluids and exhibit resistance to 15 wt% NaCl contamination. American Petroleum Institute filtration(FLAPI) and High temperature and high pressure filtration(FLHTHP) values were 4.6 and 23.0 mL, respectively. Therefore, this investigation provides a novel approach to utilizing the designated silane agent for the advancement of filtration loss additives in drilling fluids resistant to elevated temperature and high salinity. [ABSTRACT FROM AUTHOR]

The Chemical Communications journal, published by The Royal Society of Chemistry, features articles on various topics such as advances in oxygen catalysis, total synthesis of natural products, and the synthesis of different chemical compounds. The journal also covers research on batteries, energy storage, and the development of new materials for various applications. The articles in this issue highlight recent advancements in the field of chemistry and showcase innovative research in the chemical sciences. [Extracted from the article]

Hydrogels are insoluble three-dimensional polymer networks that are water insoluble but can absorb large amounts of water or biological fluid. They can be prepared using a variety of polymers, including both synthetic and natural ones. Either physical crosslinking, chemical crosslinking, or both are used for the preparation of polymeric hydrogels. Hydrogels made from natural polymers like chitosan, gelatin, alginate, cellulose, and hyaluronic acid are promising biomaterials for applications in tissue engineering, cosmetics, agriculture, wound healing, etc. because of their high biocompatibility and biodegradability. The present work reviews the classification of natural polymer-based hydrogels, properties, cross-linking methods, characterization, and their biomedical applications. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are promising alternatives to traditional antibiotics for treating skin wound infections. Nonetheless, their short half‐life in biological environments restricts clinical applicability. Covalent immobilization of AMPs onto suitable substrates offers a comprehensive solution, creating contact‐killing surfaces with long‐term functionality. Here, a copolymer of poly[(hydroxy ethyl acrylamide)‐co‐(4‐benzophenone acrylamide)‐co‐(pentafluorophenyl acrylate)‐co‐(ECOSURF EH‐3 acrylate)], in short poly(HEAAm‐co‐BPAAm‐co‐PFPA‐co‐EH3A), is synthesized by free radical polymerization. Subsequent modification of active ester groups with the amine groups of SAAP‐148, results in a copolymer, that is non‐cytotoxic to human lung fibroblasts. UV photocrosslinking of the benzophenone units yields a polymer network that forms a hydrogel after swelling with aqueous medium. Both the SAAP‐148‐modified polymer in solution and the photocrosslinked hydrogels show good antimicrobial activity against strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, including multidrug‐resistant strains, frequently found in wound infections. The covalent attachment of SAAP‐148 prevents leaching, ensuring sustained antimicrobial activity for at least 48 h in diluted human blood plasma and 14 days in PBS. This prolonged retention of antimicrobial activity in human blood plasma significantly enhances its clinical potential. Overall, this study shows the potential of the AMP‐functionalized photocrosslinkable polymer as antimicrobial wound dressings, providing an effective alternative to antibiotics. [ABSTRACT FROM AUTHOR]

Fiber‐based photochromic wearables have attracted growing attention in sustainable photo‐patterning information displays, information security encryption, and optical data recording/storage. Molybdenum trioxide (MoO3) is one of the key photochromic materials that possesses good photochromic performance, nevertheless, it faces considerable challenges in preparing photochromic textiles with stable, scalable, and long color‐retention properties. In this work, a new kind of fiber‐based photochromic wearables is designed and developed by combining cotton fabric with a MoO3‐based self‐adhesive polymer network and long chain silyl group. The prepared photochromic wearable has exhibited excellent fatigue resistance and favorable reversibility (> 40 cycles), rapid light response (reach color saturation with a UV dose of 60 kJ m−2), outstanding color retention capability (> 90 days), and desirable biocompatibility (cell viability > 100%). In addition, the prepared photochromic textiles could maintain a fast light response and excellent color retention even after experiencing repeated washing (20 cycles). Moreover, the photo‐patterning photochromic wearables are verified by resisting the deterioration of acid solution, alkali solution, and sweat (pH 2.0–9.0) as well as keeping clear patterns under sunlight irradiation. As a demonstration of the application, fiber‐based photochromic wearables are made and employed for the sustainable applications of rewritable photo‐patterning and information security encryption. [ABSTRACT FROM AUTHOR]

The "New Journal of Chemistry" published by the Royal Society of Chemistry features a variety of research articles in the field of chemistry. The latest issue includes papers on topics such as the synthesis of acyclic analogues of adenosine sulfonamides, construction of covalent organic frameworks, and studies on various chemical compounds and reactions. The journal aims to connect the global chemistry community and invest profits back into the field of chemistry. [Extracted from the article]

This study successfully prepared three environmentally friendly Schiff base network (SNW) polymers, SNW‐1, SNW‐2, and SNW‐3, using melamine and aldehyde compounds as raw materials through a microwave‐assisted synthesis method. The SNW materials were applied to catalyze the copolymerization reaction of SO2 and epoxides. Through detailed analysis of the chemical structure and properties of SNW‐1, SNW‐2, and SNW‐3, their catalytic efficiency was thoroughly investigated. Three thermal degradation kinetic models, Flynn–Wall–Ozawa (FWO), Kissinger, and Coats–Redfern, were employed to calculate the kinetic parameters of the thermal degradation of poly(cyclohexene sulfite) (PCS). Potential thermal degradation mechanisms were speculated. Additionally, the Kissinger model accurately described the thermal degradation kinetics features of PCS. Based on experimental results and kinetic analysis, this paper elucidates the potential mechanism of the copolymerization reaction of SO2 and epoxides. The study indicates that microwave‐assisted synthesis exhibits convenience and high efficiency in preparing efficient catalysts, demonstrating significant potential across various application domains. [ABSTRACT FROM AUTHOR]

In situ formed gel polymer electrolytes (GPEs) have advantages in safety and adaptability to current high‐voltage lithium‐ion batteries (LIBs). However, it is challenging for GPEs to achieve stable cycling at high current densities. A flexible framework is proposed for stable in situ GPE, by introducing ─CF3 groups to the polymer network to establish rapid Li+ transport channels, and incorporating secondary amine N─H groups to anchor anion. The obtained GPE exhibits a high ionic conductivity of 2.6 mS cm−1 and a high Li+ transference number of 0.67. The assembled Li||NCM811 cell demonstrates excellent rate performance, with a discharging capacity of 112.3 mAh g⁻¹ at 10C, and capacity retention of 87.6% after 260 cycles at 1C. Furthermore, the assembled graphite||NCM811 cell demonstrates excellent long‐term cycling stability with impressive capacity retention of 73.2% after 300 cycles 3C (1.8 mA cm−2). This work presents a promising approach to enhancing the cycling stability of GPEs for high‐voltage LIBs at high current density. [ABSTRACT FROM AUTHOR]

Membrane‐based gas separation offers notable energy efficiency benefits for hydrogen purification, yet it is often hindered by the inherent trade‐off between permeability and selectivity. To address this challenge, a novel mixed matrix membrane (MMM) design is presented to boost H2 separation performance via continuous hydrogen spillover mechanisms for the first time. The MMM incorporates a palladium‐functionalized ZIF‐67 gel (Pd@ZIF‐67 gel) network into a polymer of intrinsic microporosity (PIM‐1) matrix. The ZIF‐67 gel network serves as a uniform dispersion medium for palladium nanoparticles (Pd NPs), thereby generating a multitude of active sites. These exposed sites, in conjunction with the microporous structure of ZIF‐67, facilitate hydrogen dissociation and establish a continuous hydrogen spillover pathway throughout the membrane. This synergistic MMM design leads to substantial improvements in both hydrogen transport and selectivity. At an optimal loading of 28 wt% Pd@ZIF‐67 gel, the MMMs exhibit a H2 permeability of 3620 Barrer and a remarkable 417% enhancement in H2/CH4 selectivity (24.9), surpassing the 2008 upper bound. This approach paves the way for the development of advanced materials tailored for gas separation applications. [ABSTRACT FROM AUTHOR]

In this study, a pH- and temperature-responsive smart hydrogel was developed by utilizing Xanthan Gum (XG), N-Isopropylacrylamide (NIPAM), Vinyl Imidazole (VI), and Luffa cylindrical (LC). Semi-interpenetrating polymer networks (semi-IPNs) were created using free radical polymerization with N,N′-methylenebisacrylamide (MBA) as the cross-linker and ammonium persulfate (APS) as the initiator. Silver nanoparticles (AgNPs) were synthesized within semi-IPN hydrogel network structures to impart antibacterial properties. Malva sylvestris (MS) aqueous leaf extract was used as a reducing and stabilizing agent for the green synthesis of the AgNPs. The semi-IPN hydrogels exhibited pH- and temperature-responsive swelling behavior, which also enabled the controlled release of the drug. After 11 h, the cumulative release reached approximately 73% at pH 7.2 and 87% at pH 8.3. Additionally, the sustained release mechanism of the Trimethoprim drug was described using the Korsmeyer-Peppas model and was governed by Fickian diffusion. The drug-loaded semi-IPN@Ag nanocomposite hydrogel has demonstrated effective antibacterial activity against various Gram-negative and Gram-positive bacteria, indicating its promising potential as a wound dressing material for reducing infection risk. [ABSTRACT FROM AUTHOR]

Vanillyl alcohol has emerged as a widely used building block for the development of biobased monomers. More specifically, the cationic (photo‐)polymerization of the respective diglycidyl ether (DGEVA) is known to produce materials of outstanding thermomechanical performance. Generally, chain transfer agents (CTAs) are of interest in cationic resins not only because they lead to more homogeneous polymer networks but also because they strikingly improve the polymerization speed. Herein, the aim is to compare the cationic chain‐growth photopolymerization with the thermally initiated anionic step‐growth polymerization, with and without the addition of CTAs. Indeed, CTAs lead to faster polymerization reactions as well as the formation of more homogeneous networks, especially in the case of the thermal anionic step‐growth polymerization. Resulting from curing above the TG of the respective anionic step‐growth polymer, materials with outstanding tensile toughness (>5 MJ cm−3) are obtained that result in the manufacture of potential shape‐memory polymers. [ABSTRACT FROM AUTHOR]

This study successfully developed a bio-based, photocurable, anionic–nonionic dual-functional chain extender, and sulfonated cardanol-based polyethylene glycol (SCP), derived from renewable resources—cardanol and polyethylene glycol—for application in waterborne polyurethane dispersions (WPUDs). Utilizing SCP as a chain extender, WPUDs were prepared through a typical acetone process with poly(butylene adipate) (PBA), isophorone diisocyanate (IPDI), and ethylene diamine (EDA) at a constant NCO/OH ratio of 1:1. This research focused on the effects of polyethylene glycol molecular weight and SCP dosage on the particle size, stability, and film-forming properties of the WPUD. Optimal dispersion stability and film-forming performance were achieved with a polyethylene glycol molecular weight of 1500 and a PBA to SCP molar ratio of 4:1, yielding a particle size of 0.326 ± 0.010 μm and excellent storage stability over six months. The resulting WPU coatings exhibited a tensile strength of 11.4 MPa, which increased to 16.8 MPa after UV irradiation owing to the formation of a semi-interpenetrating network via the photopolymerization of cardanol's unsaturated side chains. UV cross-linking also enhanced water resistance, reducing the water absorption rate (WAR) from 18.68% to 4.21% and the water vapor transmission rate (WVTR) from 6.59 × 10−5 g·m⁻¹·Pa⁻¹·d⁻¹ to 2.26 × 10⁻⁵ g·m⁻¹·Pa⁻¹·d⁻¹, while also improving thermal stability. These findings demonstrate that SCP offers a sustainable and effective solution for developing high-performance WPU coatings. [ABSTRACT FROM AUTHOR]

In this work, firstly, the optimal performance ratio of potato starch and polyvinyl alcohol (PVA) was selected, and then the sustainable high-grade food packaging film was developed by adding different amounts (0, 5, 10, 15, 20, and 25 wt% based on the starch mass) of functional additive lignin into the starch - PVA film matrix. Starch - PVA based films with different amounts of lignin were studied from the aspects of morphology, physical and chemical properties, barrier properties, mechanical properties and antioxidant properties. Mechanical tests showed that lignin significantly improved the tensile strength (TS) of the film and effectively blocked the passage of water vapor. Lignin, starch and PVA were linked by hydrogen bond to form polymer network structure, which improved the interfacial compatibility between polymers. The interaction between polymer molecules and the distribution of lignin particles were confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The high content of phenolic hydroxyl in lignin undergoes proton coupled electron transfer mechanism, which endows the composite film with high antioxidant activity, which is proved by DPPH radical scavenging activity experiment. At the same time, it also gives the film excellent UV barrier and antibacterial properties. The introduction of lignin in this study provides a valuable way for the preparation of multifunctional composite films using biomass as raw materials, and has a potential application prospect in food packaging. [ABSTRACT FROM AUTHOR]

Material‐networked conduction paths provide nonlinear electronic properties, which are essential components of computing and physically mimic the brain. In this study, the formation of conjugated polymer monolayer networks and their nonlinear charge transport is demonstrated. Poly(3‐hexylthiophene) (P3HT) monolayer networks doped with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) is fabricated using the co‐spread method with an amphiphilic liquid crystal molecule at the air–water interface. Atomic force microscopy and Ultraviolet–visible–near‐infrared absorption spectroscopy measurements reveal the network surface morphologies and doped electronic states. The correlation between the nonlinear electronic characteristics and network structures of the P3HT/F4TCNQ monolayer networks is further systematically investigated through current–voltage and voltage–time measurements for various doping levels, network densities, and numbers of transferred layers. The current–voltage characteristics of the P3HT/F4TCNQ monolayer network device with a simple two‐terminal structure exhibit nonlinear and ohmic conduction behavior, which depend strongly on the network density and geometric dimension (number of transferred layers). It is concluded that the nonlinear properties arise from the limited and unique network of 2D conduction passes. This study highlights the unique features of conducting polymer monolayer networks, paving the way for neuromorphic device applications including conjugated semiconducting polymer‐based material reservoirs with controllable nanostructures. [ABSTRACT FROM AUTHOR]

In this study, a novel bio-based acrylic monomer derived from cardanol was synthesized and used in order to prepare acrylic copolymers that can be applied as thermoplastic polymers alone initially and then curable with the help of some driers to get a crosslink network similar to thermosetting polymers with their hydrophobic long alkyl chains having double bonds in their chemical structure. The synthesized polymers have the ability to be used in the paint or varnish formulations with or without paint driers. The synthesized monomers and polymers were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H NMR). Thermal properties of the polymers and obtained coatings therefrom were studied by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). The varnish's thermal and coating characteristics, such as its adhesion, gloss, hardness, salt spray resistance, and touch and hard drying times, were examined and analyzed. The results showed that the bio-based cardanol moieties improved the coatings' resistance to chemicals and saltwater exposure as well as their thermal and mechanical characteristics through the incorporation aromatic and long linear alkyl chains. The block copolymers with cardanol units were used both on its own to produce thermoplastic polymeric films and in conjunction with driers to get thermoset crosslinking networks. The contact angle of thermoset polymeric films with driers measured as 77° but in case of thermoplastic blank polymer, it was 61°. Furthermore, the Tg of blank polymer was 13.37 °C, but with the addition of 10% cardanol units and a small amount of driers, the Tg was increased to 53.12 °C. [ABSTRACT FROM AUTHOR]

A tetrafunctional glycidyl ether cyclic siloxane epoxy resin (TGTS) has been synthesized, characterized and cured with four aromatic amine hardeners: 1,3‐phenylenediamine (PDA), diethyltoluenediamine (DETDA), 4,4‐diaminodiphenylmethane (DDM) and 1,3‐bis(4‐aminophenoxy)benzene (APB). Each of the cured networks produces transparent and homogeneous networks, although when TGTS is cured with DETDA, reduced compatibility led to lower epoxide consumption, a more heterogenous microstructure and deleterious effects upon properties. Reduced miscibility of DETDA significantly impacts the chemical structure and microstructure of the network, resulting in significant reductions in thermal and mechanical properties but higher UV‐A transmission. The PDA‐, APB‐ and DDM‐cured networks conversely were more miscible and display properties typical of organic–inorganic hybrid networks, such as good mechanical properties at ambient and sub‐ambient temperatures, comparatively high glass transition temperatures, improved resistance to oxidation and lower UV‐A transmission. © 2024 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Efficient electrochemical CO2 reduction reaction (CO2RR) requires advanced gas‐diffusion electrodes (GDEs) with tunned microenvironment to overcome low CO2 availability in the vicinity of catalyst layer. Herein, for the first time, pyridine‐containing microgels‐augmented CO2 availability is presented in Cu2O‐based GDE for high‐rate CO2 reduction to ethylene, owing to the presence of CO2‐phil microgels with amine moieties. Microgels as three‐dimensional polymer networks act as CO2 micro‐reservoirs to engineer the GDE microenvironment and boost local CO2 availability. The superior ethylene production performance of the GDE modified by 4‐vinyl pyridine microgels, as compared with the GDE with diethylaminoethyl methacrylate microgels, indicates the bifunctional effect of pyridine‐based microgels to enhance CO2 availability, and electrocatalytic CO2 reduction. While the Faradaic efficiency (FE) of ethylene without microgels was capped at 43% at 300 mA cm−2, GDE with the pyridine microgels showed 56% FE of ethylene at 700 mA cm−2. A similar trend was observed in zero‐gap design, and GDEs showed 58% FE of ethylene at −4.0 cell voltage (>350 mA cm−2 current density), resulting in over 2‐fold improvement in ethylene production. This study showcases the use of CO2‐phil microgels for a higher rate of CO2RR‐to‐C2+, opening an avenue for several other microgels for more selective and efficient CO2 electrolysis. [ABSTRACT FROM AUTHOR]

Polymer dielectrics that perform efficiently under harsh electrification conditions are critical elements of advanced electronic and power systems. However, developing polymer dielectrics capable of reliably withstanding harsh temperatures and electric fields remains a fundamental challenge, requiring a delicate balance in dielectric constant (K), breakdown strength (Eb), and thermal parameters. Here, amide crosslinking networks into cyano polymers is introduced, forming asymmetric dipole pairs with differing dipole moments. This strategy weakens the original electrostatic interactions between dipoles, thereby reducing the dipole orientation barriers of cyano groups, achieving dipole activation while suppressing polarization losses. The resulting styrene‐acrylonitrile/crosslinking styrene‐maleic anhydride (SAN/CSMA) blends exhibit a K of 4.35 and an Eb of 670 MV m−1 simultaneously at 120 °C, and ultrahigh discharged energy densities (Ue) with 90% efficiency of 8.6 and 7.4 J cm−3 at 120 and 150 °C are achieved, respectively, more than ten times that of the original dielectric at the same conditions. The SAN/CSMA blends show excellent cyclic stability in harsh conditions. Combining the results with SAN/CSMA and ABS (acrylonitrile‐butadiene‐styrene copolymer)/CSMA blends, it is demonstrated that this novel strategy can meet the demands of high‐performing dielectric polymers at elevated temperatures. [ABSTRACT FROM AUTHOR]

Dielectric elastomer actuators (DEAs) face an acknowledged challenge: On the one hand, the majority of elastomers only achieve small electroactive deformation (<20%) in the absence of prestretch; on the other hand, rare elastomers capable of showing large electroactive deformation require relatively complicated processing and chemistry. This work addresses this challenge by fabricating an elastomer with a network of large side groups, which achieves a very large electroactive deformation (218%) without pre‐stretch. This elastomer can be rapidly and massively fabricated within a few min, by polymerizing a commercial monomer with a large alkyl side group. The large side groups in the polymer network repel each other and extend the load‐bearing strands, which results in a pronounced strain‐hardening behavior. This behavior helps the elastomer to get rid of electromechanical instability during actuation and hence to exhibit a large electro‐active deformation, a high energy density (>> human muscle), and a large output force (≈500 times self‐weight). the elastomer capable of manufacturing a soft electroactive gripper is demonstrated with large deformation, large force, and rapid response, which enables grasping fragile objects of various complex shapes in an agile away. [ABSTRACT FROM AUTHOR]

Integrating superior mechanical performance, anisotropic conductivity, and biocompatibility into conductive hydrogels as all‐in‐one human‐machine interaction device remains challenging. Herein, by mimicking the anisotropic structures of human muscles, a robust anisotropic conductive hydrogel is developed by initially aligning polyvinyl alcohol with polypyrrole decorated cellulose nanofibrils to form an anisotropically oriented polymer networks, followed by post‐crosslinking with tannic acid (TA). Introducing TA into hydrogel network permanently secures its hierarchically anisotropic structure through multiple hydrogen bonds, thus endowing the hydrogel with exceptional mechanical properties (tensile strength of 11.41 MPa, toughness of 12.44 MJ m−3), anisotropic adhesive property, and direction‐dependent conductivity. With these attributes, a hydrogel strain sensor with excellent multidirectional sensitivity is developed, enabling stable monitoring of multi‐degrees of freedom joint movements in the human body and facilitating the control of a multiaxial virtual robot manipulator. Moreover, the in vitro/vivo tests demonstrate exceptional biocompatibility and anti‐biofouling properties of the as‐prepared hydrogel sensor, maintaining stable electronic response signals for over 14 days after successful implantation into the Achilles tendon of mice. Overall, this study presents a promising approach for designing conductive hydrogels with superior mechanical properties and anisotropic functionality for emerging applications in both in vitro and in vivo human‐machine interface materials. [ABSTRACT FROM AUTHOR]

Inspired by the Mimosa plant, this study herein develops a unique dynamic shape memory polymer (SMP) network capable of transitioning from hard to pliable with heat, featuring reversible actuation, self‐healing, recyclability, and degradability. This material is adept at simulating the functionalities of artificial muscles for a variety of tasks, with a remarkable specific energy density of 1.8 J g−1—≈46 times higher than that of human skeletal muscle. As an intelligent manipulator, it demonstrates remarkable proficiency in identifying and handling items at high temperatures. Its suitable rate of shape recovery around human body temperature indicates its promising utility as an implant material for addressing acute obstructions. The dynamic covalent bonding within the network structure not only provides excellent resistance to solvents but also bestows remarkable abilities for self‐healing, reprocessing, and degradation. These attributes significantly boost its practicality and environmental sustainability. Anticipated to promote advancements in the sectors of biomedical devices, soft robotics, and smart actuators, this SMP network represents a forward leap in simulating artificial muscles, marking a stride toward the future of adaptive and sustainable technology. [ABSTRACT FROM AUTHOR]

Gelatin methacrylate (GM) and sodium alginate (SA) are two biomaterials that have been widely employed in tissue engineering, particularly in 3D bioprinting. However, they have some drawbacks including undesirable physico‐mechanical properties and printability, hindering their application. This work developed an interpenetrating polymeric network (IPN) of GM and SA reinforced with silica nanoparticles (SNPs) to deal with hydrogels’ drawbacks. Besides, for cross‐linking, visible light is used as an alternative to UV light to prevent disruptions in cellular metabolism and immune system reactions. Four GM/SA/SNP hydrogels different in SNPs concentration (0, 0.5, 1, and 2 w/w%) are studied. The performance of the hydrogels is evaluated in terms of physico‐mechanical properties (viscoelasticity, compressive modulus, degradation, and swelling), rheological properties, and biological properties (fibroblast cell growth and adhesion, and MTT assay). The results demonstrated that the GM/SA/SNP hydrogel with 1% SNPs provided desirable physical (645% swelling and 59.3% degradation), mechanical strength (270 kPa), rheological (tan δ of almost 0.14), and biological performances (≈98% viability after 3 days) while maintaining appropriate printability. The findings suggest that the GM/SA/SNP hydrogel holds great potential for applications in soft tissue regeneration. [ABSTRACT FROM AUTHOR]

Reaping the benefits of the burgeoning investigation of gels in recent decades, flexible electronics based on conductive gels have been extensively explored. Gels consisting of polymer networks and solvents provide ideal platforms for fabricating flexible electronics due to their soft mechanical nature, excellent biocompatibility, water‐like environment, and ease of processing. The majority of investigations of flexible electronics primarily focus on functionalities such as sensing capability, energy density, luminance, fluctuating frequency, and so on, whereas the distinguishing feature of flexible electronics lies in its inherent deformable mechanics in comparison to metal‐ or semiconductor‐based stiff electronics. However, the comprehensive design and investigation of the mechanical properties of deformable conductive gels have not received sufficient attention to improve the overall performance of flexible electronics. A comprehensive summary is provided, listing six crucial mechanical parameters—stretchability, modulus, strength, elasticity, hysteresis, and fatigue—which exert significant influence on the functionalities of flexible electronics. This review aims to direct researchers’ attention toward the mechanical design of deformable conductive gels and presents representative strategies for their mechanical modulation. [ABSTRACT FROM AUTHOR]

Multicellular organisms generate complex morphologies required for their function. Organisms control these morphologies by tuning active forces and by altering the emergent 'material properties' of a tissue, i.e. the rheology of the tissue. In many cases, organisms take advantage of dramatic changes in the rheology that occur when the material undergoes a rigidity transition from a fluid-like or floppy state to a solid-like or rigid state. This transition in turn depends on internal parameters at the scale of cells and molecules. This review highlights recent theoretical work identifying the mechanisms that drive such transitions, so that biologists can look for these mechanisms in in vivo or in vitro systems. We discuss two main types of transition: a first-order rigidity transition that depends on the connectivity of small-scale structures, such as the number of contacts between cells or the number of branch points in a biopolymer network; and a second-order rigidity transition that depends on the geometry of small-scale structures, such as the shape of cells or the distance between crosslinks in a polymer network. We provide examples of each type of transition in model organisms and discuss methods for distinguishing between the mechanisms in future experiments. In this review, Lisa Manning distills recent theoretical work identifying the mechanisms that drive rigidity transitions in mechanical networks, so that biologists can look for these mechanisms in specific in vivo or in vitro systems. [ABSTRACT FROM AUTHOR]

Colourful cholesteric liquid crystal polymer network (CLCN) films can selectively reflect circularly polarized light whose handedness is consistent with that of the CLCN films. The CLCN patterns have been applied for decoration and anti-counterfeiting. Herein, colourful patterns are prepared using a CLCN pattern and a nematic liquid crystal polymer network (NLCN) film. The structural colours are controlled by the helical pitches of the CLCN pattern. The NLCN film acts as the half-wave plate to invert the handedness of the circularly polarized lights reflected by the CLCN pattern. The sandwiched R-CLCN (right-handed CLCN)/NLCN/R-CLCN film can reflect both a left- and a right-handed circularly polarized light. The reflectance of this sandwiched film can be tuned by changing the NLCN and R-CLCN film thicknesses. Moreover, a colour pattern is also prepared based on this sandwiched structure, which is potentially applied for decoration and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Polymer gels stand out as emerging and promising materials in adhesives. However, flexible network and network–solvent mismatch affect their strengths and stabilities. Regulating the network architectures of polymer gels via molecular design is a promising strategy to overcome these drawbacks. Herein, a novel polymeric rigid cage (PRC) network structure design is proposed for capturing bulky vegetable oils via mechanically interlocking supramolecular interactions or steric hindrance effect to fabricate universal polymer gels‐based adhesives. By rationally designing and refining the architectures, the rigid cage prepared by 4,4′‐diphenylmethane diisocyanate (MDI) and N,N,N″,N″‐tetra(2‐hydroxypropyl) ethylenediamine (EDTP) possesses optimal encapsulation effect for epoxidized linseed oil (ELO). The resulting RCE‐50 gel exhibited robust mechanical properties (≈65 MPa) and excellent stability (high temperatures, high pressures, solvents immersion). Owing to high strength and stability of the polyurethane network, adhesion effect of high‐density amino ester groups, as well as the hydrophobic and toughening effects of ELO, the RCE‐50 gel can be used as a versatile adhesive with high adhesive strength under different conditions. This study proposes a new approach for innovating the properties of polymer gels, provides a novel idea for designing porous polymer materials, and offers fresh insights for developing versatile bio‐based adhesives. [ABSTRACT FROM AUTHOR]

Mussel‐inspired materials have been widely studied due to their excellent adhesion and self‐healing properties, but few studies have introduced this interesting property into the fracturing development of deep/ultra‐deep oil and gas fields. Herein, a new type of mussel‐inspired delayed crosslinking gel fracturing fluid is reported, which is formed by mussel‐inspired polymers containing many catechol groups and organic zirconium delayed crosslinkers. The strong supramolecular interaction in mussel‐inspired polymers can construct a more complex and stable dually cross‐linked polymer network based on conventional chemical crosslinking, to cope with harsh conditions such as high temperature and shear in reservoirs. After shearing at 200 °C, the reserved viscosity of mussel‐inspired delayed crosslinking gel is as high as 95 mPa·s. More importantly, the viscosity of gel remains basically unchanged at 25 °C, and the cross‐linking is completed within 300 s at 90 °C. The chemical force probe atomic force microscope (AFM) technology has successfully demonstrated that catechol groups are the main source of supramolecular interaction in mussel‐inspired polymers. The molecular simulation results show that due to the addition of catechol groups, the hydrogen bond interactions within the mussel‐inspired polymers molecules are enhanced. And the additional hydrogen bonds formed are more stable at high temperature. [ABSTRACT FROM AUTHOR]

Developing transparent and highly refractive environmentally friendly polymers has not been realized yet toward sustainable optoelectronics. This work describes poly(thiourea)s (PTUs) design following a new "polarizable group synergy" concept, combining highly polarizable hydrogen bonding groups and aromatic‐based spacers to form densely packed and high‐refractive‐index polymer networks. Specifically, PTUs containing m‐ and p‐phenylene spacers exhibit an easy synthesis, high thermostability (Tg = 159 °C), visible transparency (>92%T at 1 µm‐film), ultra‐high refractive index (nD = 1.81) based on the random H‐bonding arrays with a high packing constant (Kp = 0.738), and straightforward preparation of flexible films via solvent‐based techniques. Capitalizing on these assets, PTU‐films are integrated into benchmark graphene‐based lighting device architectures based on the light‐emitting electrochemical cells (LECs) concept. A joint optical modeling and experimental validation confirm the increase in external quantum efficiency expected by the enhanced light out‐coupling of PTU‐films. Finally, PTUs are efficiently depolymerized to low molecular weight compounds by simply adding diamines under heating, following the dynamic covalent bond exchange between thiourea moieties. Overall, this work highlights the PTU family as new promising materials with a unique polarizable H‐bond design to meet efficient and sustainable thin‐film lighting devices. [ABSTRACT FROM AUTHOR]

Thermoplastic elastomers (TPEs) based on styrenic block copolymers constitute excellent examples of self‐networking macromolecules that are employed in a wide range of contemporary technologies as molded parts. In such applications, these TPEs exist as dense (nonporous) films or other shapes. Here, it is first demonstrated that a series of commercial TPEs possessing comparable compositions can be electrospun from solution to form microfibers that are arranged into nonwoven mats that are breathable. An important consideration for microfiber formation is the copolymer molecular weight, which regulates i) the viscosity of the parent solution prior to electrospinning, ii) the ability of these copolymers to self‐assemble during electrospinning, iii) the microfiber morphology, and iv) the mechanical properties of the resultant microfibers. The addition of a midblock‐selective aliphatic oil to these TPEs yields thermoplastic elastomer gels (TPEGs), wherein the copolymer morphology and mechanical properties become highly composition‐tunable. Electrospinning TPEGs from a binary oil+solvent solution introduces a micelle inversion mechanism that begins with an oil‐rich micellar core and ends with a styrene‐rich micellar core, required for network stabilization, as the solvent dries during microfiber solidification. This work has implications for the production of controllably low‐modulus microfibrous materials possessing modestly improved toughness but exceptional extensibility and enhanced optical transparency. [ABSTRACT FROM AUTHOR]

Fabricating photonic crystals (PCs) with dynamic multi‐stimuli‐responsive structural colors, recordable colors, and self‐healable properties is significant for their emerging applications, yet remains a big challenge. Here, an all‐in‐one multifunctional PC (MFPC) film with outstanding mechanochromic, thermochromic, solvatochromic, color/shape‐recordable, self‐healable, and adhesive functions is designed and prepared by simply non‐close‐assembling silica particles into the unique 2‐[[(Butylamino)carbonyl]oxy]ethyl acrylate (BCOEA) followed by photopolymerization. The success is mainly due to the rational combination of non‐close‐packing structures and BCOEA's characteristics, including its urethane groups with numerous sacrificial hydrogen bonds, temperature‐dependent refractive index, swellable and deformable polymer network, as well as low glass‐transition temperature. The MFPC's hue and color saturation can be reversibly and dynamically modulated by strain/pressure/solvents and temperature, respectively, thereby realizing visually and spectrally sensing these stimuli. More interestingly, the color‐responsiveness combined with other functions endows MFPCs with fascinating emerging applications, including multilayer optical filters, inkless printing, reconfigurable multicolor patterns, stretching‐based anti‐counterfeiting, etc. This work offers a new perspective for designing next‐generation smart photonic materials and will facilitate their all‐round applications. [ABSTRACT FROM AUTHOR]

The complexation of microgels with rigid nanoparticles is an effective way to impart novel properties and functions to the resulting hybrid particles for applications such as in optics, catalysis, or for the stabilization of foams/emulsions. The nanoparticles affect the conformation of the polymer network, both in bulk aqueous environments and when the microgels are adsorbed at a fluid interface, in a non-trivial manner by modulating the microgel size, stiffness and apparent contact angle. Here, we provide a detailed investigation, using light scattering, in-situ atomic force microscopy and nano-indentation experiments, of the interaction between poly(N-isopropylacrylamide) microgels and hydrophobized silica nanoparticles after mixing in aqueous suspension to shed light on the network reorganization upon nanoparticle incorporation. The addition of nanoparticles decreases the microgels' bulk swelling and thermal response. When adsorbed at an oil-water interface, a higher ratio of nanoparticles influences the microgel's stiffness as well as their hydrophobic/hydrophilic character by increasing their effective contact angle, consequently modulating the monolayer response upon interfacial compression. Overall, these results provide fundamental understanding on the complex conformation of hybrid microgels in different environments and give inspiration to design new materials where the combination of a soft polymer network and nanoparticles might result in additional functionalities. [ABSTRACT FROM AUTHOR]

The geopolymerization reaction is a chemical process involving the dissolution of amorphous, semi-crystalline and crystalline phases following alkaline or acid attack at ambient or at low temperature (T˂100 °C). Together with precondensed entities of the used activator solution the dissolved parts form a geopolymer network which glues together all remaining unreacted parts as ingredients of the artificial stone. The fate of the mineralogical phases present in the precursors used in the synthesis of alkaline and acid geopolymers is reviewed in this article. The different starting materials used in the synthesis of geopolymers and the different techniques used to modify the reactivity of these materials are reported. The mineralogical evolution of the amorphous, semi-crystalline and crystalline phases after activation at ambient and at low temperatures (T < 100 °C) is also reported. This study shows that for the mineralogical investigation of raw material, precursors and geopolymers, XRD is the most widely used analytical method. The most commonly used method to confirm the participation of crystalline phases in geopolymerization is the comparison of the diffractograms of the raw material to those of the products. It also indicates that, in addition to the amorphous aluminosilicate phases, certain semi-crystalline, and crystalline phases participate in this geopolymerization dynamic either by undergoing total or partial dissolution to form an inorganic macromolecule with an amorphous structure of the zeolitic type and other new minerals. The composition of the phases formed depends on the base material. Increasing the synthesis temperature promotes the dissolution of phases, the formation of geopolymer networks, and in some cases, the formation of new phases such as sodalities, zeolite A and zeolite P. Little work has been done to quantify the mineralogical phases before and after precursor activation, making it impossible to assess dissolution, the degree of geopolymerization, and mineral formation. The exact structure of the phases formed is often questionable, as most of the papers do not mention their reference structure number. There is also a lack of quantification of the amorphous phase resulting from the hardening of the activating solution and the evaluation of the fraction of the amorphous phase contained in the precursor remains unreacted. The mineralogical investigation must also extend to the quantification of phases using Rietveld refinement with internal standards to correlate these with the physical and mechanical properties of geopolymer products. Additional mineralogical study techniques, such as thin sections, should be used in future work for in-depth mineralogical investigation of geopolymers. [ABSTRACT FROM AUTHOR]

Double polymer networks (DNs) consist of two interpenetrating polymer networks and can offer properties that are not merely a sum of the parts. Here, we report an elastic DN made from two supramolecular polymers (SMPs) that consist of the same poly(n‐butyl acrylate) (BA) backbone. The two polymers feature different non‐covalent binding motifs, which form dynamic, reversible cross‐links. The polymers were prepared by reversible addition−fragmentation chain‐transfer polymerization of n‐butyl acrylate and either the self‐complementary hydrogen‐bonding motif 2‐ureido‐4[1H]pyrimidinone, or the 2,6‐bis(1′‐methylbenzimidazolyl)pyridine ligand, which forms complexes with metal ions. The supramolecular DN made by these components combines features of the single networks, including high thermal stability and resistance to creep. The DN further exhibits excellent healability and displays a higher extensibility and a higher toughness than its constituents. The mechanical characteristics of the DN can be further enhanced by selectively pre‐stretching one of the networks, which is readily possible due to the reversible formation of the supramolecular cross‐links and their orthogonal stimuli‐responsiveness. [ABSTRACT FROM AUTHOR]

Ionogels, as a novel class of environmentally friendly electronic materials, have received extensive attention. This study successfully prepared P(AM‐co‐AA) ionogel with optical transparency and flexibility via chemical polymerization. Experimental outcomes reveal that the dispersion of anions and cations within the ionogel is effectively controlled by the polymer network, resulting in distinct dispersive dielectric property, which is suitable for applications in electromagnetic metamaterials. Leveraging these properties, two distinct electromagnetic metamaterial devices are developed: An Ionogel‐based Broadband Absorber achieves over 90% absorption across 10.9–25.36 GHz, and An Ionogel‐based Frequency Selective Rasorber (FSR) transmits within 4.62–5.86 GHz, exhibiting minimal insertion loss −1.45 dB and achieves greater than 90% absorption from 13 to 17.8 GHz. High agreement between experimental results and simulations validates the feasibility of utilizing ionogel in electromagnetic metamaterial applications and introduces a novel paradigm and methodology for designing and fabricating flexible electromagnetic metamaterial devices. [ABSTRACT FROM AUTHOR]

The document is the contents list for an issue of the journal Chemical Communications. It includes the titles and authors of various articles and communications related to chemistry research. Topics covered include the potential of MOF-based single-atom photocatalysts, anion-exchange membrane electrolyzers for hydrogen production, and progress on lithium-sulfur batteries. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

Environmentally‐friendly materials are increasingly sought in use of both structural and non‐structural applications. Most of the prominent places, particulates and fibers are exclusively utilized to reinforce polymeric composites, aiming to enhance their strength and provide effective protection against wear. Currently, one of the most pressing issues encountered in current industries are wear and tear, mostly happens during manufacturing and agricultural operations. To overcome this issue, the current study examines into exploring the effects of different weight ratios (0%, 1%, 3%, 5%, 7%, 9% by wt.%) of fly ash (FA) loading on the abrasive characteristics of Interpenetrating Polymer Networks (IPNs) composites strengthened with E‐Glass fibers. Abrasion tests, conducted in accordance with ASTM D99 standard which involves five control parameters: load, FA content, speed, sliding distance, and surface roughness. Experimental design utilized Taguchi's orthogonal array (L25), with opts ANOVA to identify significant control factors. Results indicate that the addition of FA substantially enhances the wear resistance of particulate‐loaded E‐Glass fiber reinforced IPN composites. Moreover, the specific wear rate is significantly influenced by the applied load and FA content. However experimental data suggests that optimal wear behavior for IPN composites occurs under the conditions of 50 N load, 3% FA content, 300 rpm speed, 4000 m sliding distance, and 0.3 μm disc roughness. Further, scanning electron microscopy was also employed to examine microstructural details to better know the micro‐mechanism behavior happens between the particulates with fiber and matrix reinforcement. Highlights: Utilization of fly ash significantly enhances composite strength.IPN laminates fabricated with 0%–7% particulate loads.IPN laminates thoroughly evaluated through wear testing.DOE guided experimental design using L25 orthogonal array.SEM analysis reveals superior quality of fly ash‐loaded IPN. [ABSTRACT FROM AUTHOR]

Soft matrices with tuned properties are part of the vast landscape of innovative materials for the restoration of works of art. "Twin chain" polymer networks (TC‐PNs) based on polyvinyl alcohol have proven unique as scaffolds for Cultural Heritage cleaning. They enable optimum adaptability, adhesion, porosity, and connectivity at both micro‐ and nano‐scale resulting in superior time/space‐controlled cleaning operations. In this work, TC‐PNs properties are tuned through a mild crosslinking of the poly(vinyl alcohol) (PVA)‐porogen polymer by using sebacic, adipic, or succinic acid. The modified porogens have different structural features imparting a different phase behavior to TC‐PVAs mixtures in aqueous solution, i.e., in pre‐gel systems used to form gels through a liquid–liquid phase separation. The macro‐, micro‐, and nanoscale features of the final gels are characterized by Confocal Laser Scanning Microscopy, Small Angle X‐ray Scattering, Rheology and are related to their cleaning performances. The study shows that the gels cleaning capacity is related to their tortuosity, that can be tailored at the nanoscale. Counterintuitively gels with higher tortuosity show better performances as evidenced by the cleaning of mockups and paintings from Jean Helion, Jackson Pollock, and Tancredi Parmeggiani at Peggy Guggenheim Collection in Venice. [ABSTRACT FROM AUTHOR]