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For the application of polymer gels, it is necessary to control independently and precisely their various physical properties. However, the heterogeneity of polymer gels hinders the precise control over the structure, as well as the verification of theories. To understand the structure-property relationship of polymer gels, many researchers have tried to develop a homogeneous model network. Most of the model networks were made from polymer melts that did not have a solvent and had many entanglements in the structure. Because the contribution of entanglements is much larger than that of chemical crosslinking, it was difficult to focus on the crosslinking structure, which is the structure considered in conventional theories. To overcome such a situation, we have developed a new model network system that contains much solvent. Specifically, we fabricated the polymer gel (Tetra-PEG gel) by mixing two types of solutions of tetra-armed poly(ethylene glycol) (Tetra-PEG) with mutually reactive end groups (amine (-PA) and activated ester (-HS)). Because the existence of a solvent strongly reduces the effect of entanglements, the effect of the crosslinking structure on the physical properties can be extracted. In this review, we present the structure-property relationship of Tetra-PEG gel. First, we show the structural homogeneity of Tetra-PEG gels. Then, we explain gelation reaction, elastic modulus, fracture energy and kinetics of swelling and shrinking of Tetra-PEG gels by comparing the theories and experimental results.

Gel dosimetry was developed in the 1990s in response to a growing need for methods to validate the radiation dose distribution delivered to cancer patients receiving high-precision radiotherapy. Three different classes of gel dosimeters were developed and extensively studied. The first class of gel dosimeters is the Fricke gel dosimeters, which consist of a hydrogel with dissolved ferrous ions that oxidize upon exposure to ionizing radiation. The oxidation results in a change in the nuclear magnetic resonance (NMR) relaxation, which makes it possible to read out Fricke gel dosimeters by use of quantitative magnetic resonance imaging (MRI). The radiation-induced oxidation in Fricke gel dosimeters can also be visualized by adding an indicator such as xylenol orange. The second class of gel dosimeters is the radiochromic gel dosimeters, which also exhibit a color change upon irradiation but do not use a metal ion. These radiochromic gel dosimeters do not demonstrate a significant radiation-induced change in NMR properties. The third class is the polymer gel dosimeters, which contain vinyl monomers that polymerize upon irradiation. Polymer gel dosimeters are predominantly read out by quantitative MRI or X-ray CT. The accuracy of the dosimeters depends on both the physico-chemical properties of the gel dosimeters and on the readout technique. Many different gel formulations have been proposed and discussed in the scientific literature in the last three decades, and scanning methods have been optimized to achieve an acceptable accuracy for clinical dosimetry. More recently, with the introduction of the MR-Linac, which combines an MRI-scanner and a clinical linear accelerator in one, it was shown possible to acquire dose maps during radiation, but new challenges arise.

Gel polymer electrolytes (GPEs) hold tremendous potential for advancing high-energy-density and safe rechargeable solid-state batteries, making them a transformative technology for advancing electric vehicles. GPEs offer high ionic conductivity and mechanical stability, enabling their use in quasi-solid-state batteries that combine solid-state interfaces with liquid-like behavior. Various GPEs based on different materials, including flame-retardant GPEs, dendrite-free polymer gel electrolytes, hybrid solid-state batteries, and 3D printable GPEs, have been developed. Significant efforts have also been directed toward improving the interface between GPEs and electrodes. The integration of gel-based electrolytes into solid-state electrochemical devices has the potential to revolutionize energy storage solutions by offering improved efficiency and reliability. These advancements find applications across diverse industries, particularly in electric vehicles and renewable energy. This review comprehensively discusses the potential of GPEs as solid-state electrolytes for diverse battery systems, such as lithium-ion batteries (LiBs), lithium metal batteries (LMBs), lithium–oxygen batteries, lithium–sulfur batteries, zinc-based batteries, sodium–ion batteries, and dual-ion batteries. This review highlights the materials being explored for GPE development, including polymers, inorganic compounds, and ionic liquids. Furthermore, it underscores the transformative impact of GPEs on solid-state batteries and their role in enhancing the performance and safety of energy storage devices.

In this work, effect of varying lithium perchlorate (LiClO 4 ) salt concentration in polymer gel electrolytes (PGE) containing heat resistant polymethyl methacrylate (PMMA), and succinonitrile (SN) is investigated via electrochemical and physical properties. The electrolyte specimen with high LiClO 4 salt concentration of 1.5 M supports maximum ionic conductivity of 4.9 × 10 –5 S cm −1 and electrochemical stability window of ~ 4 V. The ion-transport parameters evaluated from the tangent loss studies confirms that the optimized electrolyte possesses diffusivity (D) of 4.52 × 10 –2 , mobility (μ) of 1.746 cm 2  V −1  s −1 , number of charge carriers (N) of 1.78 × 10 14  cm −3 and Nµ of 3.106 × 10 14  cm −1  V −1  s −1 . The dielectric constant studies show that the optimized electrolyte possesses maximum dielectric constant and lower value of modulus towards the high frequency region. The thermogravimetric and differential scanning calorimetry studies confirms that the prepared electrolytes offer weight loss of < 9% up to 373 K and maintains the gel phase up to 570 K, respectively. X-ray diffraction suggest that the PGE system becomes more amorphous with progressive addition of LiClO 4 up to 1.5 M, while the Fourier transform Infra-red (FTIR) spectroscopy study reveal the salt-polymer interactions. Graphical Abstract

Polymer gel is a promising system for conformance control and water shutoff in water flooding reservoirs. However, the presence of fractures in reservoirs poses a major challenge to the successful application of polymer gels. This is because direct visualization of polymer gel system flow in the fracture is still lacking. In this paper, the HPAM/CrAc gel system was used to study the transport and plugging characteristics of gel multi-slug plugging using a visualized fracture model. The experimental results showed that multi-slug plugging accompanied by gradual compaction significantly improved the blocking strength of the polymer gel within the fracture. Specifically, multi-slug plugging improves the pressure gradient of the chasing water by approximately 80-200 kPa/m compared to one-step plugging of the polymer gel. During multi-slug plugging of the fracture, the later injected gelant slugs pass through the weak areas of the prior matured gel slugs and continue to move behind them instead of pushing the prior matured gel as a whole to the distal portion of the fracture. After the polymer gel one-step plugging of the fracture, chasing water will pass through the edges of the fracture where the gel is not adequately filled or directly through the mature gel in the form of wormholes. In contrast, after multi-slug plugging of the fracture, the mature gel is not easy to be breached by chasing water because of the compaction effect, while the junction between the mature gels of each slug will become an easy area for chasing water to break through. But it is still more difficult to break through than the one-step plugging process. This research is informative for the improvement of polymer gel systems and their successful application in fractured reservoirs for conformance control and water shutoff.

The development of science and technology of advanced materials using nanoscale units can be conducted by a novel concept involving combination of nanotechnology methodology with various research disciplines, especially supramolecular chemistry. The novel concept is called 'nanoarchitectonics' where self-assembly processes are crucial in many cases involving a wide range of component materials. This review of self-assembly processes re-examines recent progress in materials nanoarchitectonics. It is composed of three main sections: (1) the first short section describes typical examples of self-assembly research to outline the matters discussed in this review; (2) the second section summarizes self-assemblies at interfaces from general viewpoints; and (3) the final section is focused on self-assembly processes at interfaces. The examples presented demonstrate the strikingly wide range of possibilities and future potential of self-assembly processes and their important contribution to materials nanoarchitectonics. The research examples described in this review cover variously structured objects including molecular machines, molecular receptors, molecular pliers, molecular rotors, nanoparticles, nanosheets, nanotubes, nanowires, nanoflakes, nanocubes, nanodisks, nanoring, block copolymers, hyperbranched polymers, supramolecular polymers, supramolecular gels, liquid crystals, Langmuir monolayers, Langmuir-Blodgett films, self-assembled monolayers, thin films, layer-by-layer structures, breath figure motif structures, two-dimensional molecular patterns, fullerene crystals, metal-organic frameworks, coordination polymers, coordination capsules, porous carbon spheres, mesoporous materials, polynuclear catalysts, DNA origamis, transmembrane channels, peptide conjugates, and vesicles, as well as functional materials for sensing, surface-enhanced Raman spectroscopy, photovoltaics, charge transport, excitation energy transfer, light-harvesting, photocatalysts, field effect transistors, logic gates, organic semiconductors, thin-film-based devices, drug delivery, cell culture, supramolecular differentiation, molecular recognition, molecular tuning, and hand-operating (hand-operated) nanotechnology.

Remarkable improvement in the polarization and charge transport at the solid–solid electrode–electrolyte interface due to the incorporation of a redox‐active additive sodium molybdate (Na2MoO4) is demonstrated. The presence of the electrochemically active oxide center along with Na+ facilitates the hopping‐based charge transport of the ionic liquid leading to higher ionic conductivity and a twofold increase in specific capacitance (0.009 to 0.018 F cm−2). This drives a 200% increase in the energy density (0.76–1.7 µW h cm−2) and a 2.5 times improvement in the rate capability (10 000 mV s−1) of the solid‐state supercapacitor. Importantly, the power density, non‐Faradic nature, and cyclability remain unaltered, resulting in performance exceeding several solid‐state and liquid electrolyte‐based supercapacitors. Thus, the results established here through the use of redox‐active additive establish the robustness of the approach and practicality of the resulting device besides providing transformative opportunities in tuning the performance of solid‐state devices. A symmetric supercapacitor assembled with a polymer‐gel‐electrolyte, composed of methyl‐cellulose, 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide, sodium molybdate delivers over 200% increase in the energy density without affecting the power density and long‐term cyclability.

Polymer gels with suitable viscoelasticity and deformability have been widely used for formation plugging and lost circulation control, profile control, and water shutoff. This article systematically reviews the research progress on the preparation principle, temperature resistance, salt resistance, and mechanical properties of the ground and in situ crosslinked polymer gels for oil-gas drilling and production engineering. Then, it comparatively analyzes the applicable conditions of the two types of polymer gel. To expand the application range of polymer gels in response to the harsh formation environments (e.g., high temperature and high salinity), we reviewed strategies for increasing the high temperature resistance, high salt resistance, and rheological/mechanical strengths of polymer gels. This article provides theoretical and technical references for developing and optimizing polymer gels suitable for oil-gas drilling and production.

Thermoresponsive polymer gels are a type of intelligent material that can react to changes in temperature. These materials possess excellent innovative properties and find use in various fields. This paper systematically analyzes the methods for testing and regulating phase transition temperatures of thermo-responsive polymer gels based on their response mechanism. The report thoroughly introduces the latest research on thermo-responsive polymer gels in oil and gas extraction, discussing their advantages and challenges across various environments. Additionally, it elucidates how the application limitations of high-temperature and high-salt conditions can be resolved through process optimization and material innovation, ultimately broadening the scope of application of thermo-responsive polymer gels in oil and gas extraction. The article discusses the technological development and potential applications of thermo-responsive polymer gels in oil-based drilling fluids. This analysis aims to offer researchers in the oil and gas industry detailed insights into future possibilities for thermo-responsive polymer gels and to provide helpful guidance for their practical use in oil-based drilling fluids.

Addressing the complex issue of lost circulation in drilling operations is crucial as it increases nonproductive time and costs. Conventional gel plugging materials often exhibit low temperature resistance, poor pumpability, and low pressure-bearing capacity. To overcome the limitations, a self-made polymer (HSA) was initially synthesized and mixed with two crosslinker agents (MBA/PEI) at room temperature to induce a new type of high-temperature-resistant and pressure-resistant polymer gel agent (HSA-G). Investigating the gel strength and plugging capacity, the vertical inverted tube observation, 71-type high-temperature and high-pressure (HTHP) instruments, and high-pressure filter with varying fracture cracks (3–5 mm) were employed. HSA-G demonstrated excellent gelation strength for 4–5 h at 140 °C, while retaining more than 57% of its gel strength after aging at 140 °C for 144 h, which is 3 times higher than the commercially available hydrolyzed polyacrylamide (HPAM + PEI). The excellent performance was attributed to the synergy between PEI-MBA, which induces tight-crosslinked interconnected structure within HSA-G, mitigating fluid losses to only 72 mL compared to 194 mL for HPAM-G, under 8.5 MPa in the HTHP sand bed at 140 °C. In the fracture leakage simulations using a 5 mm crack performed at 6 MPa at room temperature, the filtration loss of HSA-G is 300 mL, almost half that of HPAM-G, showcasing its superior plugging and high-pressure bearing performance. In conclusion, HSA-G has not only demonstrated operational effectiveness in reducing downtime costs and fluid losses but can also temporally replace cement plugging to prevent reservoir contamination in alignment with environmentally friendly practices.