Intercalation Structure Research Articles

Microstructure development and dynamic-mechanical properties of polybutadiene rubber/nanoclay: Effect of curing system

This study investigates the fabrication and characterization of polybutadiene rubber (BR) nanocomposites incorporating organoclay (OC) through melt mixing with a focus on the microstructure development and properties of the cured materials using sulfur curing and electron beam irradiation. The role of epoxidized natural rubber (ENR50) as a compatibilizer to improve interfacial interactions is explored. X-ray diffractometer (XRD) and scanning electron microscopy (SEM) analyses confirm the intercalation structure of clay nanoplates within the nanocomposites. Mechanical properties measurements highlight the enhancement of tensile strength and elongation at break with increasing nanoclay content in sulfur-cured nanocomposites while in the case of the irradiated samples the tensile strength increased as the nanoclay content increased from 3 to 7 wt% up to a dose of 150 kGy after which it decreased with further dose increments and exhibit a dose-dependent behavior. Dynamic Mechanical Analysis (DMA) reveals a strong chain-nanoparticle interaction with irradiated samples at 150 kGy displaying superior storage modulus and reduced loss factor compared to sulfur-cured counterparts. Furthermore, the incorporation of ENR50 as a compatibilizer proved beneficial in enhancing the interaction between the BR chains and the modified nanoclay. These findings offer valuable insights into the design and performance of rubber nanocomposites for advanced applications.

The evolution of chemical ordering and property in Fe1+x Se2 upon intercalation ratios.

Intercalation has been considered as an effective method to explore innovative two-dimensional (2D) materials and modify their properties. However, the relationship between intercalation concentration, structure, and property remains a largely uncharted territory, and the controllable synthesis of desired intercalated phases faces challenges. Here, a general intercalated rule for the effect of self-intercalation ratio on atomic arrangements is revealed. Then, the controllable synthesis of a series of Fe-intercalated 2D materials is realized. Scanning transmission electron microscopy illustrates that their intercalation structures undergo disordered/ordered/half-ordered/ordered transformation, which confirms the intercalated rule and proposes a new structure termed half-ordered intercalation. Notably, their magnetic and electrical properties can be significantly modulated by intercalation. Orderly intercalated nanoflakes possess room-temperature magnetism with composition-regulated magnetic domains. Moreover, Fe1.5Se2 and Fe1.6Se2 are scarce half-metallic materials showing different magneto-resistance behaviors. This work would guide the design and synthesis of new intercalated materials, and deepen the understanding of the relationship between structure and properties.

The electric regulation mechanism of drug molecules intercalating with DNA

The insertion of small drug molecules into DNA can change its electrical properties, thereby controlling the probability of its electrical transmission. This characteristic has enabled its widespread application in molecular electronics. However, the current understanding of the intercalation properties and electronic transmission mechanisms is still not deep enough, which severely restricts its practical application. In this paper, the density functional theory and the non-equilibrium Green's function formula are combined to bind three different small drug molecules to the same sequence of DNA through intercalation, in order to discuss the impact of intercalation and molecular structure on the electrical properties of DNA. After inserting two MAR70 molecules, the conductivity decreased from 2.38 × 10−5 G0 to 3.37 × 10−7 G0. Upon the insertion of Nogalamycin, the conductivity dropped to 2.01 × 10−5 G0, only slightly lower than that of bare B-DNA. However, when cyanomorpholinodoxorubicin was inserted, the conductivity was 2.65 × 10−6 G0. In our study, we observed some common characteristics. After intercalating with drug molecules, new energy levels were induced, altering the positions of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels, resulting in a narrowed bandgap and consequently reduced conductivity of the complex. Furthermore, the conductivity was also related to the number of inserted drug molecules, fewer inserted molecules led to a decrease in conductivity. The results of this study indicate that embedding drug molecules can reduce or regulate the conductivity of DNA, providing new insights for its application in the field of nanoelectronics.

Multifunctional Water Additive Enabling Stable Cycling of Chloride-Free Magnesium Metal Batteries Based on Carbonate Electrolyte.

Rechargeable magnesium batteries (RMBs) face with the challenge of interphase passivation between electrolytes and Mg anodes. Compared with ether electrolytes, carbonate solvents possess the superior electrochemical stability at cathode side, but their incompatibility with Mg metal, high viscosity, and desolvation energy barrier restrict their practical utilization in RMBs. Herein, the "unwanted-impurity" water with high concentration is revisited and employed as multifunctional additive in carbonate electrolyte to improve the reversibility of RMBs. Water additive enables the localized deep eutectic effect, reduces the viscosity of carbonate electrolyte, and improves the Mg ion conductivity. The water molecules also participate the solvation sheath of Mg ions, resulting in the reduction of Mg deposition overpotential and inhibition of parasitic reaction. Furthermore, the co-intercalated water molecules in V2O5 cathode layers enable the stabilization of intercalation structure and supply of additional magnesiophilic sites. Cooperated with the binder-decorated Mg powder anode, the propylene carbonate electrolyte with water additive endows Mg||Mg symmetric cells and Mg||V2O5 full cells with satisfactory cycling performance and high-voltage stability. This work revisits the impact of impurity water and provides a practical strategy for the utilization of conventional low-cost carbonate electrolyte family, broadening the design and formulation of electrolytes for chlorine-free and high-voltage RMBs.

Polyvinylidene fluoride-based loose nanofiltration membrane with graphene oxide intercalation for efficient small organic molecules desalination

Graphene oxide (GO) loose nanofiltration (LNF) membranes show immense potential for the desalination of small organic molecules. However, it remains a significant challenge to compare the performance of GO LNF membranes prepared via different doping methods and study the mechanisms that influence the separation abilities of the membranes. In this study, LNF membranes prepared via three GO doping methods were examined for flux, retention rate, and the separation performance of small organic molecules and inorganic salts. The membranes coated with dopamine (DA) and GO, and subsequently formed polydopamine (PDA)–GO intercalation, showed the best results. A novel LNF membrane material (PVDF/PDA–GO–TFN; PVDF: polyvinylidene fluoride, TFN: thin-film nanocomposite) was developed to enhance the separation performance of small organic molecules and inorganic salts while improving membrane surface stabilization and anti-fouling performance and reducing the “trade-off” effect. The optimal conditions for PDA–GO intercalation and the best combination for interfacial polymerization (IP) were also determined. The intercalation structure was identified via scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier-transform infrared spectroscopy. Furthermore, the separation mechanism of the membrane was determined to be based on the Donnan and steric hindrance effects, according to the correlation analysis of the membrane surface electrical properties (zeta potential), hydrophilicity (contact angle), and pore properties. The PVDF/PDA–GO–TFN LNF membrane displayed a maximum water permeance of 10.45 L/(m2·h·bar), with an 88 % rejection of PEG2000 and a 6.83 % rejection of Na2SO4. Moreover, the membrane exhibited excellent anti-fouling performance and long-term stability, with a mean flux recovery rate of 99.06 % after four cycles of filtration and backwashing tests using small organic molecules and inorganic salt solutions. The inorganic salt retention rate was analyzed using SPSS software, and the results indicated excellent membrane stability. In summary, the preparation of PVDF/PDA–GO–TFN membrane materials provides a novel approach for fabricating LNF membranes that can effectively separate small organic molecules and inorganic salts.

Electrochromic properties of sputter-grown Nb18W16O93 thin films

Large-area electrochromic films with high stability under high temperatures and humid conditions are essential for the commercialization of smart windows. In this paper, we introduce a new cathodic coloration Nb18W16O93 thin film produced using sputtering that exhibits excellent electrochromic modulation, superior chemical stability, and cyclic durability owing to its stable host structure for ion intercalation. The electrochemical properties of the as-grown Nb18W16O93 thin films, including charge density and transmittance modulation, were enhanced with increasing deposition temperatures. The annealed Nb18W16O93 thin films (grown at room temperature) exhibited comparable electrochromic performances to films grown at high temperatures. Electrochromic devices composed of annealed and high-temperature-grown Nb18W16O93 thin films exhibited excellent durability and nearly identical transmittance modulation, even after 10,000 test cycles. Furthermore, degradation of the surface morphology of the Nb18W16O93 thin films after etching in heated water was alleviated, suggesting high stability under hot and humid conditions, whereas the flat surface of the room-temperature-grown WO3 thin films degraded significantly.

Polyphenol mediated α-FeOOH/g-C3N4 heterojunction membrane for fast purification of surfactant-stabilized O/W emulsions with super-wetting and Photo-Fenton self-cleaning functions

In the practical purification of oily wastewater, the application of polymer-based membrane is greatly restricted due to the oil adhesion and complicated fouling problems. Herein, to conquer the aforementioned challenges, we prepared the polyphenol mediated Photo-Fenton self-cleaning and superhydrophilic/underwater superoleophobic α-FeOOH/g-C3N4@PVDF composite membrane via simple vacuum-assisted self-assembly technology. The g-C3N4 nanosheets modified by tannic acid were introduced into the surface of PVDF ultrafiltration membrane, in which the intercalation structure was regulated by the random interpenetration of α-FeOOH nanorods. The abundant hydroxyl and amino groups and the rough micro-nano structure formed by intercalation structure were favorable for the superhydrophilic feature (WCA = 0°, UOCA>150°), thus resulting in ultra-low oil adhesion. Specially, the intercalation structure improved the water permeation channel, further promoting the water/oil separation flux. Therefore, the composite membrane exhibited superior separation flux (452.35–650.21 L m−2 h−1) and separation efficiency (>99.06 %) for various surfactant-stabilized emulsions. Moreover, thanks to the Photo-Fenton reaction, the composite membrane showed excellent degradation efficiency on simulated pollutants (various dyes) within 60 min (MeB: 95.55 %, CR: 90.83 %, MO: 98.90 %, CV: 95.11 %), showing satisfactory photocatalytic self-cleaning performance. This work provides a strategy for the potential application of polymer-based membranes in the treatment of complex surfactant-stabilized emulsion wastewater from petrochemical industry.

High performance multifunctional piezoelectric PAN/UiO-66-NO2/MXene composite nanofibers for flexible touch sensor

In this study, a flexible piezoelectric sensor based on polyacrylonitrile (PAN), zirconium-based MOF (UiO-66) with nitro (NO2) and two-dimensional material MXene composite nanofiber film was proposed. When pressure was applied, the three-dimensional structural nanopores were compressed, increasing the intercalation structure between the MXene nanosheets coated in the fibers. The double-packed system produced a higher resistance change under the same pressure load, which can be explained by the fact that the low-conductivity octahedral UiO-66-NO2 particles acted as a similar “buffer” between the highly conductive MXene. At the same time, a large number of hydrogen bonds between the surfaces of the two fillers enhanced the synergistic effect and promoted the interfacial coupling effect, so that more 31-helical conformation in the PAN matrix was converted into a planar zigzag conformation. This improved the piezoelectric performance and enabled the sensor to have a voltage output of about 200 V in the detection range. And because the polyhedral form of UiO-66-NO2 particles provided a rougher surface structure, the piezoelectric sensor can achieve a high sensitivity of 5.62 V/N. The other results showed that the dielectric constant of the designed flexible piezoelectric sensor was increased to 2.67, the dielectric loss was kept at a low level of 0.026, and the maximum elongation was 56.03 %. This multi-functional sensor shows great potential in the fields of health and medical treatment, human-computer interaction, etc.

Deciphering Anion-Modulated Solvation Structure for Calcium Intercalation into Graphite for Ca-Ion Batteries.

Co-intercalation reactions make graphite a feasible anode in Ca ion batteries, yet the correlation between Ca ion intercalation behaviors and electrolyte structure remains unclear. This study, for the first time, elucidates the pivotal role of anions in modulating the Ca ion solvation structures and their subsequent intercalation into graphite. Specifically, the electrostatic interactions between Ca ion and anions govern the configurations of solvated-Ca-ion in dimethylacetamide-based electrolytes and graphite intercalation compounds. Among the anions considered (BH4 -, ClO4 -, TFSI- and [B(hfip)4]-), the coordination of four solvent molecules per Ca ion (CN=4) leads to the highest reversible capacities and the fastest reaction kinetics in graphite. Our study illuminates the origins of the distinct Ca ion intercalation behaviors across various anion-modulated electrolytes, employing a blend of experimental and theoretical approaches. Importantly, the practical viability of graphite anodes in Ca-ion full cells is confirmed, showing significant promise for advanced energy storage systems.

Deciphering Anion‐Modulated Solvation Structure for Calcium Intercalation into Graphite for Ca‐Ion Batteries

AbstractCo‐intercalation reactions make graphite a feasible anode in Ca ion batteries, yet the correlation between Ca ion intercalation behaviors and electrolyte structure remains unclear. This study, for the first time, elucidates the pivotal role of anions in modulating the Ca ion solvation structures and their subsequent intercalation into graphite. Specifically, the electrostatic interactions between Ca ion and anions govern the configurations of solvated‐Ca‐ion in dimethylacetamide‐based electrolytes and graphite intercalation compounds. Among the anions considered (BH4−, ClO4−, TFSI− and [B(hfip)4]−), the coordination of four solvent molecules per Ca ion (CN=4) leads to the highest reversible capacities and the fastest reaction kinetics in graphite. Our study illuminates the origins of the distinct Ca ion intercalation behaviors across various anion‐modulated electrolytes, employing a blend of experimental and theoretical approaches. Importantly, the practical viability of graphite anodes in Ca‐ion full cells is confirmed, showing significant promise for advanced energy storage systems.

Constructing a 3D Ion Transport Channel-Based CNF Composite Film with an Intercalated Structure for Superior Performance Flexible Supercapacitors.

The weak stiffness, huge thickness, and low specific capacitance of commonly utilized flexible supercapacitors hinder their great electrochemical performance. Learning from a biomimetic interface strategy, we design flexible film electrodes based on functional intercalated structures with excellent electrochemical properties and mechanical flexibility. A composite film with high strength and flexibility is created using graphene (reduced graphene oxide (rGO)) as the plane layer, layered double metal hydroxide (LDH) as the support layer, and cellulose nanofiber (CNF) as the connection agent and flexible agent. The interlayer height can be adjusted by the ion concentration. The highly interconnected network enables excellent electron and ion transport channels, facilitating rapid ion diffusion and redox reactions. Moreover, the high flexibility and mechanical properties of the film achieve multiple folding and bending. The CNF-rGO-NiCoLDH film electrode exhibits high capacitance performance (3620.5 mF cm-2 at 2 mA cm-2), excellent mechanical properties, and high flexibility. Notably, flexible all-solid assembled CNF-rGO-NiCoLDH//rGO has an extremely high area energy density of 53.5 mWh cm-2 at a power density of 1071.2 mW cm-2, along with cycling stability of 89.8% retention after 10 000 charge-discharge cycles. This work provides a perspective for designing high-performance energy storage materials for flexible electronics and wearable devices.

Compatibility, Microstructure, and Mechanical Properties of a Dimethyl-Sulfoxide-Pretreated Graphene-Modified Asphalt Binder.

The surface of graphene was pretreated with dimethyl sulfoxide to enhance its dispersion in asphalt. To investigate the compatibility, microstructure, and mechanical properties of a dimethyl-sulfoxide-pretreated graphene (DG)-modified asphalt (DG asphalt). The interaction between asphalt and DG, DG dispersion, functional groups, tensile performance, microscopic structures, and micromechanical properties of the DG asphalt were characterized. Results indicate that DG with a particle size range from 0 to 8 μm is uniformly dispersed in asphalt. The irregular distribution of DG enhances the stress transfer distance, thus improving the energy consumption and mechanical properties of the DG asphalt. The preparation process involves physical blending, which reduces the saturated hydrocarbon content and increases the chemical bond energy, ultimately enhancing mechanical properties. Additionally, the surface of the DG asphalt shows numerous smaller sized bee structures, which contribute to the hardening and smoothness of the asphalt surface. The stress is distributed uniformly across the surface of the DG asphalt, minimizing stress concentrations. Furthermore, the light components in asphalt are adsorbed by DG, forming intercalated structures that decrease the adhesion and energy dissipation when compared to base asphalt. The compressive stress within bee structures consumes more energy and enhances the anti-deformation capacity of the DG asphalt. However, at higher deformation levels, the slipping of intercalated DG decreases its anti-deformation capacity when compared to that of base asphalt. Nonetheless, the interaction between intercalated structures prevents rapid tensile failure in the DG asphalt.

Research progress on the flame retardation and modification of polypropylene by montmorillonite

Montmorillonite can be used to achieve nano-dispersion level by forming peel or intercalation structure in polypropylene body, so as to improve the mechanical properties of the material. In addition, montmorillonite plays the role of nucleating agent during the crystallization of polypropylene, which improves the crystallization efficiency of polypropylene. After the organic modification of montmorillonite, the spacing between crystal surfaces can be enlarged to form organic montmorillonite, which makes the molecular chains of polypropylene more easily dispersed to the interlayer of organic montmorillonite, forming a dense surface layer in the process of thermal decomposition, so as to improve the thermal stability of polypropylene and enhance the flame retardant property of polypropylene. Many previous studies have shown that montmorillonite plays a significant role in improving the mechanical strength and crystallization effect of polypropylene, as well as the flame retardant properties of nanocomposites.

Reconstructable Carbon Monolayer-MoS2 Intercalated Heterostructure Enabled by Atomic Layers-Confined Topotactic Transformation for Ultrafast Lithium Storage.

The intercalation structure of two-dimensional materials with expanded interlayer distance can facilitate mass transport, which is promising in fast-charging lithium-ion batteries (LIBs). However, the designed intercalation structures will be pulverized and destroyed under tough working conditions, causing overall performance deterioration of the batteries. Here, we present that an intercalated heterostructure made of the typical layered material of MoS2 intercalated by N-doped graphene-like carbon monolayer (MoS2/g-CM) through a polymer intercalation strategy exhibits a unique behavior of reversible reconstructability as an LIB anode during cycling. A mechanism of "carbon monolayers-confined topotactic transformation" is proposed, which is evidenced by substantial in/ex situ characterizations. The intercalated heterostructure of MoS2/g-CM featuring a reconstructable property and efficient interlayer electron/ion transport exhibits an unprecedented rate capability up to 50 A g-1 and outstanding long cyclability. Moreover, the proposed strategy based on g-CM intercalation has been extended to the MoSe2 system, also realizing reconstructability of the intercalated heterostructure and improved LIB performance, demonstrating its versatility and great potential in applications.

Bimetallic Intercalated Vanadium Oxide As a High-Performance Cathode for Aqueous Zinc Ion Batteries.

In this paper, a bimetallic Na0.13Mg0.02V2O5·0.98H2O (NMVO) material with an interlayer spacing of 11.67 Å was synthesized by a simple preintercalation method as a cathode for zinc ionic batteries (ZIBs). The large layer spacing provides a wide channel for the embedding of Zn2+, resulting in high reversible capacity and ion diffusion kinetics. In addition, by virtue of the high electronic conductivity of metal ions, NMVO exhibits excellent electronic conductivity under the combined action of Na+ and Mg2+ bimetallic intercalation. At the same time, preintercalation ions and structural water act as interlayer pillars to stabilize the layer structure of NMVO during the cycling process. The above reasonable structural design endows the NMVO with excellent electrochemical performance. The battery with NMVO cathode delivers a high initial capacity of 126 mAh g-1 at 10 A g-1, and still remains at 76% after 5000 cycles, providing 100 Wh kg-1 energy density and 9.5 kW kg-1 power density (based on the mass of cathode). This bimetallic intercalation structure provides a general feasible scheme for the design of vanadium-based electrode materials.

Hybrid ion/electron interfacial regulation stabilizes the cobalt/oxygen redox of ultrahigh-voltage lithium cobalt oxide for fast-charging cyclability

High-voltage and fast-charging LiCoO2 (LCO) is key to high-energy/power-density Li-ion batteries. However, unstable surface structure and unfavorable electronic/ionic conductivity severely hinder its high-voltage fast-charging cyclability. Here, we construct a Li/Na-B-Mg-Si-O-F-rich mixed ion/electron interface network on the 4.65 V LCO electrode to enhance its rate capability and long-term cycling stability. Specifically, the resulting artificial hybrid conductive network enhances the reversible conversion of Co3+/4+/O2−/n− redox by the interfacial ion–electron cooperation and suppresses interface side reactions, inducing an ultrathin yet compact cathode electrolyte interphase. Simultaneously, the derived near-surface Na+/Mg2+/Si4+-pillared local intercalation structure greatly promotes the Li+ diffusion around the 4.55 V phase transition and stabilizes the cathode interface. Finally, excellent 3 C (1 C = 274 mA g−1) fast charging performance is demonstrated with 73.8% capacity retention over 1000 cycles. Our findings shed new insights to the fundamental mechanism of interfacial ion/electron synergy in stabilizing and enhancing fast-charging cathode materials.

Construction of Poly(butylene succinate)-Grafted Graphene Bionanocomposites: Intercalation Structure, Synergistic Thermal–Oxidative Stabilization Effect, and Hydrolytic Behavior

Construction of Poly(butylene succinate)-Grafted Graphene Bionanocomposites: Intercalation Structure, Synergistic Thermal–Oxidative Stabilization Effect, and Hydrolytic Behavior

Ultra-strong adsorption of organic dyes and antibiotic onto the alk-MXene/ZIF adsorbents with a specific intercalation structure

By in-situ growing tiny ZIF (ZIF-67/ZIF-8) particles on the interlayer and surface of alkalized MXene (alk-MXene), alk-MXene/ZIF adsorbents with specific intercalation structure and ultra-strong adsorption capacity for antibiotics and dyes are designed. The introduction of ZIF particles offers a larger specific surface area and more adsorption functional groups in alk-MXene/ZIF composites. Changing the additive amount of alk-MXene (1, 0.5 and 0.25 g) can effectively tune the adsorption properties and morphology of the composites. Herein, when the additive amount of alk-MXene is 0.5 g (sample S2) exhibits optimal adsorption performance with maximum adsorption capacities qm of 539.7, 1053.3 and 7111.3 mg g−1 for Congo Red (CR), Tetracycline (TC) and Malachite Green (MG). That is, too much (sample S1) or too little (sample S3) addition of the alk-MXene into the composites will suffer the performance degradation. Impressively, the composites show fast adsorption kinetics, strong recycling ability and powerful anti-interference capacity to multiple ions in contaminants. Benefiting from the intercalation structure, ZIF particles protect alk-MXene from being oxidized in air, making the composites exhibit excellent chemical stability. Typically, Sample S2 retains its stable microstructure and outstanding adsorption properties in air for 45 days. Also, the actual application of sample S2 is analyzed by filtering the adsorbates multiple times. Furthermore, it is demonstrated that the synergistic effects of electrostatic interaction, hydrogen bonding and π-π stacking lead to the excellent adsorption capacity of alk-MXene/ZIF composites. This study suggests that alk-MXene/ZIF can be regarded as a high-efficiency and promising adsorbent to remove organic dyes and antibiotics.

Efficient mineralisation and disinfection of neonicotinoid pesticides with unique ZnAl-LDH intercalation structure and synergistic effect of Cu2O crystalline surface

Photocatalysts based on crystallographic effects and visible light-driven tunable nanostructures have been confirmed as a novel, scalable, and easy-to-implement technology. The hydrothermal reaction serves as the main method of synthesis for its novelty, becoming a viable alternative to other complex physical and chemical processes. In this study, hydrothermal conditions' parameters were set for nanostructured Cu2O/ZnAl-LDH photocatalysts. The nanostructured I-scheme Cu2O/ZnAl-LDH photocatalysts were prepared with an intercalated morphology. The prepared photocatalysts became the most effective photocatalyst for mineralizing and degrading nitenpyram solution, achieved nearly complete degradation and exceptionally high mineralization values (>40%) after 210 min of reaction, and exerted some ex vivo antibacterial, sterilising effects and potential for treating waste leachate (removal = 78%). The synergistic effect of Cu2O/ZnAl-LDH with both crystalline surface effect and intercalation structure can lead to reusability, high stability, versatility, and excellent photocatalytic performance in mineralize neonicotinoid pesticides.

Comparison of Structural, Water-Retaining and Sorption Properties of Acrylamide-Based Hydrogels Cross-Linked by Physical and Chemical Methods.

Two series of hydrogels based on acrylamide and its copolymers with acrylonitrile and acrylic acid were synthesized by two cross-linking methods - chemical (using N,N'-methylene bis-acrylamide) and physical (using montmorillonite (MMT)) ones. The structure of the gels was characterized by Fourier Transform Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The swelling and sorption properties were analyzed as a function of both the monomer composition and the cross-linking method. The shift of the band corresponding to Si-O (995-1030 cm-1 ) confirmed the formation of intercalation structures for MMT-cross-linked gels. Moreover, physically cross-linked gels demonstrated a non-monotonic dependence of the swelling degree on the MMT concentration, and acrylamide-acrylic acid copolymer MMT-cross-linked gels showed pH sensitivity and the highest swelling degree of 150 g/g. The highest sorption capacity towards cadmium(II) ions was demonstrated by acrylamide-acrylic acid copolymer gels, both covalently cross-linked (30 mg/g) and MMT-cross-linked (8.9 mg/g).