Conventional Hydrogels Research Articles

Regulation of physicochemical properties of alginate-based hydrogels and preliminary applications in wound healing.

Alginate (Alg) hydrogels have demonstrated great potential in drug delivery, wound dressings, and tissue engineering. However, the practical applications of conventional Alg hydrogels suffer from rapid degradation, insufficient controlled drug release, and poor adhesion to tissues. In this paper, the physicochemical properties of Alg hydrogels were comprehensively modulated through chemical modification and the incorporation of various polymers. The results showed that introducing neutral polymers stabilized Alg hydrogels at room temperature. However, this stabilizing effect did not persist at 37 °C. The cationic chitosan (CS) can bind to Alg through electrostatic interaction. The incorporation of CS substantially improved the stability of Alg hydrogels and remarkably prolonged the release of BSA from hydrogels to 14 days at 37 °C. Meanwhile, introducing dopamine (DA)-modified Alg enhanced the adhesion of hydrogel to porcine skin. The optimized hydrogels were utilized to encapsulate platelet-rich plasma (PRP). The PRP-loaded composite hydrogel (2 wt% Alg, with a Ca2+/carboxyl group molar ratio of 0.2, a DA/carboxyl group molar ratio of 0.2, and a CS content of 30 % of Alg) exhibited an excellent therapeutic effect in the healing of rabbit shoulder cuff injury. These findings provide valuable insights into the modulation of physicochemical properties of hydrogels for biomedical applications.

Extended release of ciprofloxacin from commercial silicone-hydrogel and conventional hydrogel contact lenses containing vitamin E diffusion barriers.

Vitamin E could be used as a coating with commercial silicone hydrogel lenses to extend the release of various ophthalmic drugs. This concept could provide a promising approach to improve overall ocular therapeutic outcomes for topical ocular drugs. This study aimed to develop a contact lens-based ocular drug delivery system using vitamin E as a diffusion barrier to extend the release duration of ciprofloxacin. Five commercial lenses were soaked for 24 hours in various concentrations of vitamin E dissolved in ethanol (0.0125 to 0.2 g/mL). The lenses were loaded with ciprofloxacin for 24 hours in 3 mL of 3 mg/mL of ciprofloxacin/acetic acid solution. The drug release was evaluated in 3 mL of phosphate-buffered saline solution. At t = 0.5, 1, 2, 4, 6, 8, 12, 16, and 24 hours, the amount of ciprofloxacin released was measured using a UV-VIS spectrophotometer at 270 nm. There was a decrease in ciprofloxacin loading with increasing amounts of vitamin E loaded into the silicone hydrogel lenses. For each lens type, there was an optimal amount of vitamin E loaded that extended the release duration of the drug from 1 hour (without vitamin E) to as long as 16 hours. In contrast, vitamin E loaded into hydrogel lenses had no effect on the amounts of drugs loaded or the release duration. Vitamin E can be used as a diffusion barrier with commercially available silicone hydrogel lenses to provide sustained release of ciprofloxacin. The results suggest that vitamin E may form blockages in channels within a silicone hydrogel lens material, thereby forcing a longer path for drugs to diffuse into and out of the lens material. There is an optimal amount of vitamin E that needs to be loaded to extend the release duration, and this is lens material dependent.

Double network hydrogel confined MXene/Liquid metal by dynamic hydrogen bond for high-performance wearable sensors

Double-network (DN) hydrogels, which integrate long-chain and short-chain molecular structures, exhibit significant potential in wearable sensors due to their exemplary mechanical properties. However, conventional hydrogels often suffer from poor conductivity and low sensitivity. In this study, we develop a novel DN hydrogel (comprising polyacrylamide/sodium alginate) that encapsulates MXene (Ti3C2Tx) and liquid metal (LM). This configuration leverages the conductive properties of two-dimensional MXene and zero-dimensional liquid metal embedded within the DN hydrogel networks. The Ti3C2Tx MXene sheets enhance the binding capacity with LM by serving as a conductive bridge, thereby improving interfacial interactions and reducing hysteresis. The resultant strain sensor, fabricated from this composite DN hydrogel, achieves high sensitivity (gauge factor up to 12.84), a broad detection range (0 %-1500 %), rapid response time (262 ms), and excellent repeatability and stability. We have integrated this strain sensor into wearable flexible devices, such as contact lenses, enabling real-time monitoring of human physiological pressures.

Multi-functional Gleditsia sinensis galactomannan-based hydrogel with highly stretchable, adhesive, and antibacterial properties as wound dressing for accelerating wound healing

Design and development of a multifunctional wound dressing with self-healing, adhesive, and antibacterial properties to attain optimal wound closure efficiency are highly desirable in clinical applications. Nevertheless, conventional hydrogels face significant barriers in their mechanical strength, adhesive performance, and antibacterial properties. Herein, a tough hydrogel based on aldehyde-grafted galactomannan was synthesized through radical copolymerization and Schiff base reaction, incorporating hyaluronic acid, acrylamide, and the zwitterionic monomer to create a multi-crosslinked structure. The multiple crosslink structure pattern consisting of multiple hydrogen bonding, ionic interactions, reversible Schiff bases bonds, and molecular chain entanglement endowed this hydrogel with multiple functionalities, including high tensile strength (25 kPa), tensile strain (2200 %), toughness (391.59 kJ/m3), and Young's modulus (9.77 kPa). The presence of catechol groups and zwitterionic groups endow hydrogels with outstanding adhesion strength (42.21 kPa), which satisfied the adhesive demand for the ample motion of specific areas. The zwitterionic monomer provided long-lasting antibacterial properties and promoted migration and growth of negatively charged cells, capable of establishing efficient antibacterial barriers and serving as wound dressing. The in vivo and vitro experiments manifested that the optimized hydrogel demonstrated an inconspicuous inflammatory response, facilitating rapid healing of full-thickness skin wound in rat models. Therefore, this work provides a promising strategy and an ideal candidate for wound healing dressings in treating infected skin wounds.

A Review of Advanced Hydrogel Applications for Tissue Engineering and Drug Delivery Systems as Biomaterials

Hydrogels are known for their high water retention capacity and biocompatibility and have become essential materials in tissue engineering and drug delivery systems. This review explores recent advancements in hydrogel technology, focusing on innovative types such as self-healing, tough, smart, and hybrid hydrogels, each engineered to overcome the limitations of conventional hydrogels. Self-healing hydrogels can autonomously repair structural damage, making them well-suited for applications in dynamic biomedical environments. Tough hydrogels are designed with enhanced mechanical properties, enabling their use in load-bearing applications such as cartilage regeneration. Smart hydrogels respond to external stimuli, including changes in pH, temperature, and electromagnetic fields, making them ideal for controlled drug release tailored to specific medical needs. Hybrid hydrogels, made from both natural and synthetic polymers, combine bioactivity and mechanical resilience, which is particularly valuable in engineering complex tissues. Despite these innovations, challenges such as optimizing biocompatibility, adjusting degradation rates, and scaling up production remain. This review provides an in-depth analysis of these emerging hydrogel technologies, highlighting their transformative potential in both tissue engineering and drug delivery while outlining future directions for their development in biomedical applications.

Self-Healable Hydrogels from Vegetable Oil: Preparation, Mechanism, and Applications.

Hydrogels are indispensable for a variety of applications. Conventional biomaterial-based hydrogels, typically made from proteins or polysaccharides, often suffer from high costs, poor mechanical properties, and limited chemical functionality for modification. In this work, we present a novel hydrogel developed from modified castor oil, which is a renewable and cost-effective resource. Castor oil-based oligomer (CG) was synthesized using glycidyl methacrylate and triethylamine via ring-opening polymerization. The oligomer formed a gel only with Cu2+ ions among the various systematically studied metal ions. Comprehensive density functional theory calculations, atoms in molecules analysis, and steady and dynamic shear rheology were conducted to investigate the metal-binding sites and metal-oligomer interactions as well as the self-healing and viscoelastic properties of the oil-based hydrogels. The hydrogel exhibited 94% self-healing efficiency and performed as a recyclable rhodamine B dye adsorbent (73-90%). This innovative approach offers a novel, cost-effective, and sustainable alternative to traditional hydrogels, paving the way for advanced applications.

Congelation- and dehydration-tolerant, mechanically robust hydrogel electrolyte for durable iontronic sensors operating in open air and freezing temperatures over wide strain and pressure ranges

Conventional hydrogels have limitations in mechanical properties and are susceptible to loss of elasticity and conductivity caused by congelation and dehydration, limiting their practical uses for application in high-stress environments, open air, and freezing temperatures. This study introduces a mechanically robust, dehydration- and congelation-tolerant, and ionically conductive hydrogel electrolyte, practical for iontronic sensors working in wide pressure and strain ranges under open-air and freezing temperatures. This hydrogel electrolyte is fabricated through a reconstruction process comprising a drying-induced densification of double-network hydrogel of alginate and polyacrylamide, a structure fixation by Fe3+ crosslinking, and a Li+ infiltration. The resultant hydrogel electrolyte is tolerant to dehydration and congelation and mechanically robust, with strength and elastic modulus of a few mega-pascals comparable to those of non-conductive elastomers/rubbers used as dielectric materials. Therefore, the hydrogel electrolyte-based iontronic sensors demonstrate exceptional sensitivity and stability under compression and tension and across a wide temperature range. Further, the sensor demonstrates their practical applicability in high-stress environments from kg-range human weight to ton-range car weight. These achievements evince that iontronic sensors, based on mechanically robust and ionically conductive hydrogel electrolytes tolerant to congelation and dehydration, can be employed for practical applications.

Preparation and application of organic hydrogels incorporating polyacrylamide/sodium alginate/DMSO for enhanced anti-drying, anti-freezing, and self-healing properties

The double-network hydrogel comprises two asymmetrically structured cross-linked networks, demonstrating exceptional mechanical properties and possessing significant potential for application in the field of flexible sensors. However, conventional hydrogels primarily disperse in water as a medium and continuously lose moisture in natural environments, rendering them incapable of retaining hydration over extended periods and unsuitable for utilization under low-temperature conditions. In this study, we devised an organic hydrogel based on polyacrylamide (PAM), sodium alginate (SA), and dimethyl sulfoxide (DMSO). Through hydrogen bonding interactions among DMSO molecules, polyacrylamide, and sodium alginate, this organic hydrogel not only exhibits anti-drying and anti-freezing properties but also demonstrates self-healing characteristics. Moreover, the organic hydrogel showcases remarkable mechanical properties and conductivity capabilities that render it suitable for constructing flexible strain sensors to monitor human movements such as finger bending, elbow flexion, knee joint bending, and ankle extension. Additionally, the sensor exhibits excellent stability and durability.

Stabilization of Picea abies Spruce Bark Extracts within Ice-Templated Porous Dextran Hydrogels.

Porous hydrogels have brought more advantages than conventional hydrogels when used as chromatographic materials, controlled release vehicles for drugs and proteins, matrices for immobilization or separation of molecules and cells, or as scaffolds in tissue engineering. Polysaccharide-based porous hydrogels, in particular, can address challenges related to bioavailability, solubility, stability, and targeted delivery of natural antioxidant compounds. Their porous structure enables the facile encapsulation and controlled release of these compounds, enhancing their therapeutic effectiveness. In this context, in the present study, the cryogelation technique has been adopted to prepare novel dextran (Dx)-based porous hydrogels embedding polyphenol-rich natural extract from Picea abies spruce bark (SBE). The entrapment of the SBE within the Dx network was proved by FTIR, SEM, and energy-dispersive X-ray spectroscopy (EDX). SEM analysis showed that entrapment of SBE resulted in denser cryogels with smaller and more uniform pores. Swelling kinetics confirmed that higher concentrations of Dx, EGDGE, and SBE reduced water uptake. The release studies demonstrated the effective stabilization of SBE in the Dx-based cryogels, with minimal release irrespective of the approach selected for SBE incorporation, i.e., during synthesis (~3-4%) or post-synthesis (~15-16%). In addition, the encapsulation of SBE within the Dx network endowed the hydrogels with remarkable antioxidant and antimicrobial properties. These porous biomaterials could have broad applications in areas such as biomedical engineering, food preservation, and environmental protection, where stability, efficacy, and safety are paramount.

Superhydrophobic and super-stretchable conductive composite hydrogels for human motion monitoring in complex condition

With the advent of the information age, there is a growing demand for wearable sensing devices. Conventional hydrogels are a class of materials that can hold a large amount of water, with a three-dimensional network of hydrophilic polymerization chains inside. In remote areas or harsh environments, there is an urgent demand for a flexible sensor that is environmentally stable, wearable, and has high mechanical properties. Due to the hydrophilicity of the traditional hydrogel surface, it is easy to adsorb dust or be contaminated by liquid, which limits its further application. As a result, the superhydrophobic hydrogel F-PTD was designed using SiO2@PDA, F-HNT and PT hydrogel. TGA, XPS, SEM, FT-IR was used to characterize the structure of F-PTD, respectively. Based on the study of mussels, the adhesion property of polydopamine was utilized as an adhesion agent between organic–inorganic interfaces while improving the roughness of the hydrogel surface. The fabricated F-PTD superhydrophobic conductive hydrogels have excellent stretchability (Tensile Strain > 500 %), stable hydrophobicity (CA > 150°), and sensitive electrical conductivity (GF = 3.49). The contact angle of F-PTD is greater than 150° for tensile strains in the range of 0–350 %, and it maintains superhydrophobic under corrosive solutions with pH = 1–14. This enables F-PTD to perform the sensing function of detecting human body signals under complex environmental conditions, which has great potential for application in the field of underwater rescue, wearable electronics and human–computer interfaces.

Wet stability soft skin electronic sensor based on biochar-polypyrrole conductive hydrogel

Hydrogels have the softness and stretchability of similar tissues and are considered as materials for smart flexible electronic devices. However, the durability and reliability of most polypyrrole hydrogels in wet environments are still insufficient, especially its wet stability in the wet environment of seawater, limiting its development as flexible conductive electrodes. In this study, the porous solid carbon material after pyrolysis of natural materials is introduced into hydrogel, which is conducive to the migration and propagation of electrolyte ions, and can improve the moisture resistance stability of hydrogel. At the same time, polypyrrole material is introduced to further improve its electrical conductivity. With this method, the conductivity of conventional hydrogel materials can be increased by 12.2 times. The triboelectric nanogenerator device prepared with polypyrrole/biochar composite hydrogel can not only accurately monitor human joint motion, but also easily light up at least 300 light-emitting diodes when rubbed with aluminum materials, which proves the practical performance of the device. This study provides an alternative material for sensing hydrogels that can be used for human health monitoring of marine operators.

Lignin-modified cellulose nanofibers hydrogel under adjustable binary solvent systems with excellent adhesion, self-healing and anti-freeze properties

Hydrogels with remarkable flexibility have gained popularity as materials for current research. However, the unfavorable properties of short-term adhesion, susceptibility to damage, and freezing in low-temperature presented by conventional hydrogels have become bottlenecks for further applications. In this work, an anti-freezing hydrogel with excellent mechanical, adhesion, and self-healing properties were developed by constructing a persistent semiquinone/quinone-catechol redox equilibrium environment. The introduction of lignin-modified cellulose nanofibers (LCNFs) significantly improved the overall mechanical properties of the material, driven by strong hydrogen bond interactions. This enhancement was evident in the tensile properties (97.74 ± 1.72 kPa, 783 %) and compression properties (> 90 %). Within the internal network of the gel, the synergistic action of lignin and ammonium persulfate resulted in the production of catechol, which imparted the gel with excellent adhesion properties (28.26 ± 2.13 KPa) and broad adhesion applicability. In addition, the incorporation of ethylene glycol (EG) positively contributed to the strengthening of the gel while endowed with tunable anti-freezing properties. Given the exceptional advantages of the prepared hydrogels, they were used to assemble flexible strain sensors with outstanding sensitivity for monitoring human motions.

Preparation of Gradient HEA-DAC/HPA Hydrogels by Limited Domain Swelling Method.

Hydrogels are widely used in biological dressing, tissue scaffolding, drug delivery, sensors, and other promising applications owing to their water-rich soft structures, biocompatibility, and adjustable mechanical properties. However, most of the conventional hydrogels are isotropic. The anisotropic structures existed widely in the organizational structure of plants and animals, which played a crucial role in biological systems. In this work, a method of limited domain swelling to prepare anisotropic hydrogels is proposed. Through spatially controlled swelling, the extension direction of hydrogels can be limited by a tailored mold, further achieving anisotropic hydrogels with concentration gradients. The external solution serves as a swelling solution to promote swelling and extension of the hydrogel matrix in a mold which can control the extension direction. Due to the diversity of external solutions, the method can be applied to prepare a variety of stimulus-responsive polymers. The limited domain swelling method is promising for the construction of anisotropic hydrogels with different structures and properties.

Supercooling-Driven Homogenization and Strengthening of Hydrogel Networks.

By leveraging principles from metal grain refinement, we introduce a transformative technique for fabricating poly(vinyl alcohol) (PVA) hydrogels via supercooling-coupled wet annealing, significantly enhancing their mechanical robustness and isotropy while maintaining their exceptionally high water content. Our methodology involves the dissolving PVA in water at elevated temperatures, mirroring the homogeneity achieved with a molten metal, in order to ensure a uniform distribution of polymer chains. This uniformity facilitates a rapid cooling phase that generates ultrafine ice crystals, setting the stage for a crucial solvent exchange with ethylene glycol (EG). The EG-mediated supercooling technique ensures the polymer homogeneity and structure integrity and induces the PVA chains to aggregate and form high-density hydrogen bonds, leading to a uniformly distributed, interconnected PVA network with high crystallinity. The process is further strengthened by EG-enabled wet annealing, which promotes the formation of densely packed crystalline domains within the polymer network. This rigorous process yields PVA hydrogels with superior mechanical properties, including a tensile strength of 13.65 MPa and a fracture toughness of 35.39 MJ m-3, alongside remarkable water content nearing 80%. These advances not only surpass the capabilities of conventional hydrogels but also broaden their application potential, highlighting the innovative integration of supercooling principles in polymer science.

Gallic acid melanin pigment hydrogel as a flexible macromolecule for articular motion sensing

In this study, water-soluble melanin was synthesized through the genetic recombination of Escherichia coli using gallic acid as a substrate. The recombinant host produced 2.83 g/L of gallic acid-based melanin (GA melanin) from 20 mM gallic acid. Notably, the isolated GA melanin demonstrated exceptional antioxidant and antimicrobial activities, exhibiting a 25.7 % inhibition ratio against Candida albicans. The structure and composition of GA melanin were analyzed using Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and X-ray diffraction (XRD). Remarkably, GA melanin displayed high thermal stability, maintaining integrity up to 1000 °C. Additionally, it exhibited unique electrical properties in terms of conductivity and resistivity compared to other common types of melanin. Subsequently, GA melanin was cross-linked with hydrogel to create a sensing template. The resulting GA melanin hydrogel demonstrated lower resistance (80.08 ± 3.0 kohm) compared to conventional hydrogels (108.62 ± 10.4 kohm), indicating an approximately 1.77-fold improvement in adhesion. Given its physical, biological, and electrical properties, the GA melanin hydrogel was further utilized as a flexible motion-sensing material to detect resistivity changes induced by knee, wrist, and finger bending, as well as vocal cord vibrations. In all cases, the sensing module displayed notable sensitivity to motion-induced resistivity variations.

Facile strategy of Fe3+ rich collagen-based composite hydrogel for antibacterial, electricity harvesting and sensing applications

Conventional hydrogels have poor conductivity and low stretchability, limiting their practical applications for different purposes. Herein, collagen (CL) based, poly(vinyl alcohol) (PVA) and glutaraldehyde (GT) cross-linked ferric ion (Fe3+) rich highly conductive CL/GT/PVA/Fe hydrogel was developed. The presence of high CL, PVA and Fe3+ ions, together with the effective Fe3+ complexes formation, delivers the hydrogel with some particular assigns, such as high ionic conductivity (3.44 S.m−1) and antibacterial activity; furthermore, a very high stretchability. The CL/GT/PVA/Fe hydrogel demonstrated excellent mechanical properties, where the highest tensile strength of the hydrogels was ∼204.5 kPa at an elongation of 674 %, and the highest compressive strength was ∼0.39 MPa, with the highest stretchability of 81.67 %. The strengths are enhanced significantly by the incorporation of Fe3+ ions because of the formation of effective complexation of Fe3+ with rich hydroxyl and carboxyl groups of PVA and CL. As a flexible strain sensor, the CL/GT/PVA/Fe hydrogel with excellent conductivity manifests high sensitivity in human motion monitor. The hydrogels’ sufficient –OH and –COOH groups play a key role in imparting moist-induce electricity supply and the highest 173 mV of open circuit voltage (Voc) generated during moisture spray.

Lignin hydrogel sensor with anti-dehydration, anti-freezing, and reproducible adhesion prepared based on the room-temperature induction of zinc chloride-lignin redox system

In recent years, flexible sensors constructed mainly from hydrogels have received increasing attention. However, conventional hydrogels need to be prepared by high-temperature or radiation-induced polymerization reactions, which limits their practical applications due to their suboptimal electrical conductivity and weak mechanical properties. In this paper, using sodium lignosulfonate as the raw material, a dynamic catechol-quinone redox system formed by lignin‑zinc ions was constructed to initiate rapid free radical polymerization of acrylamide (AM) monomer at room temperature. In addition, Deep eutectic solvent (DES) can form a strong hydrogen bonding network within the molecules and between the molecules of the hydrogel, resulting in a hydrogel with good tensile properties (hydrogel elongation at break of 727.19 %, breaking strength of 84.09 kPa), and provides the hydrogel with high electrical conductivity, anti-dehydration, anti-freezing, and anti-bacterial properties. Meanwhile, the addition of lignin also improved the adhesion and UV resistance of the hydrogel. This hydrogel assembled into a flexible sensor can sense various small and large amplitude movements such as nodding, smiling, frowning, etc., and has a wide range of applications in flexible sensors.

Strong and anti-swelling nanofibrous hydrogel composites inspired by biological tissue for amphibious motion sensors.

Conductive hydrogel-based sensors are increasingly favored for flexible electronics due to their skin-like characteristics. However, conventional hydrogels suffer from significant swelling in humid environments and poor mechanical properties which largely restrict their applications in wearable electronic devices, especially for underwater sensing. Herein, drawing inspiration from the extracellular matrix (ECM) structure, a TPU-PVAc@AgNPs/MXene nanofibrous hydrogel composite (TPAMH) with excellent mechanical robustness and anti-swelling properties is developed. The TPAMH nanofibrous hydrogel composite is created by integrating the silver nanoparticles (AgNPs) and MXene nanosheets into an interwoven network comprising of stiff TPU nanofibers as the fibril scaffold and formic acid-crosslinked PVA hydrogel fibers as the elastic matrix (PVAc). Benefiting from the unique ECM structure, the obtained nanofibrous hydrogel composites exhibit exceptional tensile strength (4.47 MPa), remarkable elongation at break (621%), excellent anti-swelling properties, and high detection sensitivity (maximum gauge factor = 105.02), which are sufficient to monitor body motions in both air and water environments effectively. They can detect large strain movements of fingers, elbows, wrists, and knees, as well as small strain physiological signals such as frown, smile, and pulse beats, with high accuracy. Particularly noteworthy is their ability to accurately identify underwater multidirectional motions and facilitate underwater smart alarms using Morse code.

Injectable decellularized extracellular matrix hydrogel with cell-adaptable supramolecular network enhances cartilage regeneration by regulating inflammation and facilitating chondrogenesis

Osteoarthritis, characterized by progressive loss of cartilage, affects millions of people worldwide and clinically lacks effective treatments. Herein, we present an injectable, biodegradable supramolecular decellularized extracellular matrix (dECM) hydrogel, which can be injected into the joints and provide biomimetic microenvironments to drive cartilage regeneration. Benefiting from the cell-adaptable dynamic network and cartilage-specific compositions, the supramolecular dECM hydrogel not only enhances cell proliferation and migration, but also facilitates chondrogenesis. Furthermore, compared with the conventional dECM hydrogels, the supramolecular dECM hydrogel is instrumental in regulating inflammation, which consequently leads to a marked suppression of genes linked to cell death and cartilage degradation. In vivo analysis confirms that stem cells, when delivered via the supramolecular dECM hydrogel, remain viable for up to three months within the restored cartilage. The regenerated tissue exhibits hyaline-cartilage structure, good mechanical properties, and cartilage-specific extracellular matrix deposition that align closely with those of native cartilage. We envision that this supramolecular dECM hydrogel could serve as a valuable platform for cartilage regeneration and could strongly facilitate the clinical translation of dECM-based materials for tissue regeneration.

Design of hybrid multi-crosslinked hydrogel with a combination of high stiffness, elastic applied in high temperature and high salinity reservoirs

The mechanical strength of conventional hydrogels is inadequate for preventing leakage in high-temperature and high-salinity reservoirs, primarily due to the increased mobility of polymer chains and the degradation of crosslinked networks. Herein, we employed the strategy of ’network nesting and layer reinforcement’ to design a hybrid multi-site crosslinked hydrogel. This approach enhances the interconnections between polymer chains and fortifies the crosslinked network. The shear rheological behavior and temperature sensitive characteristics of the profile control working fluids were evaluated based on rheological dynamics. In the high temperature (140 ℃) and high salinity (21.81 × 104 mg/L) preparation environment, the effects of different components to the mechanical strength of the hydrogel were investigated under dynamic shear and uniaxial compression conditions. The incorporation of N-(hydroxymethyl)acrylamide (NMA) in the copolymerization with acrylamide (AM) resulted in an increase in the covalent cross-linking density, leading to a rise in the shear elastic modulus from 105 Pa to 238 Pa. The use of pre-gelatinized cassava starch (PGCM) as the grafting framework enhanced the bonding between the polymer chains, as evidenced by the increase in uniaxial compressive strength from 0.018 MPa to 0.081 MPa and the rise in peak strain from 55.0 % to 72.9 %. Furthermore, the synergistic effect of fumed silica (AEROSIL), which exploits mechanical coupling between inorganic nano-fillers and organic polymers, increased the compressive strength from 0.081 MPa to 0.418 MPa and raised the peak strain from 72.9 % to 81.8 %. It provides an effective approach to enhance the plugging performance of hydrogels in high temperature and high salinity reservoirs.