Alcohol Composite Hydrogel Research Articles

Enhancing refrigerated chicken breasts preservation: Novel composite hydrogels incorporated with antimicrobial peptides, bacterial cellulose, and polyvinyl alcohol

Microbial contamination annually leads to substantial food resource loss. Effective food packaging can mitigate food contamination and waste, yet conventional materials such as plastics often lack bacteriostatic activity. This study aimed to synthesise FengycinA-M3@bacterial cellulose@polyvinyl alcohol composite hydrogels via dual cross-linking with hydrogen and borate bonding, with the goal of enhancing antibacterial properties and prolonging the preservation period of refrigerated chicken breast. The composite hydrogel was subjected to comprehensive characterisation for structural, mechanical, water absorption, slow peptide release, antimicrobial capacity, biocompatibility, and chicken breast freshness preservation. The results showed that the composite hydrogel had a porous network structure and excellent gel elasticity and biocompatibility. It was effective in inhibiting Staphylococcus aureus and Escherichia coli, and prolonged the storage time of frozen chicken breast for up to 12 days. These findings emphasise the potential of hydrogel food packaging to prolong storage periods and its suitability for food industry applications due to ease of manufacture.

Sustainable solution for wastewater management: Fabrication of cost-effective β-cyclodextrin incorporated chitosan polyvinyl alcohol composite hydrogel film for the efficient adsorption of anionic congo red and tartrazine dyes

Dyes are an integral part of leather, textiles, food, and packaging materials, providing aesthetic appeal to the finished article. These industries use large amounts of water, creating wastewater with harmful, toxic, and hazardous pollutants, posing significant health and environmental risks to the public and ecological system. Therefore, to resolve this issue, a superabsorbent β-cyclodextrin incorporated chitosan polyvinyl alcohol cross-linked with citric acid composite hydrogel film (β-CD/Ch/PVA) has been developed for the effective adsorption of congo red (CR) and tartrazine dyes (TG). The Fourier-transform infrared spectroscopic (FTIR) analysis confirmed the presence of –OH, –NH2 functional groups in hydrogel film. The rough surface morphology was obtained through Field emission scanning electron microscopic (FESEM) analysis. Brunauer-Emmett-Teller (BET) method gave the surface area of hydrogel, which is 17.34 m2/g with pore diameter of 4.12 nm, indicating its mesoporous nature. Adsorption parameters like contact time, temperature, pH, initial concentration of dyes, and dosage of hydrogel have been optimized by batch adsorption studies and the Box-Behknen Design Model. In batch experiments, the hydrogel film effectiveness was confirmed, achieving high removal efficiencies of 95.38 % and 96.3 % for CR and TG dyes at pH 7 and 6, respectively. The adsorption process followed the pseudo-second-order kinetics and Langmuir model at room temperature for both dyes, and the maximum adsorption capacity was found to be 366.34 mg/g, 1436.04 mg/g for CR and TG dyes, respectively. The thermodynamic study revealed that the adsorption of dyes was spontaneous and endothermic in nature. The electrostatic interactions and hydrogen bonding between the hydrogel and dye molecules were responsible for the adsorption. This hydrogel film can be reused for 5 consecutive adsorption–desorption cycles for both dyes, maintaining upto 85 % in removal efficiency. Hence, the synthesized β-cyclodextrin incorporated chitosan polyvinyl alcohol composite hydrogel film holds great potential for the remediation of wastewater effluents and addressing environmental issues.

Constructing multifunctional polyvinyl alcohol composite hydrogels with human-like skin properties using polyaniline-coated boron nitride nanofibers

Flexible conductive nanofibers play a crucial role in constructing hydrogels with human-like skin properties. However, it is still a challenge to construct flexible conductive nanofibers with good comprehensive properties. In this paper, we prepare composite fibers with excellent comprehensive properties by coating polyaniline (PANI) on the surface of flexible boron nitride nanofiber (BNNFs) template. BNNFs-PANI/PVA multifunctional composite hydrogels are created through the integration of BNNFs-PANI as nanofillers with soft poly (vinyl alcohol) (PVA) matrix using a one-pot self-assembly method. The composite hydrogels exhibit outstanding plasticity, self-adhesion, and self-healing properties, with a self-healing efficiency reaching up to 96% within 120 s. Furthermore, the tensile strength of the composite hydrogels has been enhanced by 36%, with the elongation at break exceeding 1500%. The compressive strength of the composite hydrogels at 60% strain is increased by 62%. Beyond these mechanical and self-healing features similar to human skin, the composite hydrogels also can serve as electronic pen for painting on a touchable electronic screen, simulating the function of human skin. Moreover, the dynamic changes in the abundant conductive network contribute to the composite hydrogels’ high strain sensitivity. Compared with pure PVA hydrogels, it is improved by 29%. Notably, the strain sensitivity of the composite hydrogels is higher than that of most reported hydrogel sensors. Therefore, the composite hydrogels also can be employed as a real-time human motion sensor, capable of detecting and distinguishing various human movements. We believe that employing BNNFs as templates for crafting highly flexible and conductive nanofibers will foster the advancement of flexible conductive nanomaterials with comprehensive properties. Furthermore, the outstanding properties of the prepared composite hydrogels contribute to the ongoing development of conductive hydrogels with skin-like functionalities.

Continuous dual-network alginate hydrogel fibers with superior mechanical and electrical performance for flexible multi-functional sensors

Hydrogel fibers play a crucial role in the design and manufacturing of flexible electronic devices. However, continuous production of hydrogel fibers with high strength, toughness, and conductivity remains a significant challenge. In this study, ion-conductive sodium alginate/polyvinyl alcohol composite hydrogel fibers with an interlocked dual network structure were prepared through continuous wet spinning based on the pH-responsive dynamic borate ester bonds. Owing to the interlocked dual network structure, the resulting hydrogel fibers integrated superior performance of strength (4.31 MPa), elongation-at-break (>1500 %), ion conductivity (17.98 S m−1) and response sensitivity to strain (GF = 3.051). Benefiting from the excellent performance, the composite hydrogel fiber could be applied as motion-detecting sensors, including high-frequency, high-speed reciprocating mechanical motion, and human motion. Furthermore, the superior compatibility for human-computer interaction of the hydrogel fiber was also demonstrated, which a manipulator could be controlled to perform different actions, by a smart glove equipped with the hydrogel fiber sensors.

Polypropylene mesh coated with hyaluronic acid/polyvinyl alcohol composite hydrogel for preventing bowel adhesion

Polypropylene (PP) mesh is the most widely used prosthetic material in hernia repair. However, the efficacy of implanted PP mesh is often compromised by adhesion between viscera and PP mesh. Thus, there is a recognized need for developing an anti-adhesive PP mesh. Here, a composite hydrogel coated PP mesh with the prevention of adhesion after hernia repair was designed. The composite hydrogel coating was prepared from polyvinyl alcohol (PVA) and hyaluronic acid (HA) by using the freezing-thawing (FT) method. To overcome the shortcoming of the long time of the traditional freezing-thawing method, a small molecule 3,4-dihydroxyphenylacetic acid (DHPA) was introduced to promote the formation of composite hydrogel. The as-prepared composite hydrogel coating displayed modulus more closely resembling that of native abdominal wall tissue. In vitro studies illustrated that the resulting meshes showed excellent coating stability, hemocompatibility, and non-cytotoxicity. In vivo experiments using a rat abdominal wall defect model demonstrated that the composite hydrogel coated PP mesh could prevent the formation of adhesion, alleviate the inflammatory response, and reduce the deposition of collagen around the damaged tissue. These disclosed results manifested that the PP mesh coated with HA/PVA composite hydrogel might be a promising application in preventing adhesion for hernia repair.

Highly conductive and sensitive acrylamide-modified carboxymethyl cellulose/polyvinyl alcohol composite hydrogels for flexible sensors

Conductive hydrogels were of interest as ideal materials for devices in the field of flexible sensing due to their mechanical flexibility and high electrical conductivity; however, conventional conductive hydrogels failed in high toughness, high electrical conductivity, and high recyclability at the same time and have not been widely used. Herein, we reported the used of carboxymethyl cellulose (CMC) and polyacrylamide (PAAM) grafts to form a hydrogel with polyvinyl alcohol (PVA), and the introduction of the conductive polymers polyaniline (PANI) and zinc ions (Zn2+) to obtain PANI/CMC-Zn2+-PAAM/PVA composites. The results showed that the breaking elongation of PANI/CMC-Zn2+/PAAM/PVA hydrogel was 183% and the conductivity was 1.32 S m−1 due to the interaction of chemical covalent bonds and physical crosslinking between molecules. As a wearable strain sensor, the PANI/CMC-Zn2+/PAAM/PVA hydrogel had an impressive sensitivity (GF=2.09 for a tensile strain range of 0%- 80% and GF=4.58 for a tensile strain range of 80%-120%), which can be used for detecting the signals of motion and physiological activities in various parts of the human body. This research will provide a valuable way for the application of hydrogel sensors in the fields of visual human-computer interaction, wearable sensors, visual optical detection and medical health detection.

Algal cellulose reinforced polyvinyl alcohol composite hydrogel with controlled niacinamide release for cosmeceutical applications

Niacinamide, a multi-functional cosmeceutical ingredient, has been extensively formulated in skincare products. To enhance the efficacy of niacinamide penetration into the skin, numerous hybrid hydrogels and drug delivery systems have been extensively developed as carriers for efficient entrapment and release of niacinamide. However, the mechanical properties and limited capacity of achieving high loading and sustained drug release are predominantly determined by synthetic polymers. Hence, it becomes imperative to develop innovative hybrid materials. Here, we successfully fabricated algal cellulose/Polyvinyl alcohol (PVA) composite hydrogels by employing cellulose extracted from Cladophora spp. and Ulva spp. through alkaline treatment. The physiochemical characteristics and properties of the composite hydrogels including niacinamide entrapment and release efficiency were examined. The results found that reinforcing PVA with algal cellulose resulted in a reduction in pore size with an increase in both number and distribution. The reinforcement also led to enhanced thermal stability and improved swelling properties. The Ulva cellulose/PVA composite hydrogel exhibited a higher swelling ratio and encapsulation efficiency compared to Cladophora cellulose/PVA composite hydrogel. Furthermore, the results of release kinetics confirmed that the Ulva cellulose/PVA composite hydrogel showed the most effective mechanism of niacinamide release from hydrogel, transitioning from non-Fickian to Fickian model. This suggests that it is a suitable material for niacinamide delivery as a cosmeceutical ingredient via the transdermal route. This study implies that the Ulva cellulose/PVA composite hydrogel could serve as a promising vehicle for niacinamide delivery across the skin.

Effects of charge state of nano-chitin on the properties of polyvinyl alcohol composite hydrogel

The present work investigates the effects of nano-chitin with different charge, obtained by acid hydrolysis and TEMPO oxidation, on the structure and properties of borax crosslinked polyvinyl alcohol (PVA) hydrogels. In detail, nano-chitin prepared by acid hydrolysis (ACh) is positively charged (+28.8 mV). The electrostatic attraction between ACh and borax ions leads to a maximum tensile stress of composite hydrogel (ACh/PB), 54.25 KPa, 17 times of the borax crosslinked PVA (PB). In contrast, nano-chitin prepared by TEMPO-oxidation (TCh) shows negative charge (−59.0 mV). Due to the electrostatic repulsion with borax ions, the maximum tensile stress of composite hydrogel (TCh/PB) is only 9.25 KPa, a very limit reinforcing effect. However, TCh/PB showed better self-healing efficiency (96.0 %) as well as ionic conductivity (1.25 × 10−5 S/m). The present work shows that the charge state of the nano-chitin exerts great influence on the interaction with the crosslinking agent borax, therefore, affects the structure and properties of the final PVA composite hydrogels. The results could provide important information about making full use of nano-chitin as a reinforcement by adjusting its surface charge state.

Electrospun of polyvinyl alcohol composite hydrogel nanofibers prepared by in-situ polymerization: A novel approach to fabricate hydrogel nanofiber membrane for lithium-ion batteries

The increasing demand for high-performance lithium-ion batteries has propelled the exploration of advanced materials to overcome limitations associated with commercially available polyolefin-based separators. This study introduces a pioneering approach involving the synthesis of a crosslinked hydrogel nanofiber membrane (PDs) composed of polyvinyl alcohol (PVA) and N, N-dimethylacrylamide (DMAAm) through the combination of the photo-polymerization with electrospinning process. To address key drawbacks observed in existing separators—namely, low porosity, inadequate thermal stability, and insufficient electrolyte wettability—the porosity of the PDs hydrogel nanofibers was systematically controlled through both heating drying (PD12-HD) and freeze-drying (PD12-FD) methods. The separator’s properties and performance were thoroughly examined, focusing on its chemical, mechanical, thermal, swelling, morphological, conductivity, and electrochemical properties. Comprehensive characterization of the PD12-FD separator revealed remarkable attributes surpassing those of a commercial counterpart (Celgard). The PD12-FD separator demonstrated exceptional mechanical strength (16.3 MPa), robust thermal stability (no shrinkage or deformation at 170 °C), high porosity (84.66 %), substantial electrolyte uptake capacity (672.86 %), superior ionic conductivity (3.405 mS/cm), and high lithium-ion transfer number (tLi+ = 0.678). The improvement is attributed to the cross-linked structure formed between PVA and DMAAm. Importantly, coin cells assembled with the PD12-FD separator exhibited outstanding electrochemical performance. Even after 150 cycles at 1C, the PD12-FD separator maintained a capacity above 95 % (145.48 mAh/g), surpassing both PVA and Celgard separators. This study proposes a novel methodology for fabricating hydrogel nanofiber separators and introduces a customizable synthesis approach for producing separators with enhanced performance and controlled characteristics.

Injectable alginate-based in situ self-healable transparent hydrogel as a vitreous substitute with a tamponading function

Retinal detachment and other vision-threatening disorders often necessitate vitreous body removal and tamponade injection for retina stabilization. Current clinical tamponades such as silicone oil and expansile gases have drawbacks, including patient discomfort and the need for secondary surgery. We introduce a transparent alginate-phenylboronic acid/polyvinyl alcohol composite hydrogel (TALPPH) as a novel vitreous substitute with tamponading capabilities. In vitro physicochemical, rheological, and optical characterization of in situ self-healable TALPPH was performed, and long-term biocompatibility was assessed in a rabbit model of vitrectomy retinal detachment. In vivo evaluations confirmed TALPPH's ability to inhibit retinal detachment recurrence and preserve rabbit vision without adverse effects. TALPPH's close resemblance to the natural vitreous body suggests potential as a vitreous tamponade substitute for future ophthalmological applications.

Preparation and characterization of carboxymethyl chitosan/polyvinyl alcohol composite hydrogel with improved mechanical and antibacterial properties

Biopolymer-based antibacterial hydrogels have attracted considerable interest in biomedical field. Herein, we report on an effective strategy for the preparation of carboxymethyl chitosan/polyvinyl alcohol (CMCh/PVA) composite hydrogel with improved mechanical and antibacterial properties by using poly(ethylene glycol) diglycidyl ether (PEGDE) as crosslinking agent and zinc acetate (ZnAc2) as catalyst, respectively. FT-IR and gelation time measurements confirm that the introduction of both PVA and ZnAc2 can accelerate the formation of ester bonds between CMCh and PEGDE. SEM images reveal the interconnected macroporous inner architecture in the current CMCh/PVA composite. While the hydrogels exhibit pH-sensitive swelling behaviors in the pH range from 3 to 11, they remain relatively stable in phosphate buffered saline buffer. Compression mechanical tests show that, when increasing the PVA concentration to 1.0%, the resultant CMCh/PVA composite hydrogel shows a compressive strength of 1.96 MPa. The dried composite sample prepared with 1.0% PVA has a water absorption capacity of 1860%. The antibacterial activities of the CMCh/PVA hydrogel are studied against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus by inhibition zone method, indicating that the composite hydrogel exhibits improved antibacterial activity after the adsorption of zinc ions.

Carbon black-containing self-healing adhesive hydrogels for endoscopic tattooing

Endoscopic tattooing with India ink is a popular method for identifying colonic lesions during minimally invasive surgery because it is highly challenging to localize lesions during laparoscopy. However, there is a perceived unmet need for the injection of India ink and carbon particle suspension due to various complications and inconstant durability during the perioperative period. In this study, carbon black-containing self-healing adhesive alginate/polyvinyl alcohol composite hydrogels were synthesized as endoscopic tattooing inks. Alginate (Alg) conjugated with phenylboronic acid (PBA) groups in the backbone was crosslinked with polyvinyl alcohol (PVA) because of the dynamic bonds between the phenylboronic acid in alginate and the cis-diol groups of PVA. The carbon black-incorporated Alg-PBA/PVA hydrogels exhibited self-healing and re-shapable properties, indicating that improved intraoperative localization could be achieved. In addition, the adhesive tattooing hydrogels were stably immobilized on the target regions in the intraperitoneal spaces. These carbon black-containing self-healing adhesive hydrogels are expected to be useful in various surgical procedures, including endoscopic tattooing.

Reduced graphene oxide reinforced PDA-Gly-PVA composite hydrogel as strain sensors for monitoring human motion

Hydrogels with soft, skin-friendly properties and high biocompatibility are promising alternatives to traditional sensors. However, balancing electrical conductivity and sensitivity remains a significant challenge. The sensitivity-improved strain sensor was designed by reduced graphene oxide (rGO) reinforced polydopamine (PDA)-glycerol (Gly)-polyvinyl alcohol composite hydrogels (PGPHs). The hydrogels exhibited excellent sensing sensitivity with a gauge factor of 2.78, conductivity of 2.2 S/m, tensile deformation of 200%, fast response time of 370 ms, and recovery time of 260 ms, surpassing those of most previously reported hydrogel-based strain sensors. This improvement can be attributed to the high electrical conductivity and uniform distribution of the rGO associated with Gly and PDA. PGPHs also exhibited an attractive monitoring effect for hand movements and precise detection feedback for the slight dynamics of the pharynx. Hydrogel-based strain sensors have been demonstrated as a potentially sustainable solution for dynamic detection and communication.

Highly stretchable, adhesive, and biocompatible hydrogel platforms of tannic acid functionalized spherical nanocellulose for strain sensors

The development of multifunctional wearable electronic devices has received considerable attention because of their attractive applications. However, integrating multifunctional abilities into one component remains a challenge. To address this, we have developed a tannic acid-functionalized spherical nanocellulose/polyvinyl alcohol composite hydrogel using borax as a crosslinking agent for strain-sensing applications. The hydrogel demonstrates improved mechanical and recovery strengths and maintains its mechanical strength under freezing conditions. The hydrogels show ultra-stretching, adhesive, self-healing, and conductive properties, making them ideal candidates for developing strain-based wearable devices. The hydrogel exhibits good sensitivity with a 4.75 gauge factor. The cytotoxicity of the developed hydrogels was monitored with human dermal fibroblast cells by WST-8 assay in vitro. The antibacterial potential of the hydrogels was evaluated using Escherichia coli. The hydrogels demonstrate enhanced antibacterial ability than the control. Therefore, the developed multifunctional hydrogels with desirable properties are promising platforms for strain sensor devices.

Three-dimensional boron nitride network/polyvinyl alcohol composite hydrogel with solid-liquid interpenetrating heat conduction network for thermal management

• Solid-liquid interpenetrating heat conduction network. • Heat conduction and storage function. • Efficient thermal management materials. Polyvinyl alcohol hydrogels have been used in wearable devices due to their good flexibility and biocompatibility. However, due to the low thermal conductivity ( κ ) of pure hydrogel, its further application in high power devices is limited. To solve this problem, melamine sponge (MS) was used as the skeleton to wrap boron nitride nanosheets (BNNS) through repeated layering assembly, successfully preparing a three-dimensional (3D) boron nitride network (BNNS@MS), and PVA hydrogels were formed in the pores of the network. Due to the existence of the continuous phonon conduction network, the BNNS@MS/PVA exhibited an improved κ . When the content of BNNS is about 6 wt.%, κ of the hydrogel was increased to 1.12 W m −1 K −1 , about two times higher than that of pure hydrogel. The solid heat conduction network and liquid convection network cooperate to achieve good thermal management ability. Combined with its high specific heat capacity, the composites have an important application prospect in the field of wearable flexible electronic thermal management.

Strain-sensitive alginate/polyvinyl alcohol composite hydrogels with Janus hierarchy and conductivity mediated by tannic acid

To construct conductive hydrogels with a conductive and a non- or weakly conductive layer for comfortable and safe electronic application, marine biobased anionic polysaccharide sodium alginate (SA) and neutral polyvinyl alcohol (PVA) were employed as the hydrogel matrixes. Tannic acid (TA) was exploited to mediate the demixing of the miscible aqueous solution of SA and PVA in view of the much larger interaction strength of TA with PVA than both of TA with SA and PVA with SA calculated from the density functional theory (−40.21, −29.77 and −21.00 kcal·mol−1 respectively). The finally-fabricated alginate/PVA composite hydrogels not only possess a “Janus” hierarchy but manifest asymmetrical conductivity, i.e., one layer strongly conductive and another weakly conductive. The strongly conductive layer achieves a conductivity of more than 2.95 S·m−1, facilitating their application in soft electronic areas like human-machine interfaces, smart wearable devices and soft robots. The weakly conductive layer with the conductivity less than 0.60 S·m−1 and the thickness adjustable, constitutes a protective screen for another layer. The Janus hydrogels exhibit good mechanical performance, excellent strain-sensing performance and fatigue-resistant mechanics, conductivity and sensitivity.

Preparation of nanocellulose-polyvinyl alcohol composite hydrogels from Desmodium intortum (Mill.) Urb.: Chemical property characterization

Nanocrystalline cellulose (NCC) was extracted from Desmodium intortum (Mill.) Urb. by sulfuric acid hydrolysis, and the NCC and polyvinyl alcohol (PVA) were fused together by repeated freezing and thawing cycles to obtain nanofiber-polyethylene. The alcohol composite hydrogel was characterized by XRD, FTIR, and SEM methods. The results showed that nanocellulose is primarily blended with polyvinyl alcohol through physical cross-linking, and the water retention of the composite hydrogel is obvious. Specifically, when the amount of NCC added was 0.4%, the water content increased to 94.26%. In short, the nanocellulose extracted from Desmodium intortum (Mill.) Urb. can effectively improve the water retention and thermal stability of PVA, which provides an effective theoretical basis for the hydrogel in medical dressings and improves the application value of Desmodium intortum (Mill.) Urb.

Cellulosic/Polyvinyl Alcohol Composite Hydrogel: Synthesis, Characterization and Applications in Tissue Engineering.

The biomedical field still requires composite materials for medical devices and tissue engineering model design. As part of the pursuit of non-animal and non-proteic scaffolds, we propose here a cellulose-based material. In this study, 9%, 18% and 36% dialdehyde-functionalized microcrystalline celluloses (DAC) were synthesized by sodium periodate oxidation. The latter was subsequently coupled to PVA at ratios 1:2, 1:1 and 2:1 by dissolving in N-methyl pyrrolidone and lithium chloride. Moulding and successive rehydration in ethanol and water baths formed soft hydrogels. While oxidation effectiveness was confirmed by dialdehyde content determination for all DAC, we observed increasing hydrolysis associated with particle fragmentation. Imaging, FTIR and XDR analysis highlighted an intertwined DAC/PVA network mainly supported by electrostatic interactions, hemiacetal and acetal linkage. To meet tissue engineering requirements, an interconnected porosity was optimized using 0–50 µm salts. While the role of DAC in strengthening the hydrogel was identified, the oxidation ratio of DAC showed no distinct trend. DAC 9% material exhibited the highest indirect and direct cytocompatibility creating spheroid-like structures. DAC/PVA hydrogels showed physical stability and acceptability in vivo that led us to propose our DAC 9%/PVA based material for soft tissue graft application.

Double‐network polyvinyl alcohol composite hydrogel with self‐healing and low friction

AbstractPolyvinyl alcohol (PVA) hydrogel is considered the most promising candidate for artificial cartilage because of its good lubricity and low permeability. However, the efficacy of single‐network PVA hydrogels under variable loads has not yet been determined. In this study, a one‐step physical‐cross‐linking method was used to compose PVA/PEG double‐network composite hydrogels. We changed the polyethylene glycol (PEG) content of the composite gel and tested the frictional‐wear performance under different loads and speeds. With the mass fraction of PEG at 30 wt.%, the hardness of the PVA/PEG composite gel increased to 167.7% that of pure PVA. Under dry‐friction conditions, the average coefficient of friction was approximately 0.14 and the wear rate on the surface of the hydrogel was insignificant. The cross‐linking between PVA and PEG greatly enhanced the stability of the composite hydrogel polymer network. The structure of the composite gel was analyzed by a variety of standard methods. The hydrogel has excellent biocompatibility and self‐healing ability and is a self‐lubricating, self‐healing candidate material for articular‐cartilage repair.

Ultra-strong hydroxypropyl cellulose/polyvinyl alcohol composite hydrogel by combination of triple-network and mechanical training

To develop the hydrogels with high mechanical strength and excellent conductivity is always a challenging topic. In this study, the ultra-strong hydroxypropyl cellulose (HPC)/polyvinyl alcohol (PVA) composite hydrogels were prepared by combination of the triple-network and mechanical training. The proposed composite hydrogels were achieved by physically crosslinking HPC with PVA to form the first crosslinking network, in which the HPC fibers could decrease the crosslinking density of PVA matrix and generate a lot of water-rich porous area. Then, 2-hydroxyethyl acrylate (HEA), acrylamide (AM) and aluminium chloride diffused into the first network to fabricate the chemical crosslinking network and ionically cross-linked domains. The formation of triple-network enhanced the mechanical strength and toughness to 1.87 MPa and 339.09 kJ/m3, respectively. Especially, the crystalline domains of PVA chains could improve the hydrogel's fatigue resistance, and the orderly arrangement of the crystalline domains achieved through mechanical training process could further enhance the mechanical strength. The mechanical strength of pre-stretched composite hydrogel was increased up to 2.8 MPa. The composite hydrogels exhibit great applications in sensors, human–machine interactions, and wearable devices.