Carboxymethyl Cellulose Hydrogel Research Articles

Super-tough and self-healable all-cellulose-based electrolyte for fast degradable quasi-solid-state supercapacitor

Recyclable and degradable supercapacitors have promising applications for a sustainable energy storage industry. Herein, we prepare a dual-physical crosslinking (DP) carboxymethyl cellulose (CMC) hydrogel with high-toughness, healability, and electric conductivity by integrating abundant ions into the matrix. The prepared hydrogel displays a maximum compressive fracture stress of 4.42 MPa, fast healing in five seconds, and full degradation within eight days. Moreover, the fabricated supercapacitor shows high specific capacitance (309 F g−1) and volumetric capacitance (2.60 F cm−3). The supercapacitor achieves a healing efficiency of 93.9 % after five cuttings, and exhibits a cycling stability of 84.6 % capacitance retention after 1000 cycles. These merits ensure that the all-cellulose-based supercapacitor can operate in case of sudden collision and deformation, which contribute to reducing the environmental hazards from supercapacitor's preparation to its abandonment.

Adsorption removal of Brilliant green and Safranin‐O contaminants from water using a hydrogel based on carboxymethyl cellulose and sodium alginate crosslinked by epichlorohydrin

AbstractThe current study investigates the adsorption properties of a chemically crosslinked hydrogel based on sodium alginate (NaALG) and carboxymethyl cellulose (CMC). The structural characteristics of the investigated hydrogel are described using information from Fourier Transform–infrared spectra, X‐ray diffraction patterns and field emission scanning electron microscopy pictures. The NaALG/epichlorohydrin (ECH)/CMC hydrogel was synthesised under optimised conditions with respect to the swelling percentage. Various reaction parameters were varied to obtain the maximum swelling percentage. The synthesised hydrogel was taken as an adsorbent in the decolorisation of Brilliant green (BG) and Safranin‐O (SO) dyes from water. According to the kinetic investigations, the decolorisation equilibrium of SO by NaALG/ECH/CMC was discovered in 4 hours (98.98%), while the removal of BG by NaALG/ECH/CMC took 6 hours (97.7%). Chemical processes were used to describe the decolorisation mechanisms, which significantly supported the pseudo‐first‐order model. NaALG/ECH/CMC hydrogel absorption was indicated to take place in monolayer adsorption form (Langmuir isotherm). The highest adsorption capacity for BG was discovered to be 864.8 mg g−1 and for SO it was 193.1 mg g−1, by synthesised hydrogel, where “mg” refers to the commercial colourant and not to the pure dye. Therefore, the synthesised hydrogel can be considered as a smart device for the adsorption of dye in water purification tasks.

Evaluation of Chokeberry/Carboxymethylcellulose Hydrogels with the Addition of Disaccharides: DART-TOF/MS and HPLC-DAD Analysis

With the growing awareness of the importance of a healthy diet, the need for the development of novel formulations is also on the rise. Chokeberry products are popular among consumers since they are a rich source of polyphenols that are responsible for antioxidant activity and other positive effects on human health. However, other natural food ingredients, such as disaccharides, can affect their stability. The aim of this study was to investigate the influence of disaccharides addition on the polyphenol composition of chokeberry hydrogels. Hydrogels were prepared from chokeberry juice and 2% of carboxymethylcellulose (CMC) with the addition of 30%, 40%, or 50% of disaccharides (sucrose or trehalose). Samples were analyzed using DART-TOF/MS. The method was optimized, and the fingerprints of the mass spectra have been statistically processed using PCA analysis. Prepared samples were evaluated for total polyphenols, monomeric anthocyanins, and antioxidant activity (FRAP, CUPRAC, DPPH, ABTS assays) using spectrophotometric methods. Individual polyphenols were evaluated using HPLC-DAD analysis. Results showed the addition of disaccharides to 2% CMC hydrogels caused a decrease of total polyphenols. These findings confirm proper formulation is important to achieve appropriate retention of polyphenols.

High-performance homogeneous carboxymethylcellulose-stabilized Au@Ag NRs-CMC surface-enhanced Raman scattering chip for thiram detection in fruits

Cellulose material holds considerable promise for effective surface-enhanced Raman scattering (SERS) substrate construction due to its extensive availability, chemically modifying capacity, ease of manufacture, high flexibility and low optical activity. A large-area, high-sensitivity, stable and uniform Au@Ag nanorods (NRs)-CMC substrate was successfully developed via electrostatic repulsion by using negatively-charged core–shell Au@Ag NRs as SERS active plasmonic nanomaterial, combined with negatively-charged carboxymethylcellulose (CMC) hydrogel for nanoparticles stabilization, homodisperse and protection. The obtained Au@Ag NRs-CMC substrate showed excellent sensitivity for the detection of thiram residues in fruits containing low and abundant pigment interferents, such as apples and blueberries, with detection limits of 58 and 78 ppb, respectively. Additionally, it retained more than 80% SERS performance after storage for 9 months under ambient conditions, demonstrating its great potential in facilitating the commercialization of cellulose-based SERS technology for cost-effective detection of food contaminants with advantages of facile preparation procedure, uniformity, reproducibility and long-term stability.

Ultrasensitive Piezoresistive and Piezocapacitive Cellulose-Based Ionic Hydrogels for Wearable Multifunctional Sensing

Tactile sensors, namely, flexible devices that sense physical stimuli, have received much attention in the last few decades due to their applicability in a wide range of fields like the world of wearables, soft robotics, prosthetics, and e-skin. Nevertheless, achieving a trade-off among stretchability, good sensitivity, easy manufacturability, and multisensing ability is still a challenge. Herein, an extremely flexible strain sensor composed of a cellulose-based hydrogel is presented. A natural biocompatible carboxymethylcellulose (CMC) hydrogel endowed with ionic conductivity by sodium chloride (NaCl) was used as the sensitive part. Both the sensible layer and electrodes were investigated with an innovative approach for wearable sensor applications based on electrochemical impedance spectroscopy to find the best device configuration. The sensor, exploitable both as a piezoresistor and as a piezocapacitor, presents high sensitivity to external stimuli, together with an extreme stretchability of up to 600%, showing the best strain and temperature sensitivity among the ionic conductive hydrogel-based devices presented in the literature. The very high strain sensitivity enables the hydrogel to be implemented in wearable strain sensors to monitor different human motions and physiological signals, representing a valid solution for the realization of transparent, easily manufacturable, and low-environmental-impact devices.

A low-modulus, adhesive, and highly transparent hydrogel for multi-use flexible wearable sensors

Flexible materials have been widely applied in wearable sensors, but their high modulus and non-adhesion impede their widespread applications. In this work, a polyacrylic acid (PAA)-enhanced carboxymethyl cellulose (CMC) hydrogel (PEC hydrogel) was prepared via a two-step method to be utilized in flexible wearable sensors. The hydrogel presented a transparency of over 90 % (400–800 nm). Because of polymer chain entanglements and non-covalent interactions between PAA and CMC, the tensile properties of the hydrogel were enhanced, affording the PEC hydrogel with high stretchability (492 %) and low tensile strength (< 12.5 kPa). A hydrogel-based resistive strain sensor exhibited a wide sensing range (0–300 %, GF = 3.16), fast response time (125 ms), and excellent durability (over 1500 cycles from 0 % to 100 % strain). Owing to the introduction of polar groups, the hydrogel could be adhered to various substrates, and the peeling strength on pig skin (a replacement for human skin) was 53.97 N/m. Thanks to its low modulus, adhesion, and sensing performance, the hydrogel was assembled into a wearable strain sensor that accurately detected multiple human body movements. The hydrogel was also applied in a capacitive pressure sensor, which possessed a fast response time (100 ms) and high sensitivity. This work provides facile method for fabricating hydrogels used in Multi-use Flexible Wearable Sensors.

Immediately activating hemostatic cellulose sealants for uncontrolled hemorrhage

The control of bleeding is one of the most important processes in surgical treatments and wound healing, and the development of effective hemostatic agents is urgently required. An ideal hemostatic agent should be immediately activated when exposed to bleeding to reduce blood loss as soon as possible and should be user-friendly for urgent situations. To meet these demands, we functionalized carboxymethyl cellulose (CMC) with two different phenolic moieties, catechol (CA) and pyrogallol (PG), and then formulated each CMC derivative into adhesive hydrogels with high hemostatic ability. These hemostatic platforms exhibited sturdy modulus (CMC-CA: 0.55 ± 0.08 kPa, CMC-PG: 1.37 ± 0.24 kPa), wet-tissue adhesiveness (CMC-CA: 2.19 ± 0.53 kPa, CMC-PG: 3.13 ± 0.25 kPa), and rapid crosslinking within seconds for wound closure. We transformed the CMC hydrogels into a patch design, resulting in 16∼19-fold increase in elastic modulus and 3∼4-fold increase in adhesiveness, which can completely seal the wound for more efficient hemostatic action. The adhesive CMC patches exhibited superior hemostatic capability to fibrin glue as a wound sealant by rapidly stopping bleeding in mouse liver hemorrhage. This study demonstrated that bio-inspired polyphenolic CMC hydrogels produce a highly effective, instantly working hemostatic agent.

DNA-Tetrahedra Corona-Modified Hydrogel Microcapsules: "Smart" ATP- or microRNA-Responsive Drug Carriers.

The assembly of adenosine triphosphate (ATP)-responsive and miRNA-responsive DNA tetrahedra-functionalized carboxymethyl cellulose hydrogel microcapsules is presented. The microcapsules are loaded with the doxorubicin-dextran drug or with CdSe/ZnS quantum dots as a drug model. Selective unlocking of the respective microcapsules and the release of the loads in the presence of ATP or miRNA-141 are demonstrated. Functionalization of the hydrogel microcapsules a with corona of DNA tetrahedra nanostructures yields microcarriers that revealed superior permeation into cells. This is demonstrated by the effective permeation of the DNA tetrahedra-functionalized microcapsules into MDA-MB-231 breast cancer cells, as compared to epithelial MCF-10A nonmalignant breast cells. The superior permeation of the tetrahedra-functionalized microcapsules into MDA-MB-231 breast cancer cells, as compared to analog control hydrogel microcapsules modified with a corona of nucleic acid duplexes. The effective permeation of the stimuli-responsive, drug-loaded, DNA tetrahedra-modified microcapsules yields drug carriers of superior and selective cytotoxicity toward cancer cells.

Physicochemical Properties of Cellulose-Based Hydrogel for Biomedical Applications.

Hydrogels are three-dimensional network structures of hydrophilic polymers, which have the capacity to take up an enormous amount of fluid/water. Carboxymethyl cellulose (CMC) is a commercially available cellulose derivative that can be used for biomedical applications due to its biocompatibility. It has been used as a major component to fabricate hydrogels because of its superabsorbent nature. In this study, we developed carboxylic acid crosslinked carboxymethyl cellulose hydrogels for biomedical applications. The physicochemical, morphological, and thermal properties were analyzed to confirm the crosslinking of carboxymethyl cellulose. Fourier-transform infrared spectra confirmed the crosslinking of carboxymethyl cellulose with the presence of peaks due to an esterification reaction. The distinct peak at 1718 cm-1 in hydrogel samples is due to the carbonyl group vibrations of the ester bond from the crosslinking reaction. The total carboxyl content of the sample was measured with crosslinker immersion time. The swelling of crosslinked hydrogels showed an excellent swelling capacity for CG02 that is much higher than CG01 in water and PBS. Morphological analysis of the hydrogel showed it has a rough surface. The thermal degradation of hydrogel showed stability with respect to temperature. However, the mechanical analysis showed that CG01 has a higher compressive strength than CG01. The optimum swelling ratio and higher compressive strength of CG01 hydrogels could give them the ability to be used in load-bearing tissue regeneration. These results inferred that the carboxylic acid crosslinked CMC hydrogels could be a suitable matrix for biomedical or tissue-engineering applications with improved stability.

Polymers blended peanuts activated carbon composite hydrogels fabricated Ag NPs as dip-catalyst for industrial dyes discoloration in aqueous medium

Hydrogels are three-dimensional superabsorbent polymers with many biomedical, medicinal, and environmental applications. Single and double-networks carboxymethyl cellulose (CMC) and polyacrylamide (PAA) composites hydrogels were synthesized through freeze-thawing process, using formaldehyde. The CMC or PAA single and double networks were prepared by blending them separately with activated carbon (AC), and was designated as CMC-AC, PAA-AC, and PAA-CMC-AC. The Ag ions adsorbed by these hydrogels were chemically reduced with NaBH 4 to zero-valent Ag nanoparticles (Ag NPs). The Ag NPs supported hydrogels were used as a dip-catalyst for the discoloration of dyes in the presence of NaBH 4 . It was observed that the experimental data is well-fitted in the zeroth order kinetics. For instance, the PAA-AC@Ag NPs indicated the highest rate constant of 2.9 × 10 −1 and 4.2 × 10 −1 min −1 Congo red (CR) and methyl orange (MO) dyes discoloration. The other hydrogels supported Ag NPs also exhibited strong catalyst activity, but PAA@Ag displayed the highest catalyst activity among the series. The FESEM images of the Ag NPs supported hydrogels suggesting some range of self-assemblies, and EDS gives elemental purity. FTIR and Raman spectroscopy indicated various functional groups of the catalysts. Similarly, the crystallite size and %crystallinity was calculated from XRD . • Synthesis of single and double networking hydrogels. • Synthesis of single and double networking hydrogels with and without activated carbon. • Anchoring of Ag nanoparticles. • Discoloration of industrial dyes.

In-situ forming hydrogel based on thiolated chitosan/carboxymethyl cellulose (CMC) containing borate bioactive glass for wound healing

Suitable wound dressings for accelerating wound healing are actively being designed and synthesised. In this study, thiolated chitosan (tCh)/oxidized carboxymethyl cellulose (OCMC) hydrogel containing Cu-doped borate bioglass (BG) was developed as a wound dressing to improve wound healing in a full-thickness skin defect of mouse animal model. Thiolation was used to incorporate thiol groups into chitosan (Ch) to enhance its water solubility and mucoadhesion characteristics. Here, the in situ forming hydrogel was successfully developed using the Schiff-based reaction, and its physio-chemical and antibacterial characteristics were examined. Borate BG was also incorporated in the generated hydrogel to promote angiogenesis and tissue regeneration at the wound site. Investigations of in vitro cytotoxicity assays demonstrated that the synthesised hydrogels showed good biocompatibility and promoted cell growth. These results inspired us to investigate the effectiveness of skin wound healing in a mouse model. On the backs of animals, two full-thickness wounds were created and treated utilising two different treatment conditions: (1) OCMC/tCh hydrogel, (2) OCMC/tCh/borate BG, and (3) control defect. The wound closure ratio, collagen deposition, and angiogenesis activity were measured after 14 days to determine the healing efficacy of the in situ hydrogels used as wound dressings. Overall, the hydrogel containing borate BG was maintained in the defect site, healing efficiency was replicable, and wound healing was apparent. In conclusion, we found consistent angiogenesis, remodelling, and accelerated wound healing, which we propose may have beneficial effects on the repair of skin defects.

Synthesis of cross-linked carboxymethyl cellulose and poly (2-acrylamido-2-methylpropane sulfonic acid) hydrogel for sustained drug release optimized by Box-Behnken Design

This research aims to fabricate and characterize chemically crosslinked CMC/PVP-co-poly (AMPS) based hydrogel for the sustained release of model drug metoprolol tartrate through the free radical polymerization technique. Box-Behnken Design was used to optimize CMC/PVP-co-poly (AMPS) hydrogel by varying the content of reactants such as; polymers (CMC and PVP), monomer (AMPS), and crosslinker (EGDMA). Carboxymethyl cellulose (CMC) was crosslinked chemically with AMPS with a constant ratio of PVP by the ethylene glycol dimethacrylate as the crosslinker in the presence of sodium hydrogen sulfite (SHS)/ammonium peroxodisulfate (APS) as initiators. After developing CMC-based hydrogels using different polymers, monomer, and crosslinker concentrations, this study encompassed dynamic swelling, sol–gel fraction, drug release and chemical characterizations such as FTIR, XRD, TGA, DSC, and SEM. In vitro drug release and swelling were performed at 1.2 and 6.8 pH to determine the sustained release pattern and pH-responsive behavior. These parameters depended on the crosslinker, polymer, and monomer ratios used in the formulation development. XRD, SEM, and FTIR showed the successful grafting of constituents resulting in the formation of a stable hydrogel. DSC and TGA confirmed the thermodynamic stability of the hydrogel. Hydrogel swelling was increased with an increase in the ratio of monomer; however, an increase in the ratio of polymer and crosslinker decreased the hydrogel swelling. In vitro gel fraction and drug release also depended on polymer, monomer, and crosslinker ratios. The fabricated CMC/PVP-co-poly (AMPS) hydrogels constituted a potential system for sustained drug delivery.

3D printing of hydrogel-based seed planter for in-space seed nursery

With the improved reliability and accessibility of 3D printing technology, interest in manufacturing parts using 3D printing became popular across academic and industrial sectors. Compared with traditional manufacturing approaches, it requires less facility and maintenance and provides the possibility of fast customization and modification at a lower cost. With the necessity of self-sustentation, growing plant in space is one of the most popular topics. Carboxymethyl cellulose hydrogel (CMC-gel) is one of the best candidates for sprouting substrate with 3D printing fabrication as it is non-toxic, biodegradable, and suitable for extrusion-based 3D printing. In this study, CMC-gel was designed and printed into different dimensions as soybean sprouting substrate. Soybeans were placed into the printed gel with different orientations. Upon 120 hours of sprouting without visible light, soybeans with hilum facing side had the highest water absorption average comparing those facing up or down. Across different hydrogels, hydrogel weight dominated the water absorption efficiency. These findings signified that bean orientation affects the sprouting process, and hydrogel weight can be further reduced upon 120 hours of the sprouting timespan. This study demonstrates the substrate geometry and seed orientation impacts on germination of soybeans, proposed guidelines for optimizing the sprouting process for high-level edible plants, and promoting innovated in-space seed nursery approach.

Synthesis and Applications of Carboxymethyl Cellulose Hydrogels.

Hydrogels are basic materials widely used in various fields, especially in biological engineering and medical imaging. Hydrogels consist of a hydrophilic three-dimensional polymer network that rapidly expands in water and can hold a large volume of water in its swelling state without dissolving. These characteristics have rendered hydrogels the material of choice in drug delivery applications. In particular, carboxymethyl cellulose (CMC) hydrogels have attracted considerable research attention for the development of safe drug delivery carriers because of their non-toxicity, good biodegradability, good biocompatibility and low immunogenicity. Aiming to inspire future research in this field, this review focuses on the current preparation methods and applications of CMC gels and highlights future lines of research for the further development of diverse applications.

PH-responsive hydrogels of carboxymethyl cellulose and polyethyleneimine for efficient removal of ionic dye molecules

A carboxymethyl cellulose (CMC)/polyethyleneimine (PEI) hybrid hydrogel was successfully prepared under green processing conditions. The CMC and PEI formed a polyelectrolyte complex, and the three-dimensional (3D) network structure was hardened by chemical crosslinking, resulting in suitable hydrogel properties. In the prepared CMC/PEI polyelectrolyte hydrogel, the surface charge was easily switched according to the pH change, and the resulting swelling and contraction was reversible. The pH sensitivity of the CMC/PEI hydrogel was effective in removing ionic dye contaminants, and as a result, it showed an excellent removal capacity of 319 mg/g for anionic acid orange (AO) and 129 mg/g for cationic methylene blue (MB). In addition, the CMC/PEI polyelectrolyte hydrogel maintained structural stability despite repeated changes in surface charge characteristics and shrinkage-swelling due to repeated pH conversion. As a result, in the reuse process through repeated adsorption and desorption, it showed an excellent reuse efficiency of more than 93% even after 10 reuse cycles.

Food-Grade Bigels with Potential to Replace Saturated and Trans Fats in Cookies.

Fats play multiple roles in determining the desirable characteristics of foods. However, there are health concerns about saturated and trans fats. Bigels have been proposed as a novel fat replacer in foods. This research evaluated the role of the type of hydrogel in the development of bigels to be used as fat replacers in cookies. Bigels were made with beeswax/canola oil oleogel and sodium alginate and carboxymethylcellulose hydrogels. The results showed that the peroxide value and binding capacity of bigels were affected by the type of hydrogel used. However, their fatty acid profile, p-anisidine value, oxidative stability, and texture remained unchanged. Using bigels as fat replacers, cookies were obtained with a hardness similar to those with original shortening, showing the potential of bigels for use in foods.

Redispersible 3D printed nanomedicines: An original application of the semisolid extrusion technique

Semisolid extrusion is a layer-by-layer 3D printing technique that produces objects from gels or pastes. This process can be carried out at room temperature, without using a light source, and has been explored in pharmaceutics in the last few years. In this regard, our group hypothesized its suitability for the production of three-dimensional (3D) printed nanomedicines containing drug-loaded organic nanocarriers. In this study, the original application of the semisolid extrusion was evaluated to produce redispersible 3D printed oral solid forms containing drug-loaded polymeric nanocapsules. A carboxymethyl cellulose hydrogel containing resveratrol and curcumin co-encapsulated in nanocapsules was prepared, and the nanocapsules did not change its complex viscosity and yield stress. Homogeneous and yellow cylindrical-shaped solid forms were printed, with a mean weight of 0.102 ± 0.015 g, a polyphenol content of approximately 160 μg/unit, disintegration time of <45 min, and recovery of the nanosized carriers. The polyphenols were completely released from the solid forms after 8 h, although part of them remained encapsulated in the nanocapsules. This study represents a proof of concept concerning the use of semisolid extrusion to produce 3D printed forms composed of polymeric nanocapsules in a one-step process. It proposes an original platform for the development of solid nanomedicines from liquid aqueous nanocapsule suspensions.

SYNTHESIS OF CELLULOSE-BASED SUPERABSORBENT HYDROGEL FILLED WITH CELLULOSE NANOFIBER FROM OIL PALM EMPTY FRUIT BUNCHES

Oil palm empty fruit bunches (OPEFB) are waste products from the oil palm plantations, which is still an issue in Indonesian plantations. The high cellulose content in OPEFB enables them to be processed into cellulose nanofibers (CNF) that can be applied as fillers in the hydrogel. This research aimed to synthesize cellulose-based superabsorbent hydrogel and observe the optimal condition to produce hydrogel with high absorption and good thermal properties. CNF-based hydrogel is an excellent option to improve the physicochemical characteristics of the hydrogel. In this work, carboxy methyl cellulose hydrogel was firstly prepared by using citric acid. Then, CNF were added as fillers at different ratio variations, such as 0, 1, 3, 5, and 7 wt%. The surface morphology of the hydrogel showed rough surfaces, except for the 7 wt% CNF variation that produced hydrogel with a homogeneous surface. The cross-linking between the hydrogel and the fillers was evaluated by Fourier-Transform Infrared Spectroscopy (FTIR). A peak associated with the carboxylic acid functional group indicated hydrogel formation. The incorporation of CNF did not change the FTIR spectra since both materials had similar structures. Water absorption analysis showed that the developed product could be classified as a superabsorbent since all samples showed a degree of swelling above 200 g.g−1. CNF content at a 1 %wt ratio had the highest water retention and best thermal stability. The hydrogel showed exceptional characteristics, being suitable for various applications, mainly in agricultural sectors that required water delivery to the soil.

A novel modified carboxymethyl cellulose hydrogel adsorbent for efficient removal of poisonous metals from wastewater: Performance and mechanism

A cost-efficient and simple method, grafting sodium sulfonate groups (−SO3Na) onto carboxymethyl cellulose (CMC), was developed to form hydrogel adsorbents for the removal of poisonous metals including Cu(Ⅱ) and Zn(Ⅱ) from wastewater. In this work, cellulose-based hydrogels (CMC-g-P(AA-co-SS)) were prepared using acrylic acid (AA) and sodium styrene sulfonate (SS). FTIR, XPS, SEM, and EDX were employed to analyze the surface morphology and structure of CMC-g-P(AA-co-SS). The results revealed that the synergistic effect of −SO3Na and carboxylate groups (−COO−) facilitated the adsorption of heavy metals. Moreover, introducing AA and SS enhanced the swelling degree of CMC hydrogels. The results of adsorption experiments showed that high adsorption efficiencies were obtained for Cu(Ⅱ) and Zn(Ⅱ) (200.44 mg/g and 192.28 mg/g, respectively) within 180 min. The adsorption isotherm and kinetics indicated that the monolayer chemical adsorption dominated the process. After 5 cycles, the adsorption activity of CMC-g-P(AA-co-SS) remained high, with the adsorption capacity for Cu(Ⅱ) and Zn(Ⅱ) being 93.3% and 78.3% of the original, respectively. Thus, the CMC-g-P(AA-co-SS) is a promising adsorbent candidate for the removal of poisonous metals from wastewater.

Outstanding temperature‐tolerant conductive polyacrylamide/sodium carboxymethylcellulose hydrogel with ultra‐stretchability and good strain sensing performance

AbstractFlexible sensors based on conductive hydrogels have shown surprising potential in the field of electronic skin and human–computer interaction. However, pure water in the hydrogel will inevitably freeze at low temperature or evaporate quickly in dry environment, resulting in the failure of hydrogel as a flexible sensor. Here, inorganic ions (Li+ and Cl−) and glycerol were introduced into the polyacrylamide/sodium carboxymethylcellulose (PAM/CMCNa) composite hydrogel networks through the strategy of solvent replacement. The optimized hydrogel had a quite large elongation at break of 2000%, and a breaking strength of more than 0.14 MPa. The synergistic effect of inorganic ions and glycerol enabled the hydrogel to maintain a good flexibility in a wide temperature range of −20–45°C, which could meet the work needs of the hydrogel in high temperature or extremely cold environments. The hydrogel showed a very wide working range of 1000%, a fast response time of 150 ms, and a high stability and repeatability of 500 cycles during strain sensing detection. Besides, the hydrogel could capture the large and subtle body movements accurately and stably. Therefore, this hydrogel may be applied as in wearable sensing devices used in extreme environments.