Interpenetrating Network Hydrogels Research Articles

Synthesis and characterization of interpenetrating network hydrogels based on sugar beet pectin and heteroprotein complex: Structural characteristics and physicochemical properties

Synthesis and characterization of interpenetrating network hydrogels based on sugar beet pectin and heteroprotein complex: Structural characteristics and physicochemical properties

Dynamic Water Microskin Induced by Photothermally Responsive Interpenetrating Hydrogel Networks for High‐Performance Light‐Tracking Water Evaporation

AbstractSolar‐driven interfacial water evaporation is attracting increasing attention as a promising environmentally‐friendly solution to freshwater scarcity. It has been proven that a thin water layer on photothermal materials can prevent solar energy from invalidly heating the excess water to enhance the evaporation rate. However, the current water layers are usually formed on inelastic materials via confined capillarity, which are static and uncontrollable. Herein, we propose a flexible hydrogel‐based photothermal conversion material with thermal responsiveness by facile frontal polymerization, which can generate a unique dynamic water microskin (DWMS) during the solar evaporation process. The copolymerized hydrogel, introduced by the second polymeric poly(vinyl alcohol) network and thermally responsive poly(N‐isopropylacrylamide) (PNIPAM), exhibits reinforced mechanical strength and photothermally triggers reversible shrinking/swelling cycles that enable a thin water layer (≈32 µm) to balance the feedwater supply and photothermic energy input dynamically. As a result, a stable superior vaporization rate of 8.7 kg m−2 h−1 is achieved based on a cylindrical hydrogel with 6 cm height under 1 sun. Moreover, the simultaneous responsive bending allows efficient omnidirectional solar evaporation by light‐tracking to ensure maximum perpendicular solar absorption, which provides an alternative strategy for durable high‐efficiency solar evaporators for effective thermal management and solar utilization.

Photothermal-Induced Multimodal Antibacterial Dressing Comprising N-Halamine Hydrogel Loaded with Cow Dung Biochar for Infected Wound Healing.

Disposal of the cow dung pollutants arising from cattle farming threatens the environment and public safety in diverse ways. To date, researchers have worked on developing new pathways to control and manage cattle farming wastes, but most do not involve the reuse of these wastes. Herein, a cow dung biochar-modulated photothermal N-halamine hydrogel (i.e., PAN/CA/CoBC/pMAG-Cl) was designed for converting cow dung into biochar (CoBC), which was then coupled with a 3D interpenetrating hydrogel network to treat infected wounds. The PAN/CA/CoBC/pMAG-Cl hydrogel exhibited excellent synergistic antibacterial performance against 106 CFU·mL-1 Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 60 min. The bactericidal effect was multimodal, involving CoBC-based photothermal killing (i.e., temperature as high as 80.5 °C) after 808 nm near-infrared light irradiation for 10 min, contact killing through the strong oxidative characteristic of N-halamine (pMAG-Cl), and release killing via active halogens (i.e., Cl+) reinforced by the photothermal action of CoBC. The S. aureus-infected wound model in vivo demonstrated that the PAN/CA/CoBC/pMAG-Cl hydrogel worked as an ideal wound dressing, capable of resisting bacterial infection, accelerating the healing process, and promoting epithelial regeneration. This proposed strategy could indicate a new way for the disposal of cow dung pollutant and its reuse in antibacterial-associated applications.

Spectroscopic and Thermal Characterisation of Interpenetrating Hydrogel Networks (IHNs) Based on Polymethacrylates and Pluronics, and Their Physicochemical Stability under Aqueous Conditions

This study describes the physicochemical characterisation of interpenetrating hydrogel networks (IHNs) composed of either poly(hydroxyethylmethacrylate, p(HEMA)) or poly(methacrylic acid, p(MAA)), and Pluronic block copolymers (grades F127, P123 and L121). IHNs were prepared by mixing the acrylate monomer with Pluronic block copolymers followed by free radical polymerisation. p(HEMA)–Pluronic blends were immiscible, evident from a lack of interaction between the two components (Raman spectroscopy) and the presence of the glass transitions (differential scanning calorimetry, DSC) of the two components. Conversely, IHNs of p(MAA) and each Pluronic were miscible, displaying a single glass transition and secondary bonding between the carbonyl group of p(MAA) and the ether groups in the Pluronic block copolymers (Raman and ATR-FTIR spectroscopy). The effect of storage of the IHNs in Tris buffer on the physical state of each Pluronic and on the loss of Pluronic from the IHNs were studied using DSC and gravimetric analysis, respectively. Pluronic loss from the IHNs was dependent on the grade of Pluronic, time of immersion in Tris buffer, and the nature of the IHN (p(HEMA) or p(MAA)). At equilibrium, the loss was greater from p(HEMA) than from p(MAA) IHNs, whereas increasing ratio of poly(propylene oxide) to poly(ethylene oxide) decreased Pluronic loss. The retention of each Pluronic grade was shown to be primarily due to its micellization; however, hydrogen bonding between Pluronic and p(MAA) (but not p(HEMA)) IHNs contributed to their retention.

Microcrystalline cellulose and itaconic acid pH sensitive semi interpenetrating network hydrogel for oral insulin delivery

Diabetes mellitus is one of the important causes of death worldwide. Generally, a subcutaneous route is used for insulin administration, but has showed low patient compliance. Extensive research has been conducted to identify molecules capable of delivering insulin orally, for this hydrogel based on microcrystalline cellulose and itaconic acid have been produced and explored. Free radical polymerization as a technique was employed for manufacturing the hydrogels using potassium persulphate as initiator and N, N′-methylene bisacrylamide (NNMBA) as a crosslinker. These pH- sensitive exhibited a swelling capacity of up to 20.38 g/g in distilled water and also revealed stronger swelling in glucose solutions than saline solutions. The pH sensitivity of the hydrogels was confirmed by studying the swelling in different pH solutions. Alkaline solutions showed higher swelling than acidic solutions. SEM established the porous nature, and the structure was examined by FTIR analysis. Thermal degradation was examined using TGA. In vitro release study was done by Bradford assay at 595 nm. The result was further confirmed by in-vivo investigations on male Wistar adult rats and hence is an excellent vehicle for oral insulin administration.

Enhancing frost-resistant and electrically conductive properties of bacterial cellulose-based IPN hydrogel wound dressings via photopolymerization: Towards epidermal sensor applications

Conventional wound dressings are limited in their application due to the difficulty of maintaining normal use in cold conditions and a lack of functionality. In this study, photopolymerization was employed to fabricate a wound dressing with the capacity to monitor vital signs in cold environments. Utilizing bacterial cellulose (BC) to form an Interpenetrating Network (IPN) structure, the dressing exhibits enhanced water retention and mechanical properties, with a notable increase in mechanical strength to 540.37 KPa. Moreover, it maintains excellent mechanical resilience and electrical conductivity (9.01 × 10−3 S/cm) even at temperatures as low as −20 ℃. Incorporation of positively charged quaternary ammonium salts imparts potent antibacterial properties to the hydrogel against Staphylococcus aureus and Escherichia coli by electrostatically adsorbing to and disrupting negatively charged bacterial cell membranes, resulting in the leakage of internal fluids. The efficacy of the hydrogel in promoting wound healing was validated through rat-infected wound models. Hematoxylin and eosin (H&E) staining confirmed a reduction in inflammation at the wound site, improved wound healing, and a marked increase in the wound healing rate. Moreover, the hydrogel has remarkable electrical conductivity (1.25 × 10−2 S/cm), enabling the detection of subtle signals (e.g., strain 0.25 %) crucial for emergency wound management to prevent infections. Of significant importance, these hydrogels can function as electrodes for monitoring electrocardiogram (ECG) signals and respiratory status, facilitating timely assessment of vital signs in casualties. This innovative hydrogel wound dressing holds promise for simultaneously monitoring human vital signs and treating wounds in cold outdoor settings, thus offering broad applications in the realms of wound management and dressing for cold outdoor sports.

Facile fabrication of a thermal/pH responsive IPN hydrogel drug carrier based on cellulose and chitosan through simultaneous dual-click strategy

Herein, an interpenetrating network hydrogel (IPN-Gel) based on cellulose and chitosan was synthesized via simultaneous amino-anhydride and azide–alkyne click reaction in water in one pot. The samples were characterized by various analytical methods including FTIR, SEM, XRD, XPS, 1H NMR and so forth. The fabrication conditions were optimized by single factor experiments with water uptake (WU) and gel mass fraction (GMF) as two indexes. The WU and GMF of the IPN-Gel prepared under optimized conditions were 1192.37 % and 74.00 %, respectively. Its WU descended with the ascension in temperature, and first descended and then gradually ascended with the ascension in pH, confirming that the IPN-Gel had thermal/pH dual responsiveness. Using 5-Fu as a model drug, the release behavior of 5-Fu in IPN-Gel was explored. Its release behavior could be regulated by changing temperature and pH values, and it followed the Korsmeyer Peppas model. The viability of 4 T1 cells and HUVEC cells exceeded 80 % after 48 h of incubation at a high concentration of 200 μg/mL IPN-Gel, and hemolytic percentage was below the allowed limit of 5 %. The study provides a new strategy for the preparation of the IPN-Gel with biocompatibility, swelling reversibility and controllable drug release.

Natural bioink of interpenetrating network hydrogels mimicking extracellular polymeric substances for microbial immobilization in water pollution control

Artificial biomanufacturing has been developed as a promising biotechnology for water pollution control. Effective bioimmobilization techniques are limited in application because of low productivity and the difficulty in achieving both mechanical strength and biocompatibility. Bioprinting technology, using biomaterials as bioink to enable the rapid on-demand production of bioactive structures, opens a new path for bioimmobilization. In this study, mimicking extracellular polysaccharide and protein of aerobic granular sludge (AGS), sodium alginate (SA) and silk fibroin methacryloyl (SilMA) were developed as the dual-component bioink with a suitable viscosity for bioprinting hydrogel. Interpenetrating network (IPN) hydrogel beads were manufactured using 1.5% (w/v) SA combined with 20% (w/v) SilMA through physical and covalent crosslinking, which exhibited excellent structural stability and bioactivity. The addition of SilMA provided a solution to the poor mechanical stability of SA-Ca hydrogels limited by Ca2+-Na+ ionic exchange. The unique structure of SilMA contributed to the reduction of hydrogel swelling as well as the prevention of SA loss. IPN hydrogels showed a swelling rate of less than 20% compared to the high swelling rate of more than 60% for SA hydrogels. On the other hand, SA controlled the hardening induced by excessive self-assembly of SilMA and improved mass transport in SilMA hydrogels. Compared to IPN hydrogels, SilMA hydrogels experienced a 15% volumetric shrinkage and exhibited a low water content of 92%. Sonication pretreatment of the dual-component bioink not only increased the intermolecular chain entanglement to form IPN, but also led to β-sheet content in SiMA reaching 46%–48%, which resulted in the formation of stable IPN hydrogels dominated entirely by physical crosslinking. Satisfactory proliferation and viability were achieved for the encapsulated bacteria in IPN hydrogels (μmax 1.49–2.18 d−1). Further, the IPN biohydrogels could maintain structural stability as well as achieve pollutant removal for treating synthetic wastewater with high Na+ concentration of 300 mg/L. The novel SA/SilMA hydrogel bioprinting strategy established in this study offers a new direction for bioimmobilization in water pollution control and other environmental applications.

PH Sensitive Dual Cross‐Linked Anionic and Amphoteric Interpenetrating Network Hydrogels for Adsorptive Removal of Anionic and Cationic Dyes

AbstractThe contamination of water by organic dye compounds are worldwide environmental problem due to their highly toxic nature. To address this environmental issue, a simple technique with highly efficient dye removal was developed to prepare pH‐ sensitive dual‐crosslinked anionic and amphoteric interpenetrating network (IPN) hydrogels based on Na‐carboxymethyl cellulose (Na‐CMC) using jute stick‐based cellulose. Crosslinked Na‐CMC and crosslinked κ‐carrageenan (KC) were interlaced by H‐bonding in anionic IPN hydrogel (An‐gel), but crosslinked Na‐CMC and crosslinked Chitosan (CS) were interlaced by electrostatic interaction in amphoteric IPN hydrogel (Am‐gel). In various operating conditions (pH, temperature, etc.) An‐gel displayed a higher number of swelling ratios of about 2560% at pH 7.2 and Am‐gel of about 1874% at pH 5.5. Based on the point of zero charge, An‐gel achieved the maximum removal efficiency of 81.62 % for methylene blue (MB) at pH 7.2, whereas Am‐gel achieved 85.38% removal efficiency for eosin yellow (EY) at pH 5.5. The adsorption kinetics of IPN hydrogels followed a pseudo‐second order model and best fitted by Langmuir isotherm model. The removal efficiency of MB and EY decreased slightly with increasing temperature. The values of ΔH°, ΔG°, and ΔS° indicated an exothermic, spontaneous, and disordered adsorption process.

Facile preparation of interpenetrating network hydrogel adsorbent from starch- chitosan for effective removal of methylene blue in water

Hydrogels based on biopolymers have attracted considerable interest in the last decades. Herein, an interpenetrating network hydrogel (IPN-Gel) adsorbent from starch-chitosan was fabricated facilely in one-pot through tandem Schiff base reaction and photopolymerization. First, aldehyde starch (DAS) was synthesized by the reaction of soluble starch with sodium periodate. Afterward, acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), polyethylene glycol dimethacrylate (PEGDMA), photoinitiator, chitosan and DAS were dissolved in water to obtain a clear solution. Schiff base reaction between chitosan and DAS took place quickly to form the first network, and then photopolymerization of AM, AMPS, and PEGDMA occurred under ultraviolet radiation to form the second network. The preparation conditions of the as-prepared IPN-Gel were optimized with two indexes of gel mass fraction and swelling ratio. Its swelling behavior with pH and temperature change was explored. Finally, its adsorption performance was characterized with methylene blue (MB) as a model contaminant. The maximum adsorption capacity of IPN-Gel can reach 2039 mg·g−1 at pH =10. Its adsorption performance accords with Langmuir isothermal model and pseudo-second-order kinetic model and it was mainly controlled by chemisorption. This strategy is expected to found broad application prospects in the preparation of hydrogel adsorbents.

Triple-crosslinked double-network alginate/dextran/dendrimer hydrogel with tunable mechanical and adhesive properties: A potential candidate for sutureless keratoplasty

An ideal adhesive hydrogel must possess high adhesion to the native tissue, biocompatibility, eligible biodegradability, and good mechanical compliance with the substrate tissues. We constructed an interpenetrating double-network hydrogel containing polysaccharides (alginate and dextran) and nanosized spherical dendrimer by both physical and chemical crosslinking, thus endowing the hydrogel with a broad range of mechanical properties, adhesive properties, and biological functions. The double-network hydrogel has moderate pore sizes and swelling properties. The chelation of calcium ions significantly enhances the tensile and compressive properties. The incorporation of dendrimer improves both the mechanical and adhesive properties. This multicomponent interpenetrating network hydrogel has excellent biocompatibility, tunable mechanical and adhesive properties, and satisfied multi-functions to meet the complex requirements of wound healing and tissue engineering. The hydrogel exhibits promising corneal adhesion capabilities in vitro, potentially supplanting the need for sutures in corneal stromal surgery and mitigating the risks associated with donor corneal damage and graft rejection during corneal transplantation. This novel polysaccharide and dendrimer hydrogel also shows good results in sutureless keratoplasty, with high efficiency and reliability. Based on the clinical requirements for tissue bonding and wound closure, the hydrogel provides insight into solving the mechanical properties and adhesive strength of tissue adhesives.

3D skeletal muscle tissue culture in vitro by using hydrogel interpenetrating network

Abstract Muscle cells can not only be used for pathological research and drug detection, but also can be combined with soft robots to form biological hybrid robots. Mature muscle tissue had advantages such as good elasticity, self-repair, and multi-signal perception. Although there are many methods for 3D muscle tissue culture, muscle tissue is difficult to be used due to the insufficient material properties and long culture period. In this study, we exploited the excellent physicochemical properties of hydrogel materials to develop a new novel interpenetrating hydrogel network structure as a culture framework, and 3D cell culture and tissue induction culture were combined to culture 3D muscle tissue in hydrogel environment and induce differentiation into muscle tissue. The results successfully induce cell proliferation, differentiation and myotube formation in vitro, provide a new idea for the rapid cultivation of muscle tissue in vitro and provide a basis for the assembly of soft robots in the future.

Enhanced flexibility of high-yield bamboo pulp fibers via cellulase immobilization within guar gum/polyacrylamide/polydopamine interpenetrating network hydrogels

Softness is a crucial criterion in assessing the comfort and usability of tissue paper. Flexible fibers contribute to the softness of the tissue paper by allowing the sheets to conform to the contours of the skin without feeling rough or abrasive. This study focuses on developing innovative CGG/APAM/PDA hydrogels with interpenetrating networks consisting of cationic guar gum, anionic polyacrylamide, and polydopamine for cellulase immobilization, aimed at improving bamboo fiber flexibility. Cellulase biomolecules are efficiently immobilized on CGG/APAM/PDA hydrogels through the Schiff base reaction. Immobilized cellulases have a wider pH applicability than free cellulases, good storage stability, and can maintain high relative activity at relatively high temperatures. The treatment of bamboo fibers with immobilized cellulase results in a significant increase in flexibility, reaching 6.90 × 1014 N·m2, which is 7.18 times higher than that of untreated fibers. The immobilization of cellulases using CGG/APAM/PDA hydrogels as carriers results in a substantial enhancement of storage stability, pH applicability, and inter-fiber bonding strength, as well as the capacity to sustain high relative enzymatic activity at elevated temperatures. The immobilization of cellulase within CGG/APAM/PDA interpenetrating network hydrogels presents a viable strategy for enhancing bamboo fiber flexibility, thereby expanding the accessibility of tissue products.

Development of interpenetrating network hydrogels: Enhancing the release and bioaccessibility of green tea polyphenols

Green Tea polyphenols (GTP) are important bioactive compounds with excellent physiological regulation functions. However, they are easily destroyed by the gastric environment during digestion. In this work, a sodium alginate (SA)-gellan gum (GG) interpenetrating network (IPN) hydrogel was synthesized to protect and delivery GTP. The ratio of SA/GG significantly affects the network structure of IPN hydrogels and the performance of delivering GTP. The hydrogel formed by interpenetrating 20 % GG with 80 % SA as the main network had the highest water uptake (55 g/g), holding capacity (950 mg/g), and freeze-thaw stability, with springiness reaching 0.933 and hardness reaching 1300 g, which due to the filling effect and non-covalent interaction. Rheological tests showed that the crosslink density of IPN hydrogel in SA-dominated network was improved by the addition of GG to make it better bound to GTP, and the higher water uptake meant that the system could absorb more GTP-containing solution. This IPN hydrogel maintained 917.3 mg/g encapsulation efficiency at the highest loading capacity (1080 mg/g) in tests as delivery system. In in vitro digestion simulations, owing to the pH responsiveness, the IPN hydrogel reduced the loss of GTP in gastric fluid, achieving a bioaccessibility of 71.6 % in the intestinal tract.

Localized Ionic Reinforcement of Double Network Granular Hydrogels.

Nature produces soft materials with fascinating combinations of mechanical properties. For example, the mussel byssus embodies a combination of stiffness and toughness, a feature that is unmatched by synthetic hydrogels. Key to enabling these excellent mechanical properties are the well-defined structures of natural materials and their compositions controlled on lengths scales down to tens of nanometers. The composition of synthetic materials can be controlled on a micrometer length scale if processed into densely packed microgels. However, these microgels are typically soft. Microgels can be stiffened by enhancing interactions between particles, for example through the formation of covalent bonds between their surfaces or a second interpenetrating hydrogel network. Nonetheless, changes in the composition of these synthetic materials occur on a micrometer length scale. Here, 3D printable load-bearing granular hydrogels are introduced whose composition changes on the tens of nanometer length scale. The hydrogels are composed of jammed microgels encompassing tens of nm-sized ionically reinforced domains that increase the stiffness of double network granular hydrogels up to 18-fold. The printability of the ink and the local reinforcement of the resulting granular hydrogels are leveraged to 3D print a butterfly with composition and structural changes on a tens of nanometer length scale.

Wrecking neutrophil extracellular traps and antagonizing cancer-associated neurotransmitters by interpenetrating network hydrogels prevent postsurgical cancer relapse and metastases

Tumor-promoting niche after incomplete surgery resection (SR) can lead to more aggressive local progression and distant metastasis with augmented angiogenesis-immunosuppressive tumor microenvironment (TME). Herein, elevated neutrophil extracellular traps (NETs) and cancer-associated neurotransmitters (CANTs, e.g., catecholamines) are firstly identified as two of the dominant inducements. Further, an injectable fibrin-alginate hydrogel with high tissue adhesion has been constructed to specifically co-deliver NETs inhibitor (DNase I)-encapsulated PLGA nanoparticles and an unselective β-adrenergic receptor blocker (propranolol). The two components (i.e., fibrin and alginate) can respond to two triggers (thrombin and Ca2+, respectively) in postoperative bleeding to gelate, shaping into an interpenetrating network (IPN) featuring high strength. The continuous release of DNase I and PR can wreck NETs and antagonize catecholamines to decrease microvessel density, blockade myeloid-derived suppressor cells, secrete various proinflammatory cytokines, potentiate natural killer cell function and hamper cytotoxic T cell exhaustion. The reprogrammed TME significantly suppress locally residual and distant tumors, induce strong immune memory effects and thus inhibit lung metastasis. Thus, targetedly degrading NETs and blocking CANTs enabled by this in-situ IPN-based hydrogel drug depot provides a simple and efficient approach against SR-induced cancer recurrence and metastasis.

Underwater sensors based on dual dynamically crosslinked hydrogels with excellent anti-swelling and adhesive properties

Hydrogel-derived flexible sensors have fascinating applications in the fields of wearable electronics and electronic skin. Nevertheless, the fabrication of underwater sensors is still restricted due to the underwater instability and the poor adhesion in an aquatic environment. In this work, a dynamic physical/chemical dual crosslinked poly (acrylic acid-co-lauryl methacrylate) and polyvinyl alcohol interpenetrating network hydrogel was successfully prepared to overcome the above issues. The as-prepared hydrogels exhibited prior stretchability (2310 % strain), good self-healing performance (83 % healing efficiency within 36 h), remarkable underwater instability (23 % of equilibrium swelling ratio), and long-term underwater adhesion (65.4 kPa of adhesive strength in water for 24 h). The as-prepared hydrogel strain sensor features excellent sensing performance (GF = 4.83) and a wide sensing range of 1%–1000 %. Due to its excellent flexibility, strong adhesion, and high strain sensitivity, the prepared hydrogel can be conveniently used for the real-time monitoring of various human movements, including pronounced joint movements and subtle muscle vibrations. Furthermore, the hydrogel-based sensor with good and stable mechanical, electrical, and adhesive properties in an aquatic environment can accomplish effective signal transmission underwater via the combination of body movement and the Morse code.

In vitro and in vivo investigation of chitosan/silk fibroin injectable interpenetrating network hydrogel with microspheres for cartilage regeneration

Articular cartilage is an avascular and almost acellular tissue with limited self-regenerating capabilities. Although injectable hydrogels have garnered a lot of attention as a promising treatment, a biocompatible hydrogel with adequate mechanical properties is yet to be created. In this study, an interpenetrating network hydrogel comprised of chitosan and silk fibroin was created through electrostatic and hydrophobic bonds, respectively. The polymeric network of the scaffold combined an effective microenvironment for cell activity with enhanced mechanical properties to address the current issues in cartilage scaffolds. Furthermore, microspheres (MS) were utilized for a controlled release of methylprednisolone acetate (MPA), around ~75 % after 35 days. The proposed scaffolds demonstrated great mechanical stability with ~0.047 MPa compressive moduli and ~145 kPa compressive strength. Moreover, the degradation rate of the samples (~45 % after 35 days) was optimized to match neo-cartilage formation. Furthermore, the use of natural biomaterials yielded good biocompatibility with ~76 % chondrocyte viability after 7 days. According to gross observation after 12 weeks the defect site of the treated groups was filled with minimally discernible boundary. These results were confirmed by histopathology assays were the treated groups showed higher chondrocyte count and collagen type II expression.

Interpenetrating network based on soybean protein isolate and carboxymethyl chitosan: Investigation of intermolecular reaction mechanism, physicochemical stability and in vitro release properties of the hydrogel

In this study, interpenetrating network (IPN) hydrogels were constructed from soybean protein isolate (SPI) and carboxymethyl chitosan (CMCS) using TGase and genipin (GP) as cross-linking agents. And the influence of IPN formation on the physicochemical properties of hydrogels was illuminated. Multispectral analyses showed that there was a strong interaction between SPI and CMCS, which also promoted the increase of disulfide bonds and hydrophobic interactions in the hydrogels. The IPN was the densest when the addtion of SPI and CMCS were 10% and 3%, respectively. Meanwhile, this structure endowed the hydrogels with good mechanical properties and allowed them to exhibit thixotropy in rheological tests. The LF-NMR results showed that the IPN had a strong binding ability with water molecules and could effectively maintain the water in the hydrogel after freeze-thaw. Moreover, SPI-CMCS IPN hydrogels were pH responsive. This enabled it to adjust its own structure when pH changed, and to achieve controlled release of bioactives during simulated in vitro digestion. Overall, the results of this study showed that the IPN network formed by SPI and CMCS can effectively improve the performance of hydrogel. These results demonstrated the potential of SPI and CMCS as hydrogel synthesizers and provided a theoretical basis for the application of SPI-CMCS IPN hydrogel.

Review of the feasibility of a new touch-sensitive digital display enabled by block copolymer materials

Nowadays, electronic devices are widely used, and as an important part of many electronic devices, human-computer interaction displays have a lot of room for development. At present, traditional touch displays typically incorporate materials such as indium tin oxide (ITO) or graphene, which have limitations such as inflexibility, average accuracy and needing external power supplies. This article describes a motion sensor without additional power supply, which is based on one-dimensional photonic crystals of interpenetrating hydrogel network block copolymer (IHN-BCP), composed of photonic crystals alternating between different layers. The article concentrates on the viability of addressing these difficulties. The result shows that Block copolymers are unique polymers consisting of two or more distinct polymer chains, with the potential to exhibit self-assembling behaviour. Due to the special properties of block copolymer, this display could have flexible substrates and detect various contact and non-contact human motions. This device can be applied to interactive screens for cell phone screens, factory equipment, and other electronic products, and can also provide a reference for the future development of flexible screens.