Electrical Conductivity Properties Research Articles

Magnetron-Sputtered Long-Term Superhydrophilic Thin Films for Use in Solid-State Cooling Devices

Pulse-magnetron-sputtered long-term superhydrophilic coatings have been synthesized to functionalize the surfaces of solid-state cooling devices, e.g., electrocaloric heat pumps, where not only a complete wetting of the surface by a fluid is intended, but also fast wetting and dewetting processes are required. The coatings consist of a (Ti,Si)O2 outer layer that provides lasting hydrophilicity thanks to the mesoporous structure, followed by an intermediate WO3 film that enables the reactivation of the wettability through visible light irradiation, and a W underlayer which can work as a top electrode of the electrocaloric components thanks to its suitable electrical and thermal conductivity properties. Process parameter optimization for each layer of the stack as well as the influence of the microstructure and composition on the wetting properties are presented. Finally, water contact angle measurements, surface energy evaluations, and a contact line dynamics assessment of evaporating drops on the coatings demonstrate that their enhanced wetting performance is attributed not only to their intrinsic hydrophilic nature but also to their porous microstructure, which promotes wicking and spreading at the nanometric scale.

Coal-derived conductive pavement for winter de-icing: prototype, modeling, and simulation

Existing pavement de-icing methods result in high installation and maintenance costs, traffic delays, excessive weariness and corrosion, and negative environmental and safety impacts. To overcome these challenges, this paper presents an innovative pathway to design and construct smart self-heating pavements using a low-cost coal-char bearing asphalt material. The conductive asphalt incorporates coal char, i.e., a key byproduct of the coal pyrolysis process, into the Stone Mastic Asphalt (SMA) mixture. This asphalt containing coal-derived solid carbon exhibits highly tailorable electrical conductivity, satisfactory mechanical and thermophysical properties, and superior cost-efficiency as compared to other conductive pavement materials. The de-icing performance was also demonstrated by laboratory experiments on a bench-scale prototype. Furthermore, an efficient thermal network model was developed and validated by experiments to investigate the transient thermal behavior and energy performance of the Ohmic heating pavement system. The whole-year energy simulation case studies were conducted on a bridge pavement with an annual energy use of 24.6–––1444.8 kWh/m2, showcasing its potential in field applications across cool humid, cold humid, and subarctic/arctic climate zones

Role of cyclodextrin inclusion complexes assembled in the fast-dissolving structures of electrospun gelatin mats to extend the release of menthol

In this study, inclusion complexes (ICs) of menthol with various cyclodextrins (CDs) [α-CD, β-CD, γ-CD, (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD), and methyl-β-cyclodextrin (M-β-CD)] were prepared first, and then the ICs with the highest encapsulation efficiency were applied in electrospun gelatin mats to extend release of menthol. Electrospinning feed solutions in terms of surface tension, zeta potential, electrical conductivity, and rheological properties were evaluated. The diameter and morphology of the pure gelatin and the CDs-loaded gelatin mats were analyzed using microscopy (FESEM and AFM), which confirms that CDs loading leads to a decrease in the diameter of the nanofibers. The longest disintegration time belonged to the gelatin mat containing the β-CD complex. Comparison of the FTIR spectrum and XRD patterns of gelatin mats containing menthol-loaded CD complexes with the pure compounds confirmed the successful encapsulation of menthol inside the cavity of the CD, and also the disappearance of the crystalline state of electrospun gelatin mats. Applying the electrospun gelatin mats as a fast-dissolving structure for the menthol-loaded inclusion complexes increased its thermal stability. In the bioadhesieve test, the lowest force required to separate the gelatin mat from the skin model was obtained in the menthol-containing β-CD gelatin mat (6.21± 1.01 g). The menthol release from the pure gelatin mats was much faster than the electrospun mats containing CDs complexes, however the menthol-loaded β-CD gelatin mat showed the slowest release into the simulated saliva. Peppas-Sahlin and Fickian diffusion (Case-I) were the best-fitted model and menthol release mechanism, respectively.

Effects of Cr2O3 doping on crystallization behavior and electrochemical properties of Li2O–Al2O3–TiO2–P2O5–SiO2 glass-ceramics

Bulk glass-ceramic solid electrolytes of the Li2O–Al2O3–TiO2–P2O5–SiO2 system were prepared by melt-quenching and one-step heat treatment method in this work. The effects of the gradual substitution of Al3+ by Cr3+ and the elevation of the heat treatment temperature on the phase composition, microstructure, and ionic conductivity of the solid electrolytes were systematically investigated. The results show that the major crystalline phase is LiTi2(PO4)3, and the conductivity of the glass-ceramics initially enhances and then decreases as the Cr2O3 content increases from 0 mol% to 3 mol%. The highest conductivity is obtained when the Cr2O3 content is 2 mol%, measuring 4.45 × 10−4 S/cm at 25 °C. Additionally, the mechanism of the surface exfoliation of the glass-ceramics and the enhancement achieved by doping with Cr3+ are explained according to microstructure analysis. This work provides a simple method to enhance the electrical conductivity and physical properties of LATP glass-ceramic solid electrolytes, which is of great significance for the design of lithium-ion solid electrolytes.

Dielectric, electrical and thermal properties of Sodium Molybdate-hexagonal Boron Nitride composites enabled by cold sintering

Advances in 5G and 6G communication technologies and their applications are in part limited by the capabilities of current electronic packaging materials, as expanded bandwidth is a pressing need for novel dielectric substrates capable of co-firing into packages and devices, characterized by low dielectric loss and enhanced thermal conductivity. This investigation provides further characterization in the dielectric, electrical and thermal conductivity properties over previously reported cold sintered composite of Sodium Molybdate Na2Mo2O7 (NMO) with hexagonal Boron Nitride (hBN), such as relative permittivity (εr) and dielectric loss (tan δ) values at high frequencies of 75–110 GHz, electrical resistivity (ρ) fitting to percolation theory, Weibull statistical analysis of electrical breakdown strength (Eb) and its anisotropic thermal conductivity (κ) influenced by the filler's crystal structure. The cold sintered composites were systematically characterized with respect to filler volume fraction, temperature, and frequency. The findings in this analysis position engineered composites as a promising alternative for microwave substrate materials, with using a densification method that limits interactions and maximizes densification, hence the demonstration with cold sintering.

Non-amphoteric N-type doping with Sn of GaAs(631) layers grown by molecular beam epitaxy

The Sn-doping effects on the electrical conduction and optical properties of GaAs(631)A epilayers grown by molecular beam epitaxy were investigated. We found that the conduction type conversion, frequently observed in the doping of layers grown on high-index substrates, is avoided when tin-doping is implemented. The maximum free-carrier concentration (n) obtained in GaAs(631):Sn was 2 × 1019 cm−3, an order of magnitude higher than previously reported for GaAs(631):Si, and within the same order of magnitude for the growth of GaAs(100):Si. The electron mobility was suitable for many optoelectronic applications. Raman spectroscopy showed low lattice disorder in (631) oriented samples, compared with singular (100) samples. The photoluminescence characterization of the samples revealed the blueshift of the optical transitions close to E0 associated with the Moss–Burstein effect for Sn doping. Photoreflectance spectroscopy was used to study the doping properties at the critical points E1 and E1 + Δ1, where the major affectation with n was perceived in the broadening parameter Γ.

Effect of Silicone Rubber on the Properties of Epoxy/Recovered Carbon Black (rCB) Conductive Materials

The primary focus of this study is to investigate the effect of silicone rubber (SR) content on the mechanical, thermal, electrical conductivity, and morphological properties of epoxy/recovered carbon black (rCB) conductive material. The conductive material is used to produce the electrostatic discharge (ESD) tray for the electronic packaging industry. This study investigated the effect of silicone rubber content (0, 5, 10, 15, and 20 vol.%) on the properties of epoxy/SR/rCB conductive materials, with the rCB content fixed at 15 vol.% for its optimum electrical conductivity. The silicone rubber acts as a toughening agent for epoxy. Through the fracture toughness result, it can be identified that silicone rubber plays a role in improving the toughness properties of the epoxy/SR/rCB conductive material. The optimum results for mechanical properties were recorded at 5 vol.% SR. The addition of SR to the epoxy matrix enhances the electrical properties of the epoxy/SR/rCB conductive material. The effect of thermal aging on epoxy/SR/rCB conductive materials was also studied to determine the properties of the conductive material materials at high temperatures for a long period of time. After thermal aging, the mechanical, thermal, electrical conductivity, and morphological properties of the epoxy/SR/rCB conductive material were slightly reduced.

Zero-emission hydrogen production by CH4 pyrolysis over Ni/Ferrierite catalyst: Examination of the deactivated catalysts for electrical conductivity and H2 storage properties

An economic route for the generation of hydrogen and utilization of carbon nanofibers (CNFs) was achieved by CH4 cracking over 20 wt%Ni/FER catalyst. The deactivated catalyst demonstrated electrical conductivity and hydrogen storage properties. TEM images displayed open mouths of CNFs and XRF data showed nearly 70% of nickel was recovered from the deactivated catalyst. Impedance studies of the CNFs exhibit prominence as battery electrodes due to their significant conductivity in the presence of nickel. While the hydrogen storage capacity was around 0.151 mmol (gcat)−1 of H2 on the obtained CNFs, it was increased to 0.361 mmol (gcat)−1 upon Ni recovery from the CNFs. A seven-fold increase in the H2 storage of ∼0.862 mmol (gcat)−1 was obtained upon Li doping, exhibiting its distinct property as a hydrogen storage material. The fresh, reduced, used, and deactivated catalysts were characterized by BET-SA, H2-TPR, XRD, Raman spectroscopy, TEM, and H2 pulse chemisorption and Ni/FER was established as an economically viable catalyst for high rates of H2 and CNF production.

Advances in carbon fiber-based electromagnetic shielding materials: Composition, structure, and application

With the swift advancement of wireless communication technology, there is increasing concern regarding the potential hazards posed by electromagnetic radiation emitted from various electronic devices. Carbon fiber (CF)-based composites have emerged as a vital component in structure function integrated electromagnetic interference (EMI) shielding research, attributable to their exceptional electrical conductivity and mechanical properties. This review summarizes recent research advances in CF-based composites for EMI shielding. Initially, it explores the influence of factors such as the geometric form of CFs on their EMI shielding properties. Since CF is inefficient when used alone for EMI shielding, so additional EMI filler materials are often introduced. Therefore, delves into an in-depth analysis of the reinforcement mechanisms provided by the incorporated second-phase materials, as well as the smart structural designs within the CF-based composites. On this basis, the applications of CF-based EMI shielding materials in the fields of thermal conductivity, flexible wearable technology, and aerospace are reviewed. Additionally, the review offers a perspective on the future development trends and prospects of CF-based composites in the field of EMI shielding based on the current research status.

Analyzing Tear Fluid Composition by Synchronous Fluorescence for Diagnosing Dry Eye Disease and the Role of Phytotherapy Intervention.

Tear fluid gained attention as a representative biological fluid. Its simple and non-invasive collection methods as well as richness of candidate biomarkers made it a potential diagnostic tool for different diseases such as dry eye. Synchronous fluorescence spectroscopy is a highly sensitive analytical tool that results in narrowing and enhanced peak resolution, and has a potential role in disease diagnosis, biomarker identification, and therapeutic monitoring. We applied synchronous fluorescence spectroscopy to monitor variations of tear fluid composition during the development of dry eye disease and to evaluate the potential effects of phytotherapy. Dry eye model was induced in Chinchilla rabbits by instillation of 1% atropine sulfate ophthalmic solution. Then, the tear fluid was collected at 3, 7, and 14days and subjected to synchronous fluorescence spectroscopy. Phytotherapy was achieved by topical instillation of 20µl of water extracts of pomegranate peel or green tea powders. The fluorescence results revealed changes in the structure of tear fluid over time and the eye is subjected to toxification due to oxidative stress. In addition, dry eye disease was found to affect the metabolic/energetic state of the eye. On the other hand, phytotherapy led to enhancement of the metabolic/biosynthesis state due to activation of flavin adenine dinucleotide-associated proteins. There was change in the electrical conductivity of tear fluid proteins. In the case of dry eyes, they became electrical insulators, while in the case of treatment with extracts, their electrical conductivity properties improved. The effects of phytotherapy can be related to the high content of ellagic acid and anthocyanin of pomegranate extract, while in green tea, they are related to catechins and phenolic compounds.

Investigation of alignment and layup optimization of recycled carbon fiber mats on mechanical and electromagnetic shielding properties of composites

AbstractExcellent recycled carbon fiber (rCF) was obtained using a thermally activated oxide semiconductor process. An alignment device was manufactured based on wet‐laid technology. It was used to investigate the effect of various alignment nozzle parameters on the degree of alignment of rCF mats. The mechanical, electrical conductivity and EMI shielding properties of composites reinforced by rCF mats with different layup structures were analyzed. The results showed that the optimal alignment parameters for rCF aligned mats included a convex nozzle shape, a nozzle diameter of 3 mm, a nozzle channel length of 50 mm, a nozzle up‐and‐down diameter ratio of 7:1, a nozzle departure height of 20 mm. These settings achieved a preferential alignment degree (PAD) of 93.07%. The design of layup structures for rCF mats with optimized fiber alignment fully exploits the material's anisotropic characteristics. The rCF‐0/EP composite material exhibited the highest tensile strength (195.45 MPa), while the rCF‐04/EP composite material not only demonstrated the highest flexural strength (247.95 MPa) but also showed excellent electromagnetic interference (EMI) performance (47.97 dB). The results of the research laid a theoretical foundation and provides scientific guidance for high‐value reuse of rCF.Highlights Utilized rCF as a reinforcing material for CFRP composites. Preparation of rCF aligned mats with high PAD. Effect of different layup structures on rCF aligned mat reinforced composites. rCF aligned mats improve mechanical properties and EMI properties of composites.

Evolution of microstructure and properties of Cu-Cr-Sn-Zr-Zn alloys with different Zn contents

Cu-Cr-Sn-Zr-xZn alloys with different Zn contents (0.087, 0.26, and 0.42 wt%) were prepared by vacuum casting, and the microstructure and properties of these alloys were investigated using different detection methods. The results show that the Zn element could promote the formation of some primary phase Cr particles and parts that were stretched into fibers during cold drawing deformation, thus enhancing the strength of these alloys. Meanwhile, the number of twins in these alloys increases with the increase in Zn content. When Zn content is 0.42%, the Cu0.64Zn0.36 phase is generated, which could play a role in the second phase’s strengthening. The Cu-0.97Cr-0.096Sn-0.068Zr-0.42Zn alloy shows high tensile strength and electrical conductivity properties of 832 MPa and 72%IACS, respectively.

Theoretical Study of the Phonon and Electrical Conductivity Properties of Pure and Sr-Doped LaMnO3 Thin Films.

The film thickness, temperature, substrate and doping dependence of the phonon energy ω and damping γ, as well as the electrical conductivity, of pure and Sr-doped LaMnO3 thin films near the phase transition temperature TN are investigated using a microscopic model and the Green's function technique. Due to the strong spin-phonon interaction, there appears a kink at TN in the temperature dependence of ω(T) and γ(T). The softening and hardening of the ω = 495 cm-1 (A1g) and ω = 614 cm-1 (B2g) modes is explained by the different sign of the anharmonic spin-phonon interaction constant R. The damping increases with T for both cases because it is proportional to R2. ω decreases whereas γ increases with an increasing Sr concentration. This is due to the strain caused by the difference between the ionic radii of the La and Sr ions. The film thickness dependence is also considered. ω and γ increase strongly with the decreasing film thickness. The electrical conductivity is enhanced after the doping of the LMO thin films with Sr, which could be used for energy storage applications. The observed results are in good qualitative agreement with the experimental data.

Two birds with one stone: A “needle-like” structure constructed on multifunctional PET fabric surface for flame retardancy and electromagnetic interference shielding

Here, a facile method is reported to prepare multifunctional PET fabrics with high flame retardancy, hydrophobicity and ideal electromagnetic shielding. PET fabric was firstly modified via polydopamine with mussel-like structure, and then DOPO@ZnO was constructed. A new type of composite PET fabric was prepared by simple, low-cost electroless Ni process and surface PDMS treatment (PpDPNP). The resulting composite fabric was extensively investigated for its stability and applicability in a complicated environment. The conductive interconnection network of modified fabric made it have excellent electrical conductivity and mechanical properties. Even after solution corrosion and washing, the prepared composite fabric could maintain a relatively stable electrical conductivity. The conductivity, tensile and elongation at break of composite fabric were 144.62 S/cm, 78.48 MPa and 167.49 %, respectively. The average electromagnetic interference shielding effectiveness (EMI SE) of PpDPNP reached 58.83 dB with 0.18 mm thickness and electroless Ni only 20 min at X-band, which was mainly due to large dielectric loss and multiple reflections. The modified PET fabric had self-extinguishing performance, and peak heat release rate (PHRR) and total heat release rate (THR) were 60.7 % and 59.8 % lower than pure PET fabric, respectively, indicating that the composite fabric had excellent flame retardancy.

MXene/Ag3PO4 modified PVDF composite membranes for efficient interfacial evaporation and photodegradation

Solar-powered interface evaporation is considered a promising technology to obtain freshwater from non-potable water by using sustainable solar energy. However, research on combining the photocatalytic effect with solar interfacial evaporation technology to go for photothermal conversion materials with full solar spectrum utilization for photothermal and photodegradation capabilities is still scarce. Due to the unique optical properties of MXene, a novel MXene/Ag3PO4-based membrane with synergistic photothermal and photocatalytic effects was developed from the perspective of practical applications such as water purification, photodegradation of organic dyes and antibacterial properties. In this paper, polyvinylidene fluoride (PVDF) and carbon black (CB) were used as the substrate, calcium carbonate (CaCO3) and hydrochloric acid (HCl) were selected as the pore-forming agent for hydrophilic modification, and MXene/Ag3PO4 serves as the photocatalyst. The prepared composite polyvinylidene fluoride membrane (PCC-MXene/Ag3PO4) with Schottky junction, possesses a rich pore structure, abundant water molecule transport channels, high light absorption ability, and low thermal conductivity, which lead to a good performance in solar interface evaporation, photodegradation and antibacterial. The superhydrophobicity and floatability of the nanosponges in water enable them to continuously pump water, which greatly promotes the dissolution of salt accumulation. With the help of porous nanosponges, PCC-MXene/Ag3PO4 exhibits excellent evaporation stability and salt resistance under 1 kW m−2 solar irradiation, as well as photodegradation of organic dyes. In addition, the PCC-MXene/Ag3PO4 membrane has the properties of self-buoyancy, electrical conductivity, and superior flexibility. Therefore, considering the simple preparation method and fine performances, the PCC-MXene/Ag3PO4 mixed membrane has great application potential in the study of interface evaporation, photodegradation of organic dyes, and antibacterial properties.

Substituent effect on the electronic and optical properties of newly designed pyrrole derivatives using density functional theory

Abstract This work explores six newly designed compounds obtained by several substitutions in 2,5-di(2-thienyl) pyrrole molecule. For this series of compounds, the electronic and optical properties were investigated using density functional theory and time-dependent density functional theory (TD-DFT). The new compounds were characterized by calculating the chemical parameters that correlated with their optical and electrical properties. The lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) energies are calculated using the B3LYP functional with the 6-311G (d, p) basis set. The most low-lying energy level of the LUMO was found for Perr-NO2, indicating its effective electron injection capabilities and oxidation resistance. The HOMO and LUMO distributions of Perr-Cl and Perr-NO2 displayed a remarkable complementarity throughout each component of the two compounds, indicating an effective intermolecular charge transfer. The molecular electrostatic potential analysis demonstrated that the proposed compounds have a broad distribution of electrophilic and nucleophilic sites, which predict a high degree of chemical reactivity. The electron density analysis at the bonding and anti-bonding sites of the title compounds was performed using the electron localization function and local orbital locator techniques. Non-covalent interaction analysis using the reduced density gradient approach classified all types of interaction: repulsive, weak, and attractive interactions within compound fragments. All compounds exhibited a robust repulsive interaction, as proved by the red spikes at 0.038 a.u. The ultraviolet/visible (UV/vis) spectrum was obtained by TD-DFT using CAM-B3LYP models in conjunction with 6-311G (d, p) basis set and methanol as a solvent, the absorption bands were found within the UV range, and the maximum wavelength showed red-shifted increases. These compounds could serve as a base material for developing selective gas sensors with considerable UV/vis absorption (180–400 nm). According to the research results, the designed compounds are good candidates for use as precursors in polymer designs for optoelectronic and sensor applications due to their high electrical conductivity and photochemical properties.

Characterization of electrical conductivity and dielectric properties of electroless NiP/rGO composite coated hemp fiber with various weight% of rGO and coating duration

The present study made an attempt to develop a conductive hemp fiber (HF) through an electroless Ni-P composite coating with reduced graphene oxide (rGO) as reinforcement. Four different Ni-P/rGO coated fibers were prepared with the variations in the coating time (20/40 min) and weight percentages of rGO (5/10 %). The coated fibers were characterized using various tools like: Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM), to identify the functional groups, phase structure, and morphological changes, induced by the rGO reinforcement. The coating duration and weight percentage of rGO had influenced the dielectric properties and electrical conductivity. In comparison, the coating duration of 40 min with 10 % addition of rGO has enhanced the electrical conductivity to 13.75 % and 37.5 % respectively. Furthermore, the mechanism behind the improvement in the conductivity is detailed in this study.

A Comprehensive Review of Fatigue Strength in Pure Copper Metals (DHP, OF, ETP)

Due to their exceptional electrical and thermal conductivity properties, high-purity copper (Cu-DHP) and copper alloys of similar composition, such as electrolytic tough-pitch (ETP), oxygen-free electronic (OFE) and oxygen-free (OF), have often been used in the manufacture of essential components for the electrical, electronic and power generation industries. Since these components are subject to cyclic loads in service, they can suffer progressive structural damage that causes failure due to fatigue. The purpose of this review is to examine the most relevant aspects of mechanical fatigue in Cu-DHP, ETP, OFE and OF. The impact of many factors on fatigue strength (Se), including the frequency, temperature, chemical environment, grain size, metallurgical condition and load type, were analyzed and discussed. Stress–life (S-N) curves under zero mean stress (σm = 0) were found for high-cycle fatigue (HCF). For non-zero mean stress (σm ≠ 0), stress curves were based on a combination of Gerber, Soderberg and ASME elliptic failure criteria. Stress–life (S-N) curves were also developed to correlate fatigue strength (Se) with stress amplitude (σa), yield strength (Syp) and ultimate strength (Sut). Finally, for low-cycle fatigue (LCF), strain–life (ε-N) curves that establish a relationship between the number of cycles to failure (N) and total strain amplitude (εplastic) were determined. Hence, this review, as well as the proposed curves, provide valuable information to understand fatigue failure for these types of materials.

Inkjet printed acrylate-urethane modified poly(3,4-ethylenedioxythiophene) flexible conductive films

Abstract Flexible electronics is a new generation of electronic devices in which electronic components are integrated into flexible substrates. It is used in the fabrication of displays, solar cells, integrated circuits, and increasingly in the fabrication of electronic skin (E-skin), which can mimic the properties of human skin by being able to follow skin movements and flexures without loss of mechanical and electrical properties. E-skin is suitable for integrating various sensors to monitor personal health. Conductive polymers are used in flexible electronics due to their electrical conductivity, low mass, and stability. However, their main disadvantage is their brittleness, which is why they don’t possess flexibility property without modification. Therefore, in this work, the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) was used as the main chain and the side branches of poly(acrylate-urethane) (PAU) were grafted onto it by atom transfer radical polymerization (ATRP) onto it, obtaining the grafted copolymer PEDOT-g-PAU. In this way, the main chain of PEDOT retains the property of electrical conductivity without losing conjugation, while the side branches of PAU have the ability to crosslink non-covalently through hydrogen bonds with PAU side branches of adjacent polymer molecules due to the presence of oxygen in their structure. The presence of hydrogen bonds allows increasing the stretchability and flexibility of the material, and they also have the ability to spontaneously renew themselves when they break due to excessive stress. Three different synthesis conditions were used to obtain polymers of different structure, which were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and measurement of electrical conductivity with a four-point probe (4PP) method. The obtained graft copolymer was prepared in the form of ink and printed on a polyurethane (PU) substrate using inkjet technique. The conductivity of the printed layer, its elongation and adhesion were investigated, while possible delamination of the printed polymer layer was also monitored. The results showed that the PEDOT-g-PAU copolymer was successfully synthesized and inkjet printing on PU film was successful. The obtained material has satisfactory electrical and mechanical properties and could be used for the integration of fully functional biosensors with further optimization of the composition.

A High-Stretching, Rapid-Self-Healing, and Printable Composite Hydrogel Based on Poly(Vinyl Alcohol), Nanocellulose, and Sodium Alginate.

Hydrogels with excellent flexibility, conductivity, and controllable mechanical properties are the current research hotspots in the field of biomaterial sensors. However, it is difficult for hydrogel sensors to regain their original function after being damaged, which limits their practical applications. Herein, a composite hydrogel (named SPBC) of poly(vinyl alcohol) (PVA)/sodium alginate (SA)/cellulose nanofibers (CNFs)/sodium borate tetrahydrate was synthesized, which has good self-healing, electrical conductivity, and excellent mechanical properties. The SPBC0.3 hydrogel demonstrates rapid self-healing (<30 s) and achieves mechanical properties of 33.92 kPa. Additionally, it exhibits high tensile strain performance (4000%). The abundant internal ions and functional groups of SPBC hydrogels provide support for the good electrical conductivity (0.62 S/cm) and electrical response properties. In addition, the SPBC hydrogel can be attached to surfaces such as fingers and wrists to monitor human movements in real time, and its good rheological property supports three-dimensional (3D) printing molding methods. In summary, this study successfully prepared a self-healing, conductive, printable, and mechanically superior SPBC hydrogel. Its suitability for 3D-printing personalized fabrication and outstanding sensor properties makes it a useful reference for hydrogels in wearable devices and human motion monitoring.