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ACS Nano Jun 2024Elastic electromagnetic fibers are promising building blocks for next-generation flexible electronics. However, fabrication of elastic fibers is still difficult and...
Elastic electromagnetic fibers are promising building blocks for next-generation flexible electronics. However, fabrication of elastic fibers is still difficult and usually requires organic solvents or high temperatures, restricting their widespread applications. Furthermore, the continuous production of electromagnetic fibers has not been realized previously. In this study, we propose an ionic chelation strategy to continuously produce electromagnetic fibers with a magnetic liquid metal (MLM) as the core and elastic polyurethane as the sheath in water at room temperature. Sodium alginate (SA) has been introduced to rapidly chelate with calcium ions (Ca) in a coagulation bath to support the continuous spinning of waterborne polyurethane (WPU) as a sheath. Meanwhile, WPU-encapsulated MLM microparticles efficiently suppress the fluid instability of MLM for continuous extrusion as the core. The resultant fiber exhibits excellent mechanical performances (tensile strength and toughness up to 32 MPa and 124 MJ/m, respectively), high conductive stability in large deformations (high conductivity of 7.6 × 10 S/m at 580% strain), and magnetoactive properties. The applications of this electromagnetic fiber have been demonstrated by conductance-stable wires, sensors, actuation, and electromagnetic interference shielding. This work offers a water-based molecular principle for efficient and green fabrication of multifunctional fibers and will inspire a series of applications.
PubMed: 38916583
DOI: 10.1021/acsnano.4c04455 -
RSC Advances Jun 2024Advances in high-efficiency solar cells introduce photon management challenges, including the difficult texturization of flat surfaces and low photon utilization at...
Advances in high-efficiency solar cells introduce photon management challenges, including the difficult texturization of flat surfaces and low photon utilization at short wavelengths. While bifacial crystalline silicon solar cells have a front pyramid structure and SiN layers reduce reflections, managing photons on the flat backside remains a challenge. To enhance light utilization, a soft nanoimprint technique was utilized to create pyramid micro-structured polyurethane films doped with europium (Eu) complex. These films, which possess anti-reflection and down-conversion properties, can be applied externally to various high-efficiency solar cells without compromising electrical performance. Research on the backside of bifacial PERC solar cells revealed that the optimal composite functional film increases the integrated current by 5.70%, with a 1.27% gain from down-conversion effects. This specialized film presents a novel approach to interface matching for different types of solar cells.
PubMed: 38915332
DOI: 10.1039/d4ra03397c -
Journal of Materials Chemistry. B Jun 2024Postoperative adhesions, a prevalent complication following abdominal surgery, affect 90% of patients undergoing abdominal surgical procedures. Currently, the primary...
Postoperative adhesions, a prevalent complication following abdominal surgery, affect 90% of patients undergoing abdominal surgical procedures. Currently, the primary approach to prevent postoperative adhesions involves physical isolation of the surgical site and surrounding tissues using a hydrogel; however, this method represents a rudimentary strategy. Herein, considering the impact of oxidative stress and free radicals on postoperative adhesion during wound healing, an injectable antioxidant hydrogel, named PU-OHA-D, was successfully synthesized, which is formed by the crosslinking of dopamine-modified oxidized hyaluronic acid (OHA-D) and dihydrazide-terminated polyurethane (PU-ADH) through hydrazone bonding. PU-OHA-D hydrogel possesses versatile characteristics such as rapid gel formation, injectability, self-repair capability and biodegradability. Additionally, they exhibit an excellent ability to clear free radicals and superior tissue adhesion. PU-OHA-D can be injected to form a hydrogel to prevent abdominal wall-cecum adhesion. Importantly, it can effectively eliminate free radicals and inhibit oxidative stress at the wound site. Thereby, it leads to collagen physiological degradation and prevents the occurrence of postoperative adhesions. The bioinspired hydrogel demonstrates its great potential in preventing postoperative adhesion and promoting wound healing.
PubMed: 38915270
DOI: 10.1039/d4tb00805g -
ACS Applied Materials & Interfaces Jun 2024Developing fabric-based strain sensors with high sensitivity and stability is in high demand for wearable electronics. Herein, carbon nanotubes (CNTs) and polypyrrole...
Developing fabric-based strain sensors with high sensitivity and stability is in high demand for wearable electronics. Herein, carbon nanotubes (CNTs) and polypyrrole (PPy) are coated on a thermoplastic polyurethane (TPU) fabric as strain sensors. A microbridge structure, in which CNT bridges the stretching-induced cracks, has been designed for the TPU-CNT-PPy strain sensor. The microbridge structure can significantly enhance the electrical resilience, ensuring the improved sensitivity and stability of strain sensors. As a result, our TPU-CNT-PPy strain sensors deliver high sensitivity (GF = 231.5) with a broad working range (150%) and fast response and recovery time (166/195 ms). In addition, our TPU-CNT-PPy could also be used as flexible electrodes of the microsupercapacitors (MSCs) as a power supplier for the integrated sensing system. The TPU-CNT-PPy-based MSCs exhibit a high specific capacitance (460.3 mF cm at 0.5 mA cm) and excellent cycling stability (96.69% capacitance retention for 10,000 charge/discharge cycles). Finally, we demonstrated an integrated sensing system using TPU-CNT-PPy as both MSCs and strain sensors, where the current signals of the sensors could be well detected via Bluetooth. This study offers a microbridge strategy to fabricate strain sensors with high sensitivity and stability and develops an integrated sensing system for the actual applications of wearable electronics.
PubMed: 38914520
DOI: 10.1021/acsami.4c05753 -
Materials Horizons Jun 2024It is challenging for ionic liquid gels to achieve the combination of rapid self-healing with high toughness. Here, ionic liquid gels (DI-PR) were prepared from readily...
It is challenging for ionic liquid gels to achieve the combination of rapid self-healing with high toughness. Here, ionic liquid gels (DI-PR) were prepared from readily available materials. A dynamic covalently bonded oxime-carbamate was prepared from polycaprolactone diol, isophorone diisocyanate and dimethylethyleneglyoxime, followed by addition of the "rigid-flexible" cross-linking agent rutin to chemically cross-link the polymer chains and afford the ionic liquid gels, DI-PR. The tensile strength, elongation at break and toughness of the DI-PR gels were as high as 16.5 MPa, 1132.6%, and 52.6 MJ m, respectively. The toughness is similar to that of natural silkworm silk (70 MJ m) and wool (60 MJ m). After stretching, the DI-PR can rebound within 1 s, their room temperature self-healing rate is as high as 92%, they remain functional over the temperature range -50 °C to 140 °C and the interface with a steel plate has an adhesion toughness of >2000 J m. These properties mean that the DI-PR gels are particularly suitable for use as anticorrosion coatings for submarine and underground gas and oil pipelines. The use of rutin, which combines rigid quercetin-based structural units with flexible glycoside-based structural units, as a cross-linking agent, provides a new method for improving the toughness of soft materials through its synergistic interaction with hard and soft chain fragments of polyurethanes.
PubMed: 38910542
DOI: 10.1039/d4mh00497c -
Journal of Zhejiang University.... Jun 2024Artificial vascular graft (AVG) fistula is widely used for hemodialysis treatment in patients with renal failure. However, it has poor elasticity and compliance, leading...
Artificial vascular graft (AVG) fistula is widely used for hemodialysis treatment in patients with renal failure. However, it has poor elasticity and compliance, leading to stenosis and thrombosis. The ideal artificial blood vessel for dialysis should replicate the structure and components of a real artery, which is primarily maintained by collagen in the extracellular matrix (ECM) of arterial cells. Studies have revealed that in hepatitis B virus (HBV)-induced liver fibrosis, hepatic stellate cells (HSCs) become hyperactive and produce excessive ECM fibers. Furthermore, mechanical stimulation can encourage ECM secretion and remodeling of a fiber structure. Based on the above factors, we transfected HSCs with the hepatitis B viral X () gene for simulating the process of HBV infection. Subsequently, these -HSCs were implanted into a polycaprolactone-polyurethane (PCL-PU) bilayer scaffold in which the inner layer is dense and the outer layer consists of pores, which was mechanically stimulated to promote the secretion of collagen nanofiber from the -HSCs and to facilitate crosslinking with the scaffold. We obtained an ECM-PCL-PU composite bionic blood vessel that could act as access for dialysis after decellularization. Then, the vessel scaffold was implanted into a rabbit's neck arteriovenous fistula model. It exhibited strong tensile strength and smooth blood flow and formed autologous blood vessels in the rabbit's body. Our study demonstrates the use of human cells to create biomimetic dialysis blood vessels, providing a novel approach for creating clinical vascular access for dialysis.
Topics: Rabbits; Animals; Hepatic Stellate Cells; Renal Dialysis; Polyesters; Viral Regulatory and Accessory Proteins; Tissue Scaffolds; Transfection; Bionics; Polyurethanes; Blood Vessel Prosthesis; Extracellular Matrix; Humans; Hepatitis B virus; Collagen; Tissue Engineering; Trans-Activators
PubMed: 38910495
DOI: 10.1631/jzus.B2300479 -
Journal of Chromatography. A Jun 2024In this research, electrospun nanofibers based on copper-based metal organic framework (MOF)/polyurethane (PU) were prepared in order to achieve an applicable and...
In this research, electrospun nanofibers based on copper-based metal organic framework (MOF)/polyurethane (PU) were prepared in order to achieve an applicable and superior extractive phase. The incorporation of MOF, in the synthesized nanocomposite contributed to the enhanced sorption efficiency. The prepared sorbent was implemented for the thin film microextraction (TFME) of target compounds with subsequent quantification using gas chromatography-mass spectrometry (GC-MS). To obtain the maximum efficiency of the synthesized sorbent, the influential parameters on extraction and desorption steps, including the MOF percentage in nanocomposite, desorption solvent type and its volume, desorption time, solution ionic strength and extraction time were optimized. After method development, the linear dynamic range (0.02-700 μg L), limits of detection (LODs) (0.005-0.1 μg L) and limits of quantification (LOQs))0.02-0.33 μg L(were calculated. The relative standard deviations values for intra-day and inter-day analysis were found to be in the range of 4.3-5.3 % and 6.2-8.1 %, respectively. The developed method was validated for the TFME of model organochlorine (OC) pesticide residues in fish, soil and water samples. the recovery values for the spiked samples at two concentration levels of 5 and 100 µg l were found in the range of 72-110 %.
PubMed: 38909520
DOI: 10.1016/j.chroma.2024.465061 -
ACS Nano Jun 2024Smart textiles capable of both energy harvesting and multifunctional sensing are highly desirable for next-generation portable electronics. However, there are still...
Smart textiles capable of both energy harvesting and multifunctional sensing are highly desirable for next-generation portable electronics. However, there are still challenges that need to be conquered, such as the innovation of an energy-harvesting model and the optimization of interface bonding between fibers and active materials. Herein, inspired by the spiral structure of natural vines, a highly stretchable triboelectric helical yarn (TEHY) was manufactured by twisting the carbon nanotube/polyurethane nanofiber (CNT/PU NF) Janus membrane. The TEHY had a zebra-stripe-like design that was composed of black interval conductive CNTs and white insulative PU NFs. Due to the different electron affinity, the zebra-patterned TEHY realized a self-frictional triboelectric effect because the numerous microscopic CNT/PU triboelectric interfaces generated an alternating current in the external conductive circuit without extra external friction layers. The helical geometry combined with the elastic PU matrix endowed TEHY with superelastic stretchability and outstanding output stability after 1000 cycles of the stretch-release test. By virtue of the robust mechanical and electrical stability, the TEHY can not only be used as a high-entropy mechanical energy harvester but also serve as a self-powered sensor to monitor the stretching or deforming stimuli and human physiological activities in real time. These merits manifested the versatile applications of TEHY in smart fabrics, wearable power supplies, and human-machine interactions.
PubMed: 38907712
DOI: 10.1021/acsnano.4c03115 -
Medical Engineering & Physics Jul 2024Anchorage, evaluated by the maximum insertion torque (IT), refers to mechanical engagement between dental implant and host bone at the time of insertion without external...
Anchorage, evaluated by the maximum insertion torque (IT), refers to mechanical engagement between dental implant and host bone at the time of insertion without external loads. Sufficient anchorage has been highly recommended in the clinic. In several studies, the effects of implant diameter and taper body design under external loading have been evaluated after insertion; however, there are few studies, in which their effects on stress distribution during insertion have been investigated to understand establishment of anchorage. Therefore, the objective of this study was to investigate the effects of dental implant diameter and tapered body design on anchorage combining experiments, analytical modeling, and finite element analysis (FEA). Two implant designs (parallel-walled and tapered) with two implant diameters were inserted into rigid polyurethane (PU) foam with corresponding straight drill protocols. The IT was fit to the analytical model (R = 0.88-1.0). The insertion process was modeled using explicit FEA. For parallel-walled implants, normalized IT and final FEA contact ratio were not related to the implant diameter while the implant diameter affected normalized IT (R = 0.90, p < 0.05, β = 0.20 and β = 0.93, standardized regression coefficients for implant diameter and taper body design) and final FEA contact ratio of tapered implants. The taper design distributed the PU foam stress further away from the thread compared to parallel-walled implants, which demonstrated compression in PU foam established by the tapered body during insertion.
Topics: Polyurethanes; Dental Implants; Finite Element Analysis; Stress, Mechanical; Torque; Materials Testing
PubMed: 38906568
DOI: 10.1016/j.medengphy.2024.104181 -
International Journal of Biological... Jun 2024In order to fulfill the demands for degradability, a broad working range, and heightened sensitivity in flexible sensors, biodegradable polyurethane (BTPU) was...
Biodegradable poly(lactic acid) blocked polyurethane/carbon nanotubes coated cotton fabric prepared by ultrasonic-assisted inkjet printing for high performance strain sensors.
In order to fulfill the demands for degradability, a broad working range, and heightened sensitivity in flexible sensors, biodegradable polyurethane (BTPU) was synthesized and combined with CNTs to produce BTPU/CNTs coated cotton fabric using an ultrasonic-assisted inkjet printing process. The synthesized BTPU displayed a capacity for degradation in a phosphate buffered saline solution, resulting in a weight loss of 25 % after 12 weeks of degradation. The BTPU/CNTs coated cotton fabric sensor achieved an extensive strain sensing range of 0-137.5 %, characterized by high linearity and a notable sensitivity (gauge factor (GF) of 126.8). Notably, it demonstrated a low strain detection limit (1 %), rapid response (within 280 ms), and robust durability, enabling precise monitoring of both large and subtle human body movements such as finger, wrist, neck, and knee bending, as well as swallowing. Moreover, the BTPU/CNTs coated cotton fabric exhibited favorable biocompatibility with human epidermis, enabling potential applications as wearable skin-contact sensors. This work provides insight into the development of degradable and high sensing performance sensors suitable for applications in electronic skins and health monitoring devices.
PubMed: 38906353
DOI: 10.1016/j.ijbiomac.2024.133269