Composite Fibers Research Articles

Basalt/polypropylene composites: The effects of mechanical reprocessing on their morphological, thermal, rheological and mechanical behavior

Considering the increasing spread of basalt fibers on the market as bio-based alternative to glass and the massive use of polypropylene (PP) in the automotive sector, the end-of-life of PP/basalt composites through mechanical reprocessing was addressed. Their thermal, rheological and mechanical properties were investigated up to seven reprocessing cycles and the main relationship between their changes and composites fibers length reduction was disclosed. The composites displayed a parabolic increase in their melt volume rate for increasing reprocessing cycles and were characterized by an improved flowability compared to the neat matrix at the fifth cycle, i.e., 89.3 against 74.8 cm3/10min, due to the intimate contact between the fibers and the matrix which causes a stronger degradation in PP molecular weight. Concerning the mechanical response, the logarithmic decrease in stiffness and strength was not directly proportional to fibers length reduction due to a progressive better orientation of the fibers along the injection direction. Finally, the comparison of the mechanical results obtained with the data available for PP composites reinforced with vegetable fibers allowed to conclude that PP/basalt composites are competitive with this type of composites up to the fifth cycle, displaying a tensile modulus of 3.5 GPa and tensile strength of 38 MPa.

High Sensitivity Triboelectric Based Flexible Self-Powered Tactile Sensor with Bionic Fingerprint Ring Structure.

Flexible self-powered tactile sensors, with applications spanning wearable electronics, human-machine interaction, prosthetics, and soft robotics, offer real-time feedback on tactile interactions in diverse environments. Despite advances in their structural development, challenges persist in sensitivity and robustness, particularly when additional functionalities, such as high transparency and stretchability. In this study, we present a novel approach integrating a bionic fingerprint ring structure with a PVDF-HFP/AgNWs composite fiber electrode membrane, fabricated via 3D printing technology and electrospinning, respectively, yielding a triboelectric nanogenerator (TENG)-based self-powered tactile sensor. The sensor demonstrates high sensitivity (5.84 V/kPa in the 0-10 kPa range) and rapid response time (10 ms), attributed to the microring texture on its surface, and exhibits exceptional robustness, maintaining electrical output integrity even after 24,000 cycles of loading. These findings highlight the potential of the microring structures in addressing critical challenges in flexible sensor technology.

Innovative technology for converting automobile tire waste bead wires into recycled steel fibers for sustainable concrete composites: insights for the Al-Kharj Governorate construction industry

PurposeThe initiative for sustainability in the construction industry has led to the innovative utilization of automobile tire waste, transforming it into value-added products, toward decarbonization in the construction industry, aligning with the development and sustainability goals of Al-Kharj Governorate. However, the disposal of these materials generates significant environmental concerns. As a payoff for these efforts, this study aims to contribute to a fruitful shift toward eco-friendly recycling techniques, particularly by studying the transformation of tire waste bead wires into recycled steel tire fibers (RSTFs) for sustainable concrete composites.Design/methodology/approachThis research delves into how this technological transformation not only addresses environmental concerns but also propels sustainable tire innovation forward, presenting a promising solution for waste management and material efficiency in building materials. Recent studies have highlighted the superior tensile strength of RSTFs from discarded tires, making them suitable for various structural engineering applications. Recently, there has been a notable shift in research focus to the use of RSTFs as an alternative to traditional fibers in concrete. In this study, however, efforts have paid off in outlining a comprehensive assessment to investigate the viability and efficacy of repurposing tire bead wires into RSTFs for use in concrete composites, as reported in the literature.FindingsThis study examined the Saudi waste management, the geometrical properties of RSTFs, and their impact on the strength properties of concrete microstructure. It also examined the economic, cost, and environmental impacts of RSTFs on concrete composites, underscoring the need for the construction industry to adopt more sustainable and adaptable practices. Furthermore, the main findings of this study are proposed insights and a blueprint for the construction industry in Al-Kharj Governorate, calling for collective action from both public and private sectors, and the community to transform challenges into job opportunities for growth and sustainability.Originality/valueThis study pointed to thoroughly demonstrate the technological advancement in converting tire waste to reinforcing fibers by evaluating the effectiveness, environmental sustainability, and practicality of these fibers in eco-friendly concrete composites. Besides, the desired properties and standards for RSTFs to enhance the structural integrity of concrete composites are recommended, as is the need to establish protocols and further study into the long-term efficacy of RSTF-reinforced concrete composites.

Irradiation multi-scale damage and interface effects of 3D braided carbon fiber/epoxy composites subjected to high dose γ-rays

The serious damage caused to 3D braided carbon fiber (CF)/epoxy (EP) composites in high-energy irradiation environments is a pressing research topic that has not yet been reported. This study analyzed the γ-irradiation multi-scale damage of the matrix, interfaces, and near-interface regions in 3D braided CF/EP composites with three different braiding angles (18°, 28°, 38°) at atomic, microscopic, and macroscopic scales. The molecular structure and atomic charge information alterations of epoxy matrix were characterized using soft X-ray absorption spectroscopy (sXAS). When the irradiation dose reached 1000 KGy, the compressive strength of composites decreased by 20.88 %, 18.07 %, and 16.60 %, respectively, with an increase in the braiding angle. Micro-CT observation, along with statistical computing, confirmed that irradiation causes interface damage and increases the defect volume of 3D braided composites. Nanoindentation was used to compare the modulus of carbon fiber, interface, near-interface regions and matrix in irradiated composites and the function of CF/resin interface as an irradiation defect capture site in the irradiation resistance of resin-matrix composites has been newly established. In addition, the mechanism behind the effect of braiding angle on macroscopic properties was also analyzed.

The preparation of electrically-enhanced and hydrophilic CNTs-PVDF composite hollow fiber membranes for fouling resistance

The anaerobic membrane bioreactor has great potentials to treat the wastewater with high organic matter due to the efficient anaerobic digestion process and high biomass retention. However, the existence of membrane fouling significantly increases the maintenance cost, and always requires frequent and complex cleaning process to recover the membrane performance. Thus, it is significant to fabricate a membrane with excellent anti-fouling performance for the application in membrane bioreactors. Herein, we prepared the CNTs-PVDF hollow fiber membrane with fouling resistance via loading the conductive CNTs coating on the surface of commercial PVDF membrane by a simple cross-linking reaction with hydrophilic polyvinyl alcohol and succinic acid. “Dual defense” was constructed by the combination of the hydrophilic surface and conductive CNTs coating, which lifted the anti-fouling performance of this membrane. In the assistance of electrical effect, the permeance of the membrane with −1.2 V bias could be recovered to 95 % of original state by simple hydraulic cleaning, while that of the membrane without bias was only 58 % after filtrating the sludge of 2000 mg/L. Furthermore, this membrane also exhibited the superior stability and fouling resistance in the operation of anaerobic electrochemical membrane bioreactor, which was promising for the advanced water treatment.

Effect of heat treatment on the radial structure of coaxial polyacrylonitrile/mesophase pitch composite fiber

AbstractCoaxial composite fibers with a cortex of polyacrylonitrile (PAN) and a core layer of mesophase pitch (MP) and PAN were prepared by wet spinning, then heat‐treated in air. The effects of heat treatment on the thermal reaction characteristics, pre‐oxidation degree, radial structure, and thermal stability of coaxial composite fibers were studied by differential scanning calorometry, Raman, and thermogravimetric analysis. As the heat treatment temperature increases, the coaxial composite fibers only undergo cyclization without oxidation, the peak temperature of the thermal reaction increases from 258 to 270°C, and the enthalpy increases from 19.66 to 237.82 J g−1, the heat mainly arises from the PAN component. The Dr value of the coaxial fiber skin layer increases from 0.193 to 0.255 (330°C) and then decreases to 0.236; the core layer Dr value increases from 0.353 to 0.392 (310°C) and then decreases to 0.368. The pre‐oxidation reaction leads to an increase in sp2‐hybridized carbons and an increase in pre‐oxidation degree. When the heat treatment temperature <310°C, the pre‐oxidation degree of the composite fibers increases, leading to formation of a more stable structure compared with that at lower temperatures and an increase in the carbon residue rate.

Synthesis and photoluminescence study of two new complexes Er3+ and Yb3+ and their PMMA based composite fibers

The present article showcases the creation and evaluation of luminescent composite fibers by embedding coordination polymers, such as Er(1) {[Er(2-stp)3(H2O)]}n and Yb(2) {[Yb(2-stp)3(H2O)]}n, which are suspended in 2-sulfoterephthalate, into polymer matrices using electrospinning. The Er(1) and Yb(2) complexes were combined with poly (methyl methacrylate) (PMMA) at concentrations ranging from 5 wt.% to 25 wt.%, leading to the formation of Er@PMMA and Yb@PMMA fibers. This method resulted in one-dimensional (1D) luminescent composite fibers. Our study reveals that these composite fibers exhibit superior photoluminescence properties compared to their individual pure complex counterparts. This enhancement is ascribed to the synergistic effects of the PMMA matrix and electrospun fiber structure. Furthermore, we observed that the composite nanofibers exhibited significantly better thermal and photostability compared to their pure complexes.

Simulation of polymer solution slip motion and composite fiber fabrication in rotary jet spinning

Composite nanofibers are widely used as a novel nanomaterial in various fields, and the key technologies of preparation methods and equipment optimization have become the focus of research. Rotary jet spinning uses the centrifugal force generated by high-speed rotation to produce slip motion of two polymer solutions in the nozzle, and as the slip velocity increases, a rotating jet is eventually formed at the nozzle to eject the composite nanofibers. The slip motion of the polymer solution is one of the important factors affecting the rotating jet composite spinning, which directly affects the velocity distribution and flow stability of the polymer solution, and ultimately affects the morphology and quality of the composite nanofibers. By simulating the flow process of polymer solution inside the nozzle, the effect of slip motion on the flow of polymer solution is verified, which further illustrates that the rotational speed has the greatest influence on the preparation of composite nanofibers. Finally, PEO/PVA composite nanofibers were successfully prepared and collected by using a rotary jet spinning device in the range of 1500–3000 rpm, and the morphology and quality of the fibers were characterized and analyzed by scanning electron microscopy (SEM), which provided experimental bases for the simulation of the slip motion of the polymer solution and the study of composite fiber preparation.

Application of multi-layered composite fiber films with enhanced piezoelectric performance in flexible energy harvesting devices

Flexible electronic components such as wearable sensors, energy harvesting devices, and human health monitoring systems based on piezoelectric materials have garnered significant attention within the scientific community. In this study, PZT nanofibers were modified with dopamine hydrochloride prior to their integration into PVDF fibers, serving as piezoelectric reinforcements to enhance the mechanical and piezoelectric characteristics of composite fiber films. Subsequently, a facile hot-pressing method was employed to fabricate multilayered films characterized by a densely packed surface fiber arrangement and a loosely organized internal fiber orientation, which markedly improved the self-supporting ability and fiber density of the electrospun fiber films. A detailed investigation into the micro-morphology, crystallinity, and enhanced piezoelectric properties of the films was conducted. Notably, the composite fiber film containing 6 wt% PZT NFs exhibited a peak piezoelectric coefficient (d33) of 29 pC/N, resulting in an output voltage of 13.8 V. This represents a 2.23-fold enhancement in d33 value and a 4.6-fold increase in output voltage when compared to the pristine PVDF fiber film, which had a d33 of 13 pC/N and an output voltage of 3 V. The power density achieved by the sensor is 0.73 μW/cm2. This performance is underpinned by a high piezoelectric coefficient, outstanding output characteristics, and robust stability, which collectively enhance the sensor's efficacy in various applications. This research presents an effective approach for augmenting the piezoelectric performance of PVDF-based composite films and paves the way for the advancement of piezoelectric energy harvesting applications.

Capillarity-assisted assembly of composite fibers to enable highly conductive fabrics for electromagnetic interference shielding

Poor adhesion between silver nanomaterials and substrates seriously restricts the development of electronic composite devices. In this work, flexible and conductive silver nanowires/fibroin/degummed silk (AgNWs/fibroin/dSF) composite fibers with high adhesion and conductivity via capillarity-assisted assembly for electromagnetic interference (EMI) shielding are designed and fabricated by a facile and scalable all-solution dip-coating method. The nanocomposite fiber possesses high conductivity with a resistance of 8.8 Ω/cm at a low AgNWs/fibroin loading of 19.3 wt%. The assistance of the capillary force in the fiber highly increases the mass of deposited AgNWs. Furthermore, the AgNWs show high adhesion on the fibers in the tape-peel test. The enhanced deposition factors and mechanisms are detailly investigated. Moreover, the composite fibers are further woven into a soft and flexible fabric. The composite fabric shows an absorption-dominated EMI shielding performance with an efficient shielding effectiveness of 38 dB. The capillarity-assisted assembly is an attractive procedure for constructing high-conductive and uniform coatings for a wide application.

Engineering robust porous/dense composite hollow fiber membranes for highly efficient hydrogen separation

BaZr0.7Ce0.2Y0.1O3-δ (BZCY), a perovskite-type mixed protonic and electronic conducting oxide, holds significant potential for H2 separation and purification as a membrane. The introduction of a porous modification layer as an exchange-active component offers a potential solution to enhance H2 permeability. However, achieving the desired porous/dense structure presents a notable challenge for practical implementation. In this study, various methods were developed to address sintering kinetics, encompassing both chemical aspects (e.g., interlayer reactions) and physical factors (e.g., thermal expansion), for fabricating a porous BZCY modification layer on a 4-channel BZCY hollow fiber membrane. The optimal composite hollow fiber membrane, resulting from a combination of readily sintered hollow fiber and powders for constructing the porous layers, exhibits an exceptional H2 permeation flux of 0.48 mL min−1 cm−2 at 900 °C using 50 % H2/N2 as the feed gas, which represents a threefold increase compared to the performance of the bare BZCY membrane. The H2 permeation flux stabilized at 0.52 mL min−1 cm−2 for 500 h under water vapor conditions. These findings enabled us to identify the most effective approach, unlocking the full potential of surface-modified hollow fiber membranes and advancing their capabilities in H2 permeation applications.

Torsion and Combined Torsion-Axial Load Behaviour of Concrete Filled Steel Tube Columns with and without ECC/CFRP Wrap

ABSTRACT Concrete-filled tube columns may experience coupled torsion and axial compression under seismic and wind loading. Fifteen square, rectangular, and circular concrete filled steel/aluminium tube (CFST/CFAT) are tested under pure torsion to understand the behaviour and develop/validate finite element (FE) models. Parametric studies under pure torsion are conducted using FE models to study the effect of geometric (tube cross-section, length, and thickness) and tube/concrete material parameters on torsional strength, stiffness, and tube-concrete composite interaction. FE models are used to study strength, stiffness, and failure modes of CFST columns under combined torsion and axial compression load at various preload levels of axial and torsion. Coupled torsional preloading and subsequent axial load reduce the axial load capacity significantly, while coupled axial preloading and subsequent torsional loading have shown no significant influence on the torsional strength of CFST columns. Implementation of FE models developed for CFST columns with engineered cementitious composite (ECC) and carbon fibre reinforced polymer (CFRP) wraps showed significant enhancement of axial strength and stiffness compared to control (without wrap) even under high torsional preload level. The energy absorption capacity and ductility of the CFRP wrapped CFST column are about 1.38 and 1.1 times higher than its counterpart with ECC wrap of same axial load capacity. Overall, the results suggest that use of both CFRP and ECC wrap is an effective approach to enhance the torsional behaviour and ductility of CFST columns under combined torsion and axial loading conditions. However, high crack resistance and better post-peak ductility of ECC wrapped CFST compared to sudden CFRP rupture failure in CFRP-wrapped counterpart should be taken into consideration for seismic applications.

Facile Fabrication of SrTiO3/In2O3 on Carbon Fibers via a Self-Assembly Strategy for Enhanced Photocatalytic Hydrogen Production

Photocatalytic water splitting by semiconductors is considered a promising and cost-effective method for achieving sustainable hydrogen production. In this study, a CF/SrTiO3/In2O3 photocatalytic material with a double-layer core–shell structure was developed. The experimental results indicated that the produced CF/SrTiO3/In2O3 composite fiber displayed superior photocatalytic hydrogen production performance, achieving a hydrogen evolution rate of approximately 320.71 μmol/g·h, which is roughly seven times higher than that of the CF/SrTiO3 fiber alone. The enhanced photocatalytic activity of the CF/SrTiO3/In2O3 fiber can be attributed to the heterojunction structure enriched with oxygen vacancies. It was found that these oxygen vacancies created defective states that served as traps for photogenerated electrons, facilitating their migration to the surface defect states and enabling the reduction of H+ in water to produce hydrogen. Furthermore, the synergy between the heterojunction structure and the conductivity of the carbon fiber promoted the generation and migration of photogenerated electrons, reduced the recombination of photogenerated electron–hole pairs, and ultimately improved photocatalytic hydrogen production. This study presents a new approach for designing efficient photocatalysts with surface oxygen vacancies on carbon fibers, providing new insights into the sustainable application of photocatalysts.

Investigating the role of steel and polypropylene fibers for enhancing mechanical properties and microstructural performance in mitigating conversion effects in calcium aluminate cement

Fiber reinforcement is widely employed in numerous industries due to its exceptional mechanical properties; however, its specific role in enhancing the strength of calcium aluminate cement (CAC) composites remains inadequately understood. This study investigates the influence of fiber addition on the mechanical characteristics of CAC composites during curing. Two types of fibers, steel and polypropylene, were incorporated into CAC composites, and their mechanical properties, chemical composition, and microstructural performance were evaluated using various methods. Assessments including flowability, bulk density, volume of permeable voids, water absorption, and mechanical strength tests were conducted, alongside X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), and Field Emission Scanning Electron Microscopy (FESEM) analysis. Results reveal a significant enhancement in mechanical strengths with the inclusion of fibers in CAC composites. The addition of 1% fibers to the composites resulted in significant improvements. Steel fibers (SF) led to notable enhancements of approximately 19.7%, 68%, and 26.4% in compressive, direct tensile, and flexural strengths, respectively, while polypropylene fibers (PF) resulted in enhancements of 1.9%, 20%, and 16.7%, respectively. Microstructural analysis revealed that SF and PF contribute to pore refinement, enhancing strength and durability. Findings suggest that SF addition effectively mitigates strength loss induced by the conversion effects of stable phase C3AH6 in CAC, thereby fostering the development of an environmentally friendly, quick-setting, high-performance concrete system. This research offers valuable insights for the design and potential enhancement of CAC-based composites to improve performance and durability under severe conditions.

Experimental analysis of 3D printed continuous carbon/glass hybrid fiber reinforced PLA composites: Revealing synergistic mechanical properties and failure mechanisms

AbstractThis study investigates the mechanical properties of continuous carbon/glass hybrid fiber‐reinforced polylactic acid (PLA) composites (HFRC) produced through the three dimensions (3D) printing process, comparing them with single carbon fiber‐reinforced PLA composites (CFRC). Initially, composite prepreg filaments are prepared using an impregnation device, followed by fabrication using a 3D printer. The mechanical performance results reveal a 13% increase in tensile strength for HFRC compared with CFRC. Due to differing elongation rates of carbon and glass fibers, HFRC exhibits two strength peaks, while CFRC demonstrates a 37% higher bending strength than HFRC. Scanning electron microscope images indicate that the tensile failure mechanism involves fiber brittle fracture and fiber‐matrix interface debonding, while the bending failure mechanism includes fiber pullout, fiber debonding, fiber cluster buckling, and interlayer interface failure.Highlights To realize the moldless rapid manufacturing of continuous hybrid fiber‐reinforced PLA composites. The stress–strain curves of single fiber‐reinforced composites and hybrid fiber‐reinforced composites are obviously different. Elucidating the effect of single fiber/hybrid fiber in composites on mechanical properties and failure mechanism according to micro‐morphology.

Wet Spun Composite Fiber with an Ordered Arrangement of PEDOT:PSS‐Coated Te Nanowires for High‐Performance Wearable Thermoelectric Generator

AbstractThermoelectric (TE) fibers are more suitable than films for portable or wearable devices. Herein, 2–3 nm thick poly (3,4‐ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) layer‐coated tellurium nanowires (PC‐Te NWs) are in situ prepared by a hydrothermal method. Then a series of PEDOT: PSS/PC‐Te NWs composite fibers are prepared by wet spinning and post‐treatment. The nanolayer prevents the agglomeration of the Te NWs and makes the NWs and PEDOT:PSS matrix have good compatibility, which results in the PC‐Te NWs content to a high value of 70 wt% and the fibers still with flexibility. The high aspect ratio of the PC‐Te NWs and the stress from the inner wall of the needle during spinning make the NWs ordered align along the composite fiber. Due to the large content and orientational arrangement of the PC‐Te NWs, as well as effective post‐treatment, an optimized composite fiber shows a power factor of 385.4 µW m−1 K−2 at 300 K, which is ≈4.9 times as high as the highest value of previously reported PEDOT:PSS/Te NWs‐based composite fibers. In addition, the composite fiber has good flexibility. The flexible TE generators assembled have excellent output performance. This work provides an effective strategy for the preparation of high‐performance flexible TE composite fibers.

Functionalized-MXene-based imprinted MOFs composite membranes for the selective separation of ribavirin

The evident decrease for membrane-treated performance in response to multi-component mixture greatly limited its application. Here, we prepared blended nanomolecularly imprinted composite fiber membranes (CXPM-MIMs) with in situ growth of imprinted MOFs on carboxyl functionalized MXene. Through the carboxylate-assisted coordination pathway, a chelation site is provided by the carboxylate-modified MXene to coordinate with NH2-UiO-66, creating a tightly linked NH2-UiO-66/carboxylate-functionalized MXene heterostructure. The key role of the modified carboxyl group can be identified so that it can help to create a strong coordination bond between the two materials. Conventional MOFs typically lack selectivity and specificity. Here, we present a molecularly imprinted nanocomposite MOFs membrane material that exhibits selective adsorption and molecular separation capabilities. Imprinted UiO-66 (Ce) based on diamino-terephthalic acid was synthesized with water as the only solvent without adding any regulator or additive. By adding ribavirin molecules to multicomponent MOFs using a molecular imprinting technique and carrying out adsorption tests (isothermal and kinetic) as well as selectivity testing, we were able to demonstrate this adsorption-separation mechanism. The valuable testing outcomes shown that the as-prepared CXPM-MIMs performed excellently in terms of pemselectivity for ribavirin (RBV) (permselectivity factor β = 4.89, 10.14, 9.23) in addition to exhibiting perfect specific adsorption ability (58.3 mg g−1). The strong permselectivity and particular identification capacity of CXPM-MIMs demonstrated their tremendous potential in the treatment of RBV contamination.

Simultaneous measurement of thermal conductivity and emissivity of micro/nanomaterials

Although thermal conductivity of micro/nano scale material has been readily measured, the high specific surface area leads to non-negligible radiative heat transfer. Here, a method for simultaneous measurement of intrinsic thermal conductivity and emissivity of micro/nano materials was developed and verified. The physical model of this measurement principle consisted of two parallel platinum wires, which serve as both heaters and heat flux meters. Thermal conductivity and emissivity can be derived by comparing the changes in the average temperature rise of the heater and sensor platinum wires before and after attaching the test sample. The thermal conductivity and emissivity of an individual platinum wire were determined to 71.7 W/(m·K) and 0.14, which are consistent with the reference values. Subsequently, the thermal conductivity and emissivity of the polymer composite fiber were measured to be 1.45 W/(m·K), 0.73 and 1.87 W/(m·K), 0.8 at different composite filler concentrations. In principle, this method is applicable for accurately measuring the thermal transport properties of any micro/nano wires using appropriate sensors.

Wet-spinning of reduced graphene oxide composite fiber by mechanical synergistic effect with graphene scrolling method

Carbon-based fibers have attracted attention in various field owing to their exceptional properties, including high tensile strength, thermal stability, and electrical conductivity. In particular, graphene-based high-strength fibers are promising materials in aerospace, automotive, and marine sectors. Recently, the hybrid fiber, consisting of carbon nanotubes (CNTs) and graphene with enhanced toughness was reported by deflecting cracks and enabling high deformation. However, complex synthesis and structural optimization of composite fiber with two different materials make challenge for mass production. Here, we introduce a novel graphene composite fiber, consisting of reduced graphene oxide (rGO) and scrolled rGO (SrGO), showing remarkable toughness. A multidimensional-state solution with 2D rGO and 1D SrGO was obtained by using a simple sonication technique. Mass production of high-toughness composite fibers was achieved via wet-spinning, with enhanced toughness attributed to microstructure optimization by controlling the SrGO ratio. Additionally, the use of poly(vinyl alcohol) (PVA) as the matrix facilitated high deformation, resulting in a remarkable 90.7 % increase in mechanical toughness without complex composite material synthesis.

In Situ Photoactivated Antibacterial and Antioxidant Composite Materials to Promote Bone Repair.

Trauma and tumor removal usually cause bone defects; in addition, the related postoperative infection also shall be carefully considered clinically. In this study, polylactic acid (PLLA) composite fibers containing Cerium oxide (CeO2) are first prepared by electrospinning technology. Then, the PLLA/CeO2@PDA/Ag composite materials are successfully prepared by reducing silver ion (Ag+) to nano-silver (AgNPs) coating in situ and binding AgNPs to the materials surface by mussel structure liked polydopamine (PDA). In the materials, Ag+ can be slowly released in simulated body fluids. Based on the photothermal performance of AgNPs, the photothermal conversion efficiency of the materials is 21%, under NIR 808nm illumination. The effective photothermal conversion can help materials fighting with E. coli and S. aureus in 3 h, with an antibacterial rate of 100%. Additionally, the sustained Ag+ release contributes to the antibacterial in long term. Meanwhile, the materials can mimic the bio-behavior of superoxide dismutase and catalase in decreasing the singlet oxygen level and removing the excess reactive oxygen species. Furthermore, the materials are beneficial for cell proliferation and osteogenic differentiation in vitro. In this study, a promising bone-regenerated material with high photothermal conversion efficiency and antibacterial and anti-oxidation properties, is successfully constructed.