Pub Date : 2024-10-09DOI: 10.1016/j.mtnano.2024.100529
Nuohua Xie , Wenzi Chen , Ya Ning, Xiaojun Zeng
Developing high-performance materials with ultra-high reflection loss (RL ≤ −65 dB) for electromagnetic wave (EMW) absorption is pivotal to address electromagnetic pollution, but it is still challenging. Herein, a two-dimensional (2D)/2D PFL g-C3N4/NiCo2O4 heterostructure with porous few-layer g-C3N4 (PFL g-C3N4) and ultrathin NiCo2O4 nanosheets has been prepared by self-assembly, hydrothermal reaction, and calcination strategies. The 2D/2D heterostructure exhibits extraordinary EMW absorption property, achieving a reflection loss (RL) value of −68.59 dB and an effective absorption bandwidth (EAB) of 1.92 GHz at a matching thickness of 2.5 mm. As expected, the porous few layer g-C3N4 nanosheets provide rich interface which increases multiple reflection paths and enhances the conduction loss. The cooperative effects of magnetic loss, dielectric loss, and impedance matching contribute to the exceptional EMW absorption property of PFL g-C3N4/NiCo2O4 (2D/2D) heterostructure. The potential of PFL g-C3N4/NiCo2O4 in actual radar stealth is verified through radar scattering cross-section (RCS) simulation. This work paves the way for utilizing 2D/2D heterostructure as an ultra-efficient EMW absorbers.
{"title":"Construction of 2D/2D heterostructure with porous few layer g-C3N4 and NiCo2O4 nanosheets towards electromagnetic wave absorption","authors":"Nuohua Xie , Wenzi Chen , Ya Ning, Xiaojun Zeng","doi":"10.1016/j.mtnano.2024.100529","DOIUrl":"10.1016/j.mtnano.2024.100529","url":null,"abstract":"<div><div>Developing high-performance materials with ultra-high reflection loss (<em>R</em><sub>L</sub> ≤ −65 dB) for electromagnetic wave (EMW) absorption is pivotal to address electromagnetic pollution, but it is still challenging. Herein, a two-dimensional (2D)/2D PFL g-C<sub>3</sub>N<sub>4</sub>/NiCo<sub>2</sub>O<sub>4</sub> heterostructure with porous few-layer g-C<sub>3</sub>N<sub>4</sub> (PFL g-C<sub>3</sub>N<sub>4</sub>) and ultrathin NiCo<sub>2</sub>O<sub>4</sub> nanosheets has been prepared by self-assembly, hydrothermal reaction, and calcination strategies. The 2D/2D heterostructure exhibits extraordinary EMW absorption property, achieving a reflection loss (<em>R</em><sub>L</sub>) value of −68.59 dB and an effective absorption bandwidth (EAB) of 1.92 GHz at a matching thickness of 2.5 mm. As expected, the porous few layer g-C<sub>3</sub>N<sub>4</sub> nanosheets provide rich interface which increases multiple reflection paths and enhances the conduction loss. The cooperative effects of magnetic loss, dielectric loss, and impedance matching contribute to the exceptional EMW absorption property of PFL g-C<sub>3</sub>N<sub>4</sub>/NiCo<sub>2</sub>O<sub>4</sub> (2D/2D) heterostructure. The potential of PFL g-C<sub>3</sub>N<sub>4</sub>/NiCo<sub>2</sub>O<sub>4</sub> in actual radar stealth is verified through radar scattering cross-section (RCS) simulation. This work paves the way for utilizing 2D/2D heterostructure as an ultra-efficient EMW absorbers.</div></div>","PeriodicalId":48517,"journal":{"name":"Materials Today Nano","volume":"28 ","pages":"Article 100529"},"PeriodicalIF":8.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.mtnano.2024.100525
Chuhao Yao , Xiaomeng Zhang , Cheng Lu , Yu Liu , Hailiang Li , Changqing Xie
Owing to its excellent localized surface plasmon resonance (LSPR) effect, noble metal nanoparticles (NPs) find extensive application in the preparation of surface-enhanced Raman scattering (SERS) substrates. However, due to process limitations, the practicality and testing effectiveness of SERS substrates still leaves much to be desired. Here, a wafer-scale gold (Au) NPs silicon (Si) micro/nano-hybrid structured substrate is prepared. This is achieved through two-step etching, followed by decorating Au-NPs onto the structure via self-assembly process induced by de-wetting. Finite-difference time-domain (FDTD) simulations reveal that the significant enhancement of local electric field in the voids between Au-NPs and Si is crucial for enhancing SERS. Using Rhodamine 6G (R6G) as the probe molecule, performance of the fabricated SERS substrate is investigated. It demonstrates a minimum detection limit of 10−11 M, with a calculated enhancement factor of 4.40 × 108, indicating its high sensitivity. The minimum relative standard deviation for the substrate is 5.254 %. After 20 days of placement, the SERS performance show tiny variation. Even after four cycles of cleaning experiments, it still maintains outstanding SERS performance. This demonstrates its excellent stability, uniformity and reusability. Our research provides guidance for the efficient and low-cost fabrication of high-performance SERS substrates.
{"title":"High-performance SERS substrate based on gold nanoparticles-decorated micro/nano-hybrid hierarchical structure","authors":"Chuhao Yao , Xiaomeng Zhang , Cheng Lu , Yu Liu , Hailiang Li , Changqing Xie","doi":"10.1016/j.mtnano.2024.100525","DOIUrl":"10.1016/j.mtnano.2024.100525","url":null,"abstract":"<div><div>Owing to its excellent localized surface plasmon resonance (LSPR) effect, noble metal nanoparticles (NPs) find extensive application in the preparation of surface-enhanced Raman scattering (SERS) substrates. However, due to process limitations, the practicality and testing effectiveness of SERS substrates still leaves much to be desired. Here, a wafer-scale gold (Au) NPs silicon (Si) micro/nano-hybrid structured substrate is prepared. This is achieved through two-step etching, followed by decorating Au-NPs onto the structure via self-assembly process induced by de-wetting. Finite-difference time-domain (FDTD) simulations reveal that the significant enhancement of local electric field in the voids between Au-NPs and Si is crucial for enhancing SERS. Using Rhodamine 6G (R6G) as the probe molecule, performance of the fabricated SERS substrate is investigated. It demonstrates a minimum detection limit of 10<sup>−11</sup> M, with a calculated enhancement factor of 4.40 × 10<sup>8</sup>, indicating its high sensitivity. The minimum relative standard deviation for the substrate is 5.254 %. After 20 days of placement, the SERS performance show tiny variation. Even after four cycles of cleaning experiments, it still maintains outstanding SERS performance. This demonstrates its excellent stability, uniformity and reusability. Our research provides guidance for the efficient and low-cost fabrication of high-performance SERS substrates.</div></div>","PeriodicalId":48517,"journal":{"name":"Materials Today Nano","volume":"28 ","pages":"Article 100525"},"PeriodicalIF":8.2,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-03DOI: 10.1016/j.mtnano.2024.100526
Irene Solana , María Dolores Ynsa , Fátima Cabello , Fernando Chacon-Sanchez , Jan Siegel , Mario Garcia-Lechuga
The manipulation of the optical properties of plasmonic nanocomposites is of high interest for the development of advanced optical devices with tailored unique properties. Achieving these objectives requires a combination of synthesis techniques and post-fabrication strategies. Here, we combine the use of two well-established physical strategies: MeV ion implantation and femtosecond laser processing. Firstly, we synthesize Au-doped soda lime glass nanocomposite through ion beam implantation (Au2+ at 1.8 MeV) followed by thermal annealing. This synthesis procedure results in a peculiar optical response based on the combination of Au-nanoparticle plasmonic resonance and a Fabry-Perot interference, caused by the deep implantation (centered at 480 nm). Secondly, this dual response is demonstrated to be highly tuneable by non-resonant femtosecond laser irradiation (800-nm wavelength and 130-fs pulse duration). Depending on the laser fluence, three transformation regimes are distinguished: supressing the interferometric response by spallative ablation, inducing vivid blue colors by surface swelling, and producing red-shifted color changes by multi-shot irradiation at low fluences. The proposed method is very versatile, since it is applicable to any dielectric matrix or implanted element. This work paves the way to a new route for the development of scalable and tuneable nanocomposites with several potential applications in optics.
{"title":"Optoplasmonic tuneable response by femtosecond laser irradiation of glass with deep-implanted gold nanoparticles","authors":"Irene Solana , María Dolores Ynsa , Fátima Cabello , Fernando Chacon-Sanchez , Jan Siegel , Mario Garcia-Lechuga","doi":"10.1016/j.mtnano.2024.100526","DOIUrl":"10.1016/j.mtnano.2024.100526","url":null,"abstract":"<div><div>The manipulation of the optical properties of plasmonic nanocomposites is of high interest for the development of advanced optical devices with tailored unique properties. Achieving these objectives requires a combination of synthesis techniques and post-fabrication strategies. Here, we combine the use of two well-established physical strategies: MeV ion implantation and femtosecond laser processing. Firstly, we synthesize Au-doped soda lime glass nanocomposite through ion beam implantation (Au<sup>2+</sup> at 1.8 MeV) followed by thermal annealing. This synthesis procedure results in a peculiar optical response based on the combination of Au-nanoparticle plasmonic resonance and a Fabry-Perot interference, caused by the deep implantation (centered at 480 nm). Secondly, this dual response is demonstrated to be highly tuneable by non-resonant femtosecond laser irradiation (800-nm wavelength and 130-fs pulse duration). Depending on the laser fluence, three transformation regimes are distinguished: supressing the interferometric response by spallative ablation, inducing vivid blue colors by surface swelling, and producing red-shifted color changes by multi-shot irradiation at low fluences. The proposed method is very versatile, since it is applicable to any dielectric matrix or implanted element. This work paves the way to a new route for the development of scalable and tuneable nanocomposites with several potential applications in optics.</div></div>","PeriodicalId":48517,"journal":{"name":"Materials Today Nano","volume":"28 ","pages":"Article 100526"},"PeriodicalIF":8.2,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.mtnano.2024.100524
Caio Machado Fernandes , João Paulo C. Moura , Aline B. Trench , Odivaldo C. Alves , Yutao Xing , Marcos R.V. Lanza , Júlio César M. Silva , Mauro C. Santos
The current study illustrates the successful synthesis of Ce1.0Mn0.9Co0.1 nanoparticles, characterized through XRD, EPR, magnetization curves, and TEM/HRTEM/EDX analyses. These nanoparticles were then loaded into the carbon Vulcan XC72 and the carbon Printex L6 matrices in varying amounts (1, 3, 5, and 10 % w/w) via wet impregnation method to fabricate electrocatalysts for the 2-electron ORR. Before experimentation, the material was characterized via XPS and contact angle measurements. The electrochemical results produced significant findings, indicating that the electrocatalysts with the nanostructures modifying both carbon blacks notably augmented currents in rotating ring-disk electrode measurements, signifying enhanced selectivity for H2O2 production. Moreover, our research underscored the significant impact of Magnetic Field-Enhanced Electrochemistry, employing a constant magnetic field strength of 2000 Oe, on 2-electron ORR experiments. Particularly noteworthy were the observed results surpassing the ones without the magnetic field, demonstrating heightened currents and improved selectivity for H2O2 production (more than 90 %) facilitated by CeMnCo nanoparticles. These significant findings in electrocatalytic efficiency have practical implications, suggesting the potential for developing more efficient and selective catalysts for the 2-electron ORR.
{"title":"Magnetic field-enhanced two-electron oxygen reduction reaction using CeMnCo nanoparticles supported on different carbonaceous matrices","authors":"Caio Machado Fernandes , João Paulo C. Moura , Aline B. Trench , Odivaldo C. Alves , Yutao Xing , Marcos R.V. Lanza , Júlio César M. Silva , Mauro C. Santos","doi":"10.1016/j.mtnano.2024.100524","DOIUrl":"10.1016/j.mtnano.2024.100524","url":null,"abstract":"<div><div>The current study illustrates the successful synthesis of Ce<sub>1.0</sub>Mn<sub>0.9</sub>Co<sub>0.1</sub> nanoparticles, characterized through XRD, EPR, magnetization curves, and TEM/HRTEM/EDX analyses. These nanoparticles were then loaded into the carbon Vulcan XC72 and the carbon Printex L6 matrices in varying amounts (1, 3, 5, and 10 % w/w) via wet impregnation method to fabricate electrocatalysts for the 2-electron ORR. Before experimentation, the material was characterized via XPS and contact angle measurements. The electrochemical results produced significant findings, indicating that the electrocatalysts with the nanostructures modifying both carbon blacks notably augmented currents in rotating ring-disk electrode measurements, signifying enhanced selectivity for H<sub>2</sub>O<sub>2</sub> production. Moreover, our research underscored the significant impact of Magnetic Field-Enhanced Electrochemistry, employing a constant magnetic field strength of 2000 Oe, on 2-electron ORR experiments. Particularly noteworthy were the observed results surpassing the ones without the magnetic field, demonstrating heightened currents and improved selectivity for H<sub>2</sub>O<sub>2</sub> production (more than 90 %) facilitated by CeMnCo nanoparticles. These significant findings in electrocatalytic efficiency have practical implications, suggesting the potential for developing more efficient and selective catalysts for the 2-electron ORR.</div></div>","PeriodicalId":48517,"journal":{"name":"Materials Today Nano","volume":"28 ","pages":"Article 100524"},"PeriodicalIF":8.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-29DOI: 10.1016/j.mtnano.2024.100522
S. Zhan , X.M. Xiang , Y.X. Lai , X.J. Hu , Z.B. He , J.H. Chen
Since the discovery of quasicrystals, their applications to industry have been interesting issues, among which attempts of introducing quasicrystal-related precipitates into the Al-matrix to enhance properties of Al alloys have been made without adequate understandings. Here, we report a formation pathway of quasicrystal-related precipitates in the Al-matrix of an AlEr(Fe) alloy. It is shown that upon thermal aging of the alloy, Al3Er precipitates form firstly in the Al-matrix, then quasicrystal-related (AlFe)-precipitates may nucleate heterogeneously within the Al3Er precipitates and grow large. As the quasicrystal-related precipitate grows large, the Al3Er-precipitate reform as the thin “skin” of the formed composite precipitate, keeping the quasicrystal-related portion well separated from the matrix. Atomic-resolution electron microscopy and spectroscopy reveal that these composite precipitates are the mixtures of the Al13Fe4 quasicrystal approximant structure and/or quasicrystal-related aperiodic structures, as well as their surrounding skin with Al3Er-structure. As such, Fe atoms as vexing impurity in Al alloys can be absorbed continuously into such composite precipitates. Our findings provide insights into the feasibility to form quasicrystal-related precipitates in the Al-matrix.
{"title":"Nucleation and growth of quasicrystal-related precipitates within the Al-matrix of AlEr(Fe) alloys","authors":"S. Zhan , X.M. Xiang , Y.X. Lai , X.J. Hu , Z.B. He , J.H. Chen","doi":"10.1016/j.mtnano.2024.100522","DOIUrl":"10.1016/j.mtnano.2024.100522","url":null,"abstract":"<div><div>Since the discovery of quasicrystals, their applications to industry have been interesting issues, among which attempts of introducing quasicrystal-related precipitates into the Al-matrix to enhance properties of Al alloys have been made without adequate understandings. Here, we report a formation pathway of quasicrystal-related precipitates in the Al-matrix of an AlEr(Fe) alloy. It is shown that upon thermal aging of the alloy, Al<sub>3</sub>Er precipitates form firstly in the Al-matrix, then quasicrystal-related (AlFe)-precipitates may nucleate heterogeneously within the Al<sub>3</sub>Er precipitates and grow large. As the quasicrystal-related precipitate grows large, the Al<sub>3</sub>Er-precipitate reform as the thin “skin” of the formed composite precipitate, keeping the quasicrystal-related portion well separated from the matrix. Atomic-resolution electron microscopy and spectroscopy reveal that these composite precipitates are the mixtures of the Al<sub>13</sub>Fe<sub>4</sub> quasicrystal approximant structure and/or quasicrystal-related aperiodic structures, as well as their surrounding skin with Al<sub>3</sub>Er-structure. As such, Fe atoms as vexing impurity in Al alloys can be absorbed continuously into such composite precipitates. Our findings provide insights into the feasibility to form quasicrystal-related precipitates in the Al-matrix.</div></div>","PeriodicalId":48517,"journal":{"name":"Materials Today Nano","volume":"28 ","pages":"Article 100522"},"PeriodicalIF":8.2,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Assessing electromagnetic constitutive parameters is crucial to prescribe the macroscopic properties of composites and their prospective applications. Free space methods are widely used for this purpose, due to their nondestructive/noncontact nature and their applicability on composites incorporating large inclusions or over-frequency bands where waveguide measurements are impractical. However, there still exists issues associated with automation, accurate calibration, remote controlling, and multifunctional characterization. Here, we designed and implemented a microwave-integrated laboratory including a test bench for permittivity/permeability and impedance measurements of individual inclusions and a free space setup for transmission/reflection measurements of fiber-based composites. Easy switching between the bench and antenna measurements was enabled by a homemade RF multiplexer. A three-stage calibration was applied: 2-port error correction (12-term model) of the vector network analyzer and the cables connecting it to the multiplexer, de-embedding of the cables connecting the multiplexer to the switches within the antenna pillars, and thru, reflect, and line (TRL) error correction for the antennas and free space. Exploiting robotics for precise antenna movement and TRL calibration enabled adjustment of the antenna distance to the test frame to a maximum of 2.5 m with a 100 μm accuracy. A multifunctional frame for external stimuli application was also designed. Apart from automation, remote control was realized through user-friendly graphical interfaces and remote access software allowing to swiftly respond to challenges faced during the global pandemic. The free space setup effectiveness was then validated by measuring the transmission/reflection of microwire-based composites from 0.5 to 20 GHz under various magnetic fields.
{"title":"Design and validation of an automated and remote free space measurement system for nondestructive testing of fiber composites","authors":"Azim Uddin , Diana Estevez , Hua-Xin Peng , Faxiang Qin","doi":"10.1016/j.mtnano.2024.100521","DOIUrl":"10.1016/j.mtnano.2024.100521","url":null,"abstract":"<div><div>Assessing electromagnetic constitutive parameters is crucial to prescribe the macroscopic properties of composites and their prospective applications. Free space methods are widely used for this purpose, due to their nondestructive/noncontact nature and their applicability on composites incorporating large inclusions or over-frequency bands where waveguide measurements are impractical. However, there still exists issues associated with automation, accurate calibration, remote controlling, and multifunctional characterization. Here, we designed and implemented a microwave-integrated laboratory including a test bench for permittivity/permeability and impedance measurements of individual inclusions and a free space setup for transmission/reflection measurements of fiber-based composites. Easy switching between the bench and antenna measurements was enabled by a homemade RF multiplexer. A three-stage calibration was applied: 2-port error correction (12-term model) of the vector network analyzer and the cables connecting it to the multiplexer, de-embedding of the cables connecting the multiplexer to the switches within the antenna pillars, and thru, reflect, and line (TRL) error correction for the antennas and free space. Exploiting robotics for precise antenna movement and TRL calibration enabled adjustment of the antenna distance to the test frame to a maximum of 2.5 m with a 100 μm accuracy. A multifunctional frame for external stimuli application was also designed. Apart from automation, remote control was realized through user-friendly graphical interfaces and remote access software allowing to swiftly respond to challenges faced during the global pandemic. The free space setup effectiveness was then validated by measuring the transmission/reflection of microwire-based composites from 0.5 to 20 GHz under various magnetic fields.</div></div>","PeriodicalId":48517,"journal":{"name":"Materials Today Nano","volume":"28 ","pages":"Article 100521"},"PeriodicalIF":8.2,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-28DOI: 10.1016/j.mtnano.2024.100520
Dan Wu , Di Lan , Shijie Zhang , Qinchuan He , Xiping Zhou , Yiqun Wang
In order to solve the problem of impedance mismatch of carbon fiber absorbing materials, it is crucial to create a carbon-based absorbing material with a special structure, synergistic magnetic and dielectric properties. In this paper, necklace-shaped Co@N-doped carbon polyhedron/carbon nanofiber (Co@NCP/CNF) composites with synergistic magnetic and dielectric properties are successfully fabricated by electrospinning. Compared with Co@NCP and CNF, the optimal minimum reflection loss of Co@NCP/CNF composite is −66.14 dB at 2.89 mm and the maximum effective absorption bandwidth is 6.24 GHz (11.76–18.00 GHz) at 2.25 mm at a low filler load of 10 wt%. The necklace-like structure, the coupling effect of dielectric and magnetic materials and the heterogeneous interface form multiple polarizations, conductive losses and multiple loss mechanisms to optimize impedance matching and attenuation performance, which is conducive to excellent absorption performance. More importantly, the radar cross section (RCS) reduction is as high as 24.02 dB m2, which has proven to have a good absorption effect in actual application environments. This work combines the advantages of Co@NCP and CNF very well, which provides guidance for designing EM waves nanocomposite fiber absorbers with lightweight and strong absorbing properties.
为了解决碳纤维吸波材料的阻抗失配问题，创造一种具有特殊结构、协同磁性和介电特性的碳基吸波材料至关重要。本文利用电纺丝技术成功制备了具有协同磁性和介电特性的项链形 Co@N 掺杂碳多面体/碳纳米纤维（Co@NCP/CNF）复合材料。与 Co@NCP 和 CNF 相比，Co@NCP/CNF 复合材料在 2.89 mm 时的最佳最小反射损耗为 -66.14 dB，在 10 wt%的低填充载荷下，2.25 mm 时的最大有效吸收带宽为 6.24 GHz (11.76-18.00 GHz)。项链状结构、电介质和磁性材料的耦合效应以及异质界面形成了多重极化、导电损耗和多重损耗机制，优化了阻抗匹配和衰减性能，有利于实现优异的吸收性能。更重要的是，其雷达截面（RCS）降低率高达 24.02 dB m2，在实际应用环境中被证明具有良好的吸收效果。这项工作很好地结合了 Co@NCP 和 CNF 的优点，为设计具有轻质、强吸波性能的电磁波纳米复合纤维吸波材料提供了指导。
{"title":"Lightweight dielectric-magnetic synergistic necklace-shaped Co@NCP/carbon nanofiber composites for enhanced electromagnetic wave absorption","authors":"Dan Wu , Di Lan , Shijie Zhang , Qinchuan He , Xiping Zhou , Yiqun Wang","doi":"10.1016/j.mtnano.2024.100520","DOIUrl":"10.1016/j.mtnano.2024.100520","url":null,"abstract":"<div><div>In order to solve the problem of impedance mismatch of carbon fiber absorbing materials, it is crucial to create a carbon-based absorbing material with a special structure, synergistic magnetic and dielectric properties. In this paper, necklace-shaped Co@N-doped carbon polyhedron/carbon nanofiber (Co@NCP/CNF) composites with synergistic magnetic and dielectric properties are successfully fabricated by electrospinning. Compared with Co@NCP and CNF, the optimal minimum reflection loss of Co@NCP/CNF composite is −66.14 dB at 2.89 mm and the maximum effective absorption bandwidth is 6.24 GHz (11.76–18.00 GHz) at 2.25 mm at a low filler load of 10 wt%. The necklace-like structure, the coupling effect of dielectric and magnetic materials and the heterogeneous interface form multiple polarizations, conductive losses and multiple loss mechanisms to optimize impedance matching and attenuation performance, which is conducive to excellent absorption performance. More importantly, the radar cross section (RCS) reduction is as high as 24.02 dB m<sup>2</sup>, which has proven to have a good absorption effect in actual application environments. This work combines the advantages of Co@NCP and CNF very well, which provides guidance for designing EM waves nanocomposite fiber absorbers with lightweight and strong absorbing properties.</div></div>","PeriodicalId":48517,"journal":{"name":"Materials Today Nano","volume":"28 ","pages":"Article 100520"},"PeriodicalIF":8.2,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-26DOI: 10.1016/j.mtnano.2024.100519
Edgar J. Castanheira , João R. Maia , Luís P.G. Monteiro , Rita Sobreiro-Almeida , Nina K. Wittig , Henrik Birkedal , João M.M. Rodrigues , João F. Mano
Cryogels are known for their high water content and interconnected macroporosity, two relevant features in tissue engineering approaches. The cryogel structure can support tissue growth as it allows nutrient and oxygen diffusion, removal of waste products, as well as an enhancement of cell infiltration and proliferation. Bioactive glass nanoparticles are biocompatible and clinically approved bioactive materials widely used as implants in the human body to repair or replace diseased or damaged bones. They are known to facilitate bone binding while stimulating bone growth. Indeed, the combination of cryogels with bioactive nanoparticles has already demonstrated promising results for bone regeneration. Although the developed biomaterials succeed in bone regeneration, they lack suitability for minimal invasive procedures or patient-specificity. Here, we demonstrate a freeform 3D printed nanocomposite cryogel, resorting to an ink composed of functionalized gelatin and bioactive glass nanoparticles with methacrylate groups. Complex structures with multiple layers were 3D printed in a xanthan gum supporting bath. The developed 3D printed nanocomposite cryogels demonstrate the ability to recover their shape without any permanent damage, withstanding up to 65 % compression upon injection. Additionally, they stimulate the differentiation of human adipose-derived stem cells into the osteoblast lineage, therefore promoting bone tissue growth. We further demonstrated their suitability for minimal invasive therapeutics by filling a reproduction of a maxillofacial defect. The developed 3D-printed nanocomposite cryogels offer robust shape-recovery properties, easy injectability, tailored geometry into patient-specific injuries, and high osteogenic bioactivity, showcasing its versatility for bone regeneration purposes.
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Pub Date : 2024-09-23DOI: 10.1016/j.mtnano.2024.100518
Myles T. Blurton , Marc Walker , Fengzai Tang , Paul Ladislaus , Thomas Raine , Volkan Degirmenci , Tony McNally
The lack of a facile route for the functionalization of highly sp2 hybridized, low oxygen content (<10 atm%, C:O > 9:1) graphene nanoplatelets (GNP) has greatly hindered full exploitation of these materials. Moreover, the highly conductive and paramagnetic properties of GNP can exclude the use of solid-state nuclear magnetic resonance spectroscopy (SS-NMR) and electron paramagnetic resonance spectroscopy (EPR), even at liquid helium temperatures, to prove binding of silane to the GNP surface is successful. Here, three model silanes, 3-Mercaptopropyltrimethoxysilane, 3-Methacryloxypropyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane were successfully bound to the surface of GNP, each following either a condensation silanization reaction or a pathway dependent on the R-group of each silane. Several techniques were employed, but critically a combination of X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis-mass spectrometry (TGA-MS) in argon and air confirmed successful binding of the silane to the GNP. The approach adopted makes available the pendant R-group on the silane for interaction or reaction with polymers and a route to significantly modifying the properties of polymers and surfaces.
高sp2杂化、低氧含量（<10 atm%，C:O >9:1）的石墨烯纳米片（GNP）缺乏功能化的简便途径，这极大地阻碍了对这些材料的充分利用。此外，即使在液氦温度下，GNP 的高导电性和顺磁性也会使人们无法使用固态核磁共振光谱（SS-NMR）和电子顺磁共振光谱（EPR）来证明硅烷与 GNP 表面的结合是否成功。在这里，3-巯丙基三甲氧基硅烷、3-甲基丙烯酰氧基丙基三甲氧基硅烷和 N-（2-氨基乙基）-3-氨丙基三甲氧基硅烷这三种模型硅烷成功地结合到了 GNP 表面，每种硅烷都是通过缩合硅烷化反应或取决于每种硅烷的 R 基团的途径结合到 GNP 表面的。研究人员采用了多种技术，但最关键的是，在氩气和空气中结合使用 X 射线光电子能谱分析法（XPS）和热重分析-质谱分析法（TGA-MS）证实了硅烷与 GNP 的成功结合。所采用的方法使硅烷上的悬垂 R 基团可以与聚合物发生相互作用或反应，并提供了一条显著改变聚合物和表面特性的途径。
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Polybenzoxazine (PBz) aerogels are promising high-performance, halogen-free flame-retardant thermal insulation materials in aerospace applications. But their widespread use is hindered by high costs, significant drying shrinkage, and poor machinability. Herein, we successfully addressed these challenges by developing PBz aerogel composites using a cost-effective ambient pressure drying method that reduces energy consumption and shortening the preparation cycle. This approach expands the range of available monomers, reduces the inherent rigidity of the network structure, and enhances processability. The resulting PBz aerogels demonstrate low drying shrinkage (as low as 5.68 %), lightweight properties (lowest to 0.322 g cm−3), excellent fire-retardant (self-extinguishing in 1.8 s), and exceptional thermal insulation performance (as low as 0.0402 W m−1 K−1 at room temperature and normal pressure). Further studies under various pressures show that at an atmospheric pressure of 10 Pa, the thermal conductivity at room temperature can reach as low as 0.027 W m−1 K−1. Moreover, cryogenic treatment at −196 °C significantly enhances the compressive properties of PBz aerogels without inducing any noticeable shrinkage. Notably, PBz aerogels exhibit outstanding flame resistance, rated as nonflammable rating in vertical burning tests (UL-94, V-1 class), and showing a limiting oxygen index (LOI) as high as 33.7 %. Overall, these remarkable features underscore the exceptional potential of PBz aerogels as advanced thermal insulation materials in the aerospace industry.
聚苯并恶嗪（PBz）气凝胶是一种很有前途的高性能无卤阻燃隔热材料，可用于航空航天领域。但是，高昂的成本、显著的干燥收缩和较差的机加工性能阻碍了它们的广泛应用。在本文中，我们成功地解决了这些难题，采用经济有效的环境压力干燥法开发出了 PBz 气凝胶复合材料，降低了能耗，缩短了制备周期。这种方法扩大了可用单体的范围，降低了网络结构的固有刚性，并提高了可加工性。所制备的 PBz 气凝胶具有低干燥收缩率（低至 5.68%）、轻质特性（最低为 0.322 g cm-3）、优异的阻燃性（1.8 秒内自熄）和卓越的隔热性能（常温常压下低至 0.0402 W m-1 K-1）。在各种压力下进行的进一步研究表明，在 10 Pa 的大气压力下，室温下的导热系数可低至 0.027 W m-1 K-1。此外，在零下 196 摄氏度的低温条件下处理 PBz 气凝胶可显著提高其抗压性能，且不会引起任何明显的收缩。值得注意的是，PBz 气凝胶具有出色的阻燃性，在垂直燃烧测试（UL-94，V-1 级）中被评为不燃等级，极限氧指数（LOI）高达 33.7%。总之，这些显著特点凸显了 PBz 气凝胶作为先进隔热材料在航空航天领域的巨大潜力。
{"title":"Ambient drying to fabricate polybenzoxazine aerogels for thermal insulation in aerospace","authors":"Yanrong Liao , Sizhao Zhang , Zhouyuan Yang , Jing Wang , Shuai Yu , Haolin Zhang , Yunyun Xiao , Feng Ding","doi":"10.1016/j.mtnano.2024.100517","DOIUrl":"10.1016/j.mtnano.2024.100517","url":null,"abstract":"<div><p>Polybenzoxazine (PBz) aerogels are promising high-performance, halogen-free flame-retardant thermal insulation materials in aerospace applications. But their widespread use is hindered by high costs, significant drying shrinkage, and poor machinability. Herein, we successfully addressed these challenges by developing PBz aerogel composites using a cost-effective ambient pressure drying method that reduces energy consumption and shortening the preparation cycle. This approach expands the range of available monomers, reduces the inherent rigidity of the network structure, and enhances processability. The resulting PBz aerogels demonstrate low drying shrinkage (as low as 5.68 %), lightweight properties (lowest to 0.322 g cm<sup>−3</sup>), excellent fire-retardant (self-extinguishing in 1.8 s), and exceptional thermal insulation performance (as low as 0.0402 W m<sup>−1</sup> K<sup>−1</sup> at room temperature and normal pressure). Further studies under various pressures show that at an atmospheric pressure of 10 Pa, the thermal conductivity at room temperature can reach as low as 0.027 W m<sup>−1</sup> K<sup>−1</sup>. Moreover, cryogenic treatment at −196 °C significantly enhances the compressive properties of PBz aerogels without inducing any noticeable shrinkage. Notably, PBz aerogels exhibit outstanding flame resistance, rated as nonflammable rating in vertical burning tests (UL-94, V-1 class), and showing a limiting oxygen index (LOI) as high as 33.7 %. Overall, these remarkable features underscore the exceptional potential of PBz aerogels as advanced thermal insulation materials in the aerospace industry.</p></div>","PeriodicalId":48517,"journal":{"name":"Materials Today Nano","volume":"28 ","pages":"Article 100517"},"PeriodicalIF":8.2,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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