Pub Date : 2024-11-06DOI: 10.1016/j.mtphys.2024.101583
Lei Zhang, Yongqiang Yang, Yongping Pu, Min Chen, Ning Xu, Xia Wu
Low surface electric potential (<1V) limits the large-scale commercial application of ferroelectric antibacterial ceramics. We propose a strategy based on charge-balancing doping to enhance polarization and potential in NaNbO3(NN)-based ceramics for disinfection application. The Mg2+ modified NN showed a superior bactericidal effect greater than 80% for 1.5 h and 99.8% for 3 h without heating or ultrasonication, which is superior to other published works. This is mainly due to its excellent surface electric potential of 1.72 V and defect-related discharge current of 141.9 pA compared to NN and Ca2+ modified NN. Ferroelectric properties demonstrated that NN-Mg possesses a lower EC of ∼40 kV/cm and a higher Pr of ∼32 μC/cm2. Furthermore, the combination of XRD, Raman shift, PFM, and permittivity testing suggests that the smaller domain and enhanced ferroelectric properties in NN-Mg originated from amphoteric doping. Finally, simulation results of the electric field distribution indicated that NN-Mg had a stronger attraction or repulsion to bacteria with negatively charged surfaces.
低表面电势（1V）限制了铁电抗菌陶瓷的大规模商业应用。我们提出了一种基于电荷平衡掺杂的策略，以增强 NaNbO3（NN）基陶瓷的极化和电位，从而实现消毒应用。经 Mg2+ 修饰的 NN 在不加热或超声处理的情况下，1.5 小时内的杀菌效果大于 80%，3 小时内的杀菌效果大于 99.8%，优于其他已发表的研究成果。这主要是因为与 NN 和 Ca2+ 修饰的 NN 相比，其表面电动势为 1.72 V，缺陷相关放电电流为 141.9 pA。铁电特性表明，NN-Mg 具有较低的 EC（40 kV/cm）和较高的 Pr（32 μC/cm2）。此外，XRD、拉曼偏移、PFM 和介电常数测试的综合结果表明，NN-Mg 中更小的畴和更强的铁电特性源于两性掺杂。最后，电场分布的模拟结果表明，NN-Mg 对表面带负电荷的细菌具有更强的吸引力或排斥力。
{"title":"Novel NaNbO3-based, ferroelectric ceramics with excellent polarization and electric potential for antibacterial applications","authors":"Lei Zhang, Yongqiang Yang, Yongping Pu, Min Chen, Ning Xu, Xia Wu","doi":"10.1016/j.mtphys.2024.101583","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101583","url":null,"abstract":"Low surface electric potential (<1V) limits the large-scale commercial application of ferroelectric antibacterial ceramics. We propose a strategy based on charge-balancing doping to enhance polarization and potential in NaNbO<sub>3</sub>(NN)-based ceramics for disinfection application. The Mg<sup>2+</sup> modified NN showed a superior bactericidal effect greater than 80% for 1.5 h and 99.8% for 3 h without heating or ultrasonication, which is superior to other published works. This is mainly due to its excellent surface electric potential of 1.72 V and defect-related discharge current of 141.9 pA compared to NN and Ca<sup>2+</sup> modified NN. Ferroelectric properties demonstrated that NN-Mg possesses a lower <em>E</em><sub>C</sub> of ∼40 kV/cm and a higher <em>P</em><sub>r</sub> of ∼32 μC/cm<sup>2</sup>. Furthermore, the combination of XRD, Raman shift, PFM, and permittivity testing suggests that the smaller domain and enhanced ferroelectric properties in NN-Mg originated from amphoteric doping. Finally, simulation results of the electric field distribution indicated that NN-Mg had a stronger attraction or repulsion to bacteria with negatively charged surfaces.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":11.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594304","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}
High-performance infrared radiation materials with excellent broadband emissivity, remarkable thermal stability, and scalable fabrication processes play a vital role in heat dissipation and energy-saving applications. However, current strategies of broadband emissivity enhancement remain inadequate. This study investigates the impact of LaPO4 morphology on the infrared radiation properties of composite coating. Three distinct morphologies (sphere, rod and mesh sheet) of LaPO4 are explored using a simulation-aided method. The composite coating filled with large-sized spherical LaPO4 particles with low diffuse reflection, exhibits a significantly enhanced infrared radiation capability, resulting in a broadband emissivity of 95.6%. Furthermore, the composite coating achieves a large temperature reduction of 6.2 °C and high cooling efficiency of 11.9% when subjected to a heating power of 2250 W/m2. This work provides an innovative strategy for regulating material emissivity through morphology control, benefiting advancements low-cost radiation heat transfer technology.
{"title":"Multiple scattering effect of spherical LaPO4 enhanced broadband emissivity for heat dissipation of electronic devices","authors":"Chuanqing Sun, Mingrui Liu, Wei Song, Chenxi Bao, Wanting Zhu, Wenyu Zhao, Qingjie Zhang","doi":"10.1016/j.mtphys.2024.101584","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101584","url":null,"abstract":"High-performance infrared radiation materials with excellent broadband emissivity, remarkable thermal stability, and scalable fabrication processes play a vital role in heat dissipation and energy-saving applications. However, current strategies of broadband emissivity enhancement remain inadequate. This study investigates the impact of LaPO<sub>4</sub> morphology on the infrared radiation properties of composite coating. Three distinct morphologies (sphere, rod and mesh sheet) of LaPO<sub>4</sub> are explored using a simulation-aided method. The composite coating filled with large-sized spherical LaPO<sub>4</sub> particles with low diffuse reflection, exhibits a significantly enhanced infrared radiation capability, resulting in a broadband emissivity of 95.6%. Furthermore, the composite coating achieves a large temperature reduction of 6.2 °C and high cooling efficiency of 11.9% when subjected to a heating power of 2250 W/m<sup>2</sup>. This work provides an innovative strategy for regulating material emissivity through morphology control, benefiting advancements low-cost radiation heat transfer technology.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":11.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588393","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}
Magnons, quantized spin waves arising from collective excitations of spins, are typically considered negligible contributors to heat transfer. However, recent studies on low-dimensional magnetic materials have challenged this notion, revealing significant magnon-mediated heat transport. The underlying physics behind this phenomenon, however, remains poorly understood. In this study, we observed a significant reduction in heat transfer in nickel nanowires under the influence of a magnetic field. Our theoretical model revealed a substantial magnon contribution of up to 30% to nanowire heat transfer. The reduction in heat transfer under a magnetic field stemmed from a drastic decrease in the magnon mean free path (MFP). This decrease in MFP was primarily attributed to suppressing long wavelength magnons with a longer MFP. Our findings provide deeper insights into heat transfer mechanisms in nanoscale ferromagnetic materials and offer valuable guidance for the design of future spintronic devices.
{"title":"Significant Magnon Contribution to Heat Transfer in Nickel Nanowires","authors":"Wei-Tsu Peng, Jiun-Hung Yi, Chih-Cheng Cheng, Kuan-Ju Yu, Tien-Kan Chung, Ming-Chang Lu","doi":"10.1016/j.mtphys.2024.101585","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101585","url":null,"abstract":"Magnons, quantized spin waves arising from collective excitations of spins, are typically considered negligible contributors to heat transfer. However, recent studies on low-dimensional magnetic materials have challenged this notion, revealing significant magnon-mediated heat transport. The underlying physics behind this phenomenon, however, remains poorly understood. In this study, we observed a significant reduction in heat transfer in nickel nanowires under the influence of a magnetic field. Our theoretical model revealed a substantial magnon contribution of up to 30% to nanowire heat transfer. The reduction in heat transfer under a magnetic field stemmed from a drastic decrease in the magnon mean free path (MFP). This decrease in MFP was primarily attributed to suppressing long wavelength magnons with a longer MFP. Our findings provide deeper insights into heat transfer mechanisms in nanoscale ferromagnetic materials and offer valuable guidance for the design of future spintronic devices.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":11.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588418","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 : 2024-11-06DOI: 10.1016/j.mtphys.2024.101582
Haoyu Li, Hongyi Xiao, Takeshi Egami, Yue Fan
The absence of translational symmetry in glassy materials poses a significant challenge in establishing effective structure-property relationships in real space. Consequently, the potential energy landscape (PEL) in phase space is widely utilized to comprehend the complex phenomena in glasses. The classical PEL features a two-scale profile comprising mega-basins and sub-basins, corresponding to α-relaxations (e.g. glass transition) and β-relaxations (e.g. local cage-breaking atomic rearrangements), respectively. Recent studies, however, reveal that sub-basins are not smooth and contain finer structures, the origins of which remain elusive. Here we probe the smoothness of sub-basin bottoms in glasses’ PEL by introducing small intra-cage cyclic loading and then measuring the net changes in atomic-level stresses. Compared to glasses with pair interaction, glasses with many-body interaction exhibit orders-of-magnitude larger and loading dependent stress changes even before the first cage-breaking event takes place, which reflect much more feature-rich sub-basins. We further demonstrate this stark contrast stems from the spatial distribution of individual atom’s constraining force field. Specifically, at vanishing perturbations, many-body interactions disrupt the positive-definite synchrony in energy variations of the perturbed atom and the whole system, causing inherently less confined atomic responses and infinitely rugged sub-basins. The implications of these findings for the selective addition or removal of fine structures in the PEL and the subsequent tuning of glassy materials’ responses to external stimuli are also explored.
玻璃材料不存在平移对称性，这给在实际空间中建立有效的结构-性能关系带来了巨大挑战。因此，相空间势能图（PEL）被广泛用于理解玻璃中的复杂现象。经典的势能图具有双尺度剖面，包括巨盆地和子盆地，分别对应于α-松弛（如玻璃转变）和β-松弛（如局部破笼原子重排）。然而，最近的研究发现，亚盆地并不光滑，它包含更精细的结构，而这些结构的起源仍然难以捉摸。在此，我们通过引入小的笼内循环加载，然后测量原子级应力的净变化，来探究玻璃 PEL 中子盆地底部的平滑性。与具有配对相互作用的玻璃相比，具有多体相互作用的玻璃甚至在第一次破笼事件发生之前就表现出了数量级更大且与加载相关的应力变化，这反映了特征更为丰富的子盆地。我们进一步证明，这种鲜明对比源于单个原子约束力场的空间分布。具体来说，在扰动消失时，多体相互作用会破坏受扰动原子和整个系统能量变化的正无限同步性，从而导致原子反应的内在约束性降低和子盆地的无限崎岖。此外，还探讨了这些发现对选择性添加或去除 PEL 中的精细结构以及随后调整玻璃材料对外部刺激的反应的影响。
{"title":"Infinitely Rugged Intra-Cage Potential Energy Landscape in Metallic Glasses Caused by Many-Body Interaction","authors":"Haoyu Li, Hongyi Xiao, Takeshi Egami, Yue Fan","doi":"10.1016/j.mtphys.2024.101582","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101582","url":null,"abstract":"The absence of translational symmetry in glassy materials poses a significant challenge in establishing effective structure-property relationships in real space. Consequently, the potential energy landscape (PEL) in phase space is widely utilized to comprehend the complex phenomena in glasses. The classical PEL features a two-scale profile comprising mega-basins and sub-basins, corresponding to α-relaxations (<em>e.g.</em> glass transition) and β-relaxations (<em>e.g.</em> local cage-breaking atomic rearrangements), respectively. Recent studies, however, reveal that sub-basins are not smooth and contain finer structures, the origins of which remain elusive. Here we probe the smoothness of sub-basin bottoms in glasses’ PEL by introducing small intra-cage cyclic loading and then measuring the net changes in atomic-level stresses. Compared to glasses with pair interaction, glasses with many-body interaction exhibit orders-of-magnitude larger and loading dependent stress changes even before the first cage-breaking event takes place, which reflect much more feature-rich sub-basins. We further demonstrate this stark contrast stems from the spatial distribution of individual atom’s constraining force field. Specifically, at vanishing perturbations, many-body interactions disrupt the positive-definite synchrony in energy variations of the perturbed atom and the whole system, causing inherently less confined atomic responses and infinitely rugged sub-basins. The implications of these findings for the selective addition or removal of fine structures in the PEL and the subsequent tuning of glassy materials’ responses to external stimuli are also explored.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":11.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594296","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 : 2024-11-01DOI: 10.1016/j.mtphys.2024.101580
Kesterite solar cells show great potential for sustainable photovoltaic technology, attributed to their excellent semiconductor properties and earth abundant composition. However, undesirable band bending at the grain boundaries (GBs) in Cu2ZnSn(S,Se)4 (CZTSSe) films induces serious carrier recombination because of inhomogeneous distribution of S and Se in the grain interiors (GIs) and at GBs, which results in large open-circuit voltage deficit and overall poor performance of CZTSSe solar cells. Here, a robust hydrothermal sulfurization design has successfully inverted the band bending at the GBs, with advanced cathodoluminescence measurement confirming the transition of carrier collection pathways from the GBs to the GIs, thereby achieving efficient carrier collection within the GIs. Simultaneously, this design has effectively passivated the non-radiative recombination in the GIs, smoothing the way for carrier collection. Ultimately, a 13.7 % efficiency CZTSSe solar cell with 44 % improvement is realized by this process. This study discloses that reversing the band bending at GBs is practical to tailor the carrier collection, and thus pave the pathway for high-efficient photoelectronic devices.
{"title":"Reversing band bending at grain boundaries enables high-efficiency Cu2ZnSn(S,Se)4 solar cells","authors":"","doi":"10.1016/j.mtphys.2024.101580","DOIUrl":"10.1016/j.mtphys.2024.101580","url":null,"abstract":"<div><div>Kesterite solar cells show great potential for sustainable photovoltaic technology, attributed to their excellent semiconductor properties and earth abundant composition. However, undesirable band bending at the grain boundaries (GBs) in Cu<sub>2</sub>ZnSn(S,Se)<sub>4</sub> (CZTSSe) films induces serious carrier recombination because of inhomogeneous distribution of S and Se in the grain interiors (GIs) and at GBs, which results in large open-circuit voltage deficit and overall poor performance of CZTSSe solar cells. Here, a robust hydrothermal sulfurization design has successfully inverted the band bending at the GBs, with advanced cathodoluminescence measurement confirming the transition of carrier collection pathways from the GBs to the GIs, thereby achieving efficient carrier collection within the GIs. Simultaneously, this design has effectively passivated the non-radiative recombination in the GIs, smoothing the way for carrier collection. Ultimately, a 13.7 % efficiency CZTSSe solar cell with 44 % improvement is realized by this process. This study discloses that reversing the band bending at GBs is practical to tailor the carrier collection, and thus pave the pathway for high-efficient photoelectronic devices.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142541509","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}
Germanium Telluride (GeTe) has been widely explored as a promising lead-free thermoelectric material in its rhombohedral and cubic phases. However, the structural transition between these two phases at ∼700 K causes an abrupt change of thermal expansion coefficient, challenging its broader practical applications. Also, as characterized by multi-valence bands and strong anharmonic interaction, the high-temperature cubic phase exhibits a higher power factor, lower thermal conductivity, and ultimately superior thermoelectric performance than its rhombohedral counterpart. Prompted by these, in this work, the cubic phase of Ge0.9Sb0.1Te (presented as GeSbTe in the following content) nanocrystalline thin film is successfully realized by RF sputtering followed by post-annealing treatment. Additionally, Indium, as an electron donor to the germanium site and an effective scattering center, further moderates carrier concentration, enhances the Seebeck coefficient and reduces thermal conductivity. The optimal composition achieves an estimated peak of ∼1.95 and an estimated average of ∼ 1.11 within the temperature range of 300 K to 575 K, showcasing GeTe as a compelling candidate for applications close to room temperature.
碲化镉锗（GeTe）的斜方体相和立方体相作为一种前景广阔的无铅热电材料已被广泛探索。然而，这两种相在 ∼700 K 时的结构转变会导致热膨胀系数的突然变化，这对其更广泛的实际应用提出了挑战。此外，高温立方相具有多价带和强非谐相互作用的特点，与斜方体相相比，其功率因数更高，热导率更低，热电性能更优。有鉴于此，在这项工作中，通过射频溅射和退火后处理，成功实现了 Ge0.9Sb0.1Te（下文中称为 GeSbTe）纳米晶薄膜的立方相。此外，铟作为锗位点的电子供体和有效的散射中心，进一步缓和了载流子浓度，提高了塞贝克系数并降低了热导率。在 300 K 至 575 K 的温度范围内，最佳成分的峰值估计为 ∼ 1.95，平均值估计为 ∼ 1.11，这表明 GeTe 是接近室温应用的理想候选材料。
{"title":"Synergistic effect of indium doping on thermoelectric performance of cubic GeTe-based thin films","authors":"Suman Abbas, Bhawna Jarwal, Thi-Thong Ho, Suneesh Meledath Valiyaveettil, Cheng-Rong Hsing, Ta-Lei Chou, Ching-Ming Wei, Li-Chyong Chen, Kuei-Hsien Chen","doi":"10.1016/j.mtphys.2024.101581","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101581","url":null,"abstract":"Germanium Telluride (GeTe) has been widely explored as a promising lead-free thermoelectric material in its rhombohedral and cubic phases. However, the structural transition between these two phases at ∼700 K causes an abrupt change of thermal expansion coefficient, challenging its broader practical applications. Also, as characterized by multi-valence bands and strong anharmonic interaction, the high-temperature cubic phase exhibits a higher power factor, lower thermal conductivity, and ultimately superior thermoelectric performance than its rhombohedral counterpart. Prompted by these, in this work, the cubic phase of Ge<sub>0.9</sub>Sb<sub>0.1</sub>Te (presented as GeSbTe in the following content) nanocrystalline thin film is successfully realized by RF sputtering followed by post-annealing treatment. Additionally, Indium, as an electron donor to the germanium site and an effective scattering center, further moderates carrier concentration, enhances the Seebeck coefficient and reduces thermal conductivity. The optimal composition achieves an estimated peak <span><math></math></span> of ∼1.95 and an estimated average <span><math></math></span> of ∼ 1.11 within the temperature range of 300 K to 575 K, showcasing GeTe as a compelling candidate for applications close to room temperature.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":11.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142562243","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 : 2024-10-25DOI: 10.1016/j.mtphys.2024.101578
The development of lightweight and highly heat-resistant polyimide foams (PIFs) remains a great challenge in areas of aerospace, military ships, transportation, and industries. Herein, a series of lightweight and highly thermal-resistant copolymerized PIFs are successfully fabricated by the “stepwise heating-holding” thermal foaming of the copolymerized polyester ammonium salts (C-PEAS), using 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 2,3,3′,4′-biphenyl tetracarboxylic acid dianhydride (α-BPDA) as codianhydride, and p-phenylenediamine (PDA) as diamine. The introduction of α-BPDA increases the rigidity of PI molecule chains and foamability of C-PEAS, and significantly improves the heat resistance of PIFs. The resultant copolymerized PIFs exhibit ultra-low densities (<10 kg m−3), excellent heat resistance (Tg ranging from 351.2 °C to 405.6 °C), and high thermal stability. Moreover, they possess high flame retardancies (LOI>44 %) and low thermal conductivities (as low as 0.0463 W m−1 K−1 at 20 °C and no more than 0.0825 W m−1 K−1 at 200 °C), demonstrating their excellent thermal insulation properties in a wide temperature range. After the continuous heating at 200 °C for 40 min, the upper surface of PIFs present low average temperatures less than 60 °C. Additionally, the copolymerized PIFs exhibit remarkable acoustic properties with average acoustic absorption coefficients above 0.6 and noise reduction coefficients (NRC) above 0.3. Therefore, the lightweight and highly heat-resistant copolymerized PIFs show great application potentials in the extreme environments of aerospace, military ships, transportation, and industries.
{"title":"Lightweight and highly heat-resistant copolymerized polyimide foams for superior thermal insulation and acoustic absorption","authors":"","doi":"10.1016/j.mtphys.2024.101578","DOIUrl":"10.1016/j.mtphys.2024.101578","url":null,"abstract":"<div><div>The development of lightweight and highly heat-resistant polyimide foams (PIFs) remains a great challenge in areas of aerospace, military ships, transportation, and industries. Herein, a series of lightweight and highly thermal-resistant copolymerized PIFs are successfully fabricated by the “stepwise heating-holding” thermal foaming of the copolymerized polyester ammonium salts (C-PEAS), using 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 2,3,3′,4′-biphenyl tetracarboxylic acid dianhydride (α-BPDA) as codianhydride, and p-phenylenediamine (PDA) as diamine. The introduction of α-BPDA increases the rigidity of PI molecule chains and foamability of C-PEAS, and significantly improves the heat resistance of PIFs. The resultant copolymerized PIFs exhibit ultra-low densities (<10 kg m<sup>−3</sup>), excellent heat resistance (<em>T</em><sub>g</sub> ranging from 351.2 °C to 405.6 °C), and high thermal stability. Moreover, they possess high flame retardancies (LOI>44 %) and low thermal conductivities (as low as 0.0463 W m<sup>−1</sup> K<sup>−1</sup> at 20 °C and no more than 0.0825 W m<sup>−1</sup> K<sup>−1</sup> at 200 °C), demonstrating their excellent thermal insulation properties in a wide temperature range. After the continuous heating at 200 °C for 40 min, the upper surface of PIFs present low average temperatures less than 60 °C. Additionally, the copolymerized PIFs exhibit remarkable acoustic properties with average acoustic absorption coefficients above 0.6 and noise reduction coefficients (NRC) above 0.3. Therefore, the lightweight and highly heat-resistant copolymerized PIFs show great application potentials in the extreme environments of aerospace, military ships, transportation, and industries.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489204","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 : 2024-10-23DOI: 10.1016/j.mtphys.2024.101576
Global research on flexible pressure sensors for evaluating human wellness and intelligent robotics is intensifying due to their advantages of excellent flexibility, lightweight design, high sensitivity and ease of integration. To facilitate practical applications, challenges associated with high-performance must be addressed, such as the trade-off between high sensitivity and a wide linear sensing range, fast response/recovery time, limited hysteresis, and stability under both dynamic and static pressure conditions. Moreover, ensuring the sensors’ reliability under various interferences and their multi-functionality to meet diverse usage requirements is essential for future applications. In this review, we summarize the latest advancements in multiple microstructures within the active layer and/or electrodes, which ensure excellent sensing performances, superior reliability and multifunctional features. Specifically, we focus on the design, working principles and sensing features of advanced micropattern, micropores, fiber-network, and hybrid microstructures in pressure sensors based on hierarchical micro-/nano-structure, conductive gradient coatings or multilayer structures. Additionally, the applications of microstructured pressure sensors in the fields of healthcare and human-machine interaction are summarized. Finally, we discuss the challenges and future prospects in the development of the next generation of flexible pressure sensors.
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