The heterogeneity in the state of charge (SOC) across electrodes can significantly abbreviate battery lifespan, deteriorate safety metrics, and diminish capability rate. Despite being a known issue for some time, the factors contributing to this phenomenon have not been systematically summarized. Without a thorough understanding of the underlying causes, it is difficult to devise preventive strategies that can effectively enhance electrode behavior. This paper provides a comprehensive analysis of the factors inducing electrode SOC heterogeneity, identifying the unequal distribution of ions and electrons as the primary cause of the varied reaction rates across the electrode, which ultimately leads to SOC heterogeneity. Subsequently, preventive measures are outlined with a focus on electrode composition and structure. Furthermore, implications of SOC heterogeneity and the challenges associated with achieving both large power density and high energy density in electrodes are discussed. A more profound grasp of the mechanisms governing ion and electron conduction, coupled with materials that can resolve these dilemmas into win–win outcomes, is essential for the advancement of electrodes.
{"title":"Rational Electrode Design for Enhanced Battery Performance: Addressing SOC Heterogeneity and Achieving Energy Density","authors":"Ziwen Yan, Li Wang, Xiangming He","doi":"10.1002/adfm.202415637","DOIUrl":"https://doi.org/10.1002/adfm.202415637","url":null,"abstract":"The heterogeneity in the state of charge (SOC) across electrodes can significantly abbreviate battery lifespan, deteriorate safety metrics, and diminish capability rate. Despite being a known issue for some time, the factors contributing to this phenomenon have not been systematically summarized. Without a thorough understanding of the underlying causes, it is difficult to devise preventive strategies that can effectively enhance electrode behavior. This paper provides a comprehensive analysis of the factors inducing electrode SOC heterogeneity, identifying the unequal distribution of ions and electrons as the primary cause of the varied reaction rates across the electrode, which ultimately leads to SOC heterogeneity. Subsequently, preventive measures are outlined with a focus on electrode composition and structure. Furthermore, implications of SOC heterogeneity and the challenges associated with achieving both large power density and high energy density in electrodes are discussed. A more profound grasp of the mechanisms governing ion and electron conduction, coupled with materials that can resolve these dilemmas into win–win outcomes, is essential for the advancement of electrodes.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"1 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiafei Gao, Yuping Pan, Janghui Qiu, Juan Peng, Shuangyin Wang, Yuqin Zou
Electrocatalytic formaldehyde oxidation with metal Cu electrocatalyst has attracted significant interest since it can produce H2 at the anode and make it possible to construct a bipolar hydrogen production cell with low voltage. However, the activity of the Cu electrocatalyst will be greatly weakened after oxidizing it to Cu+ or Cu2+. Here, a CuFe bimetallic catalyst is developed to efficiently catalyze the electro-oxidation process of HCHO to produce H2 at a potential of 0.10 VRHE with a current density of 100 mA cm−2. It is confirmed that introducing Fe in a CuFe catalyst can regulate the electron configuration to prevent Cu0 oxidation and improve the stability of the catalysts. The introduction of Fe can reduce the energy barrier of the reaction process, and make the C─H bond more easily split on CuFe. A bipolar hydrogen production device is constructed by combining the anodic oxidation of HCHO with the cathodic hydrogen evolution. The current density of 500 mA cm−2 is achieved at a cell voltage of 0.6 V. The faradaic efficiency is ≈100% and the device is stable for ≈50 h. The research provides a promising path toward the secure, effective, and expandable generation of high-purity H2 at both anodic and cathodic electrodes.
{"title":"Enhancing the Stability of Cu-Based Electrocatalyst via Fe Alloy in Electrocatalytic Formaldehyde Oxidation with Long Durability","authors":"Xiafei Gao, Yuping Pan, Janghui Qiu, Juan Peng, Shuangyin Wang, Yuqin Zou","doi":"10.1002/adfm.202417545","DOIUrl":"https://doi.org/10.1002/adfm.202417545","url":null,"abstract":"Electrocatalytic formaldehyde oxidation with metal Cu electrocatalyst has attracted significant interest since it can produce H<sub>2</sub> at the anode and make it possible to construct a bipolar hydrogen production cell with low voltage. However, the activity of the Cu electrocatalyst will be greatly weakened after oxidizing it to Cu<sup>+</sup> or Cu<sup>2+</sup>. Here, a CuFe bimetallic catalyst is developed to efficiently catalyze the electro-oxidation process of HCHO to produce H<sub>2</sub> at a potential of 0.10 V<sub>RHE</sub> with a current density of 100 mA cm<sup>−2</sup>. It is confirmed that introducing Fe in a CuFe catalyst can regulate the electron configuration to prevent Cu<sup>0</sup> oxidation and improve the stability of the catalysts. The introduction of Fe can reduce the energy barrier of the reaction process, and make the C─H bond more easily split on CuFe. A bipolar hydrogen production device is constructed by combining the anodic oxidation of HCHO with the cathodic hydrogen evolution. The current density of 500 mA cm<sup>−2</sup> is achieved at a cell voltage of 0.6 V. The faradaic efficiency is ≈100% and the device is stable for ≈50 h. The research provides a promising path toward the secure, effective, and expandable generation of high-purity H<sub>2</sub> at both anodic and cathodic electrodes.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"12 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The molecular self-organization and reorganization and thus volumetric and density changes during structural relaxation and melting of modern organic semi-conducting materials remains largely unknown, particularly in the device relevant thin film geometry where the initial state may be structurally quenched away from equilibrium. Here, the apparent mass-thickness of a range of semi-conducting polymeric or molecular model materials systems is measured through in situ ellipsometry. Surprisingly, the volume changes upon melting correlate inversely, with a few exceptions, to the quality of crystallinity found via x-ray methods (i.e., directly correlate with the paracrystalline g-parameter) rather than the melting enthalpy that is possibly a proxy for the degree of crystallinity. This study also observes changes in orientation and/or density due to segmental relaxation during the first heat, thus complementing other characterization methods that measure relaxation or reorganization transitions. Semiconducting materials exhibit very large melt expansion and a richer phase-behavior compared to commodity polymers, presumably due to their complex chemical structure. The results delineate an important and novel structure-function relation that, together with simulations constrained by these results, will lead to better rational design of semi-conducting materials.
现代有机半导材料在结构松弛和熔化过程中的分子自组织和重组，以及由此产生的体积和密度变化在很大程度上仍不为人所知，尤其是在与设备相关的薄膜几何形状中，初始状态可能在结构上偏离平衡状态。在此，我们通过原位椭偏仪测量了一系列半导聚合物或分子模型材料系统的表观质量厚度。令人惊讶的是，熔化时的体积变化与通过 X 射线方法发现的结晶度质量成反比（即与准结晶 g 参数直接相关），只有少数例外，而与可能代表结晶度的熔化焓成反比。这项研究还能观察到在第一次加热过程中由于片段松弛而导致的取向和/或密度变化，从而补充了其他测量松弛或重组转变的表征方法。与普通聚合物相比，半导体材料表现出非常大的熔体膨胀和更丰富的相行为，这可能是由于其复杂的化学结构造成的。这些结果勾勒出了一种重要而新颖的结构-功能关系，结合受这些结果制约的模拟，将有助于更好地合理设计半导体材料。
{"title":"Melt Expansion and Thermal Transitions of Semiconducting Polymers in Thin Films","authors":"Reece Henry, Harald Ade","doi":"10.1002/adfm.202409465","DOIUrl":"https://doi.org/10.1002/adfm.202409465","url":null,"abstract":"The molecular self-organization and reorganization and thus volumetric and density changes during structural relaxation and melting of modern organic semi-conducting materials remains largely unknown, particularly in the device relevant thin film geometry where the initial state may be structurally quenched away from equilibrium. Here, the apparent mass-thickness of a range of semi-conducting polymeric or molecular model materials systems is measured through in situ ellipsometry. Surprisingly, the volume changes upon melting correlate inversely, with a few exceptions, to the quality of crystallinity found via x-ray methods (i.e., directly correlate with the paracrystalline g-parameter) rather than the melting enthalpy that is possibly a proxy for the degree of crystallinity. This study also observes changes in orientation and/or density due to segmental relaxation during the first heat, thus complementing other characterization methods that measure relaxation or reorganization transitions. Semiconducting materials exhibit very large melt expansion and a richer phase-behavior compared to commodity polymers, presumably due to their complex chemical structure. The results delineate an important and novel structure-function relation that, together with simulations constrained by these results, will lead to better rational design of semi-conducting materials.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"40 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinwook Baek, Yuxuan Zhang, Fei Qin, Xingyu Fu, Min-Seok Kim, Han-Wook Song, Jung-Hyun Oh, Garam Kim, Sunghwan Lee
Recent advancements in 3D printing technology have expanded its application to manufacturing pressure sensors. By harnessing the cost-effectiveness, streamlined processes, and design flexibility of 3D printing, sensor fabrication can be customized to meet specific performance needs. Thus far, 3D printing in pressure sensor development has been primarily limited to creating molds for transferring patterns onto flexible substrates, restricting both material selection and sensor performance. To fully unlock the potential of 3D printing in advanced pressure sensor fabrication, it is crucial to establish effective design rules focused on enhancing the figure of merit performance. This study introduces a universal design strategy aimed at maintaining high sensitivity across a wide pressure range—a challenging feat, as sensitivity significantly decreases at higher pressures. Our approach centers on engineering the deformability of 3D-printed structures, achieving a linear increase in contact area between sensor patterns and electrodes without reaching saturation. Sensors designed with high elongation and low stiffness exhibit consistent sensitivity of 162.5 kPa⁻¹ across a broad pressure range (0.05–300 kPa). Mechanistic investigations through finite element analysis confirm that engineered deformability is key to achieving this enhanced linear response, offering robust sensing capabilities for demanding applications such as deep-sea and space exploration.
三维打印技术的最新进展扩大了其在压力传感器制造方面的应用。利用三维打印技术的成本效益、简化流程和设计灵活性，可以定制传感器制造，以满足特定的性能需求。迄今为止，3D 打印在压力传感器开发中的应用主要局限于创建用于将图案转移到柔性基底上的模具，从而限制了材料选择和传感器性能。要充分释放 3D 打印在先进压力传感器制造中的潜力，关键是要建立有效的设计规则，重点提高性能指标。本研究介绍了一种通用设计策略，旨在在较宽的压力范围内保持高灵敏度--这是一项具有挑战性的成就，因为灵敏度在较高压力下会显著降低。我们的方法以三维打印结构的可变形性为中心，在不达到饱和的情况下实现传感器图案与电极之间接触面积的线性增加。采用高伸长率和低刚度设计的传感器在广泛的压力范围（0.05-300 kPa）内表现出一致的灵敏度（162.5 kPa-¹）。通过有限元分析进行的机理研究证实，工程变形能力是实现这种增强型线性响应的关键，为深海和太空探索等要求苛刻的应用提供了强大的传感能力。
{"title":"Design Rules for 3D Printing-Assisted Pressure Sensor Manufacturing: Achieving Broad Pressure Range Linearity","authors":"Jinwook Baek, Yuxuan Zhang, Fei Qin, Xingyu Fu, Min-Seok Kim, Han-Wook Song, Jung-Hyun Oh, Garam Kim, Sunghwan Lee","doi":"10.1002/adfm.202414050","DOIUrl":"https://doi.org/10.1002/adfm.202414050","url":null,"abstract":"Recent advancements in 3D printing technology have expanded its application to manufacturing pressure sensors. By harnessing the cost-effectiveness, streamlined processes, and design flexibility of 3D printing, sensor fabrication can be customized to meet specific performance needs. Thus far, 3D printing in pressure sensor development has been primarily limited to creating molds for transferring patterns onto flexible substrates, restricting both material selection and sensor performance. To fully unlock the potential of 3D printing in advanced pressure sensor fabrication, it is crucial to establish effective design rules focused on enhancing the figure of merit performance. This study introduces a universal design strategy aimed at maintaining high sensitivity across a wide pressure range—a challenging feat, as sensitivity significantly decreases at higher pressures. Our approach centers on engineering the deformability of 3D-printed structures, achieving a linear increase in contact area between sensor patterns and electrodes without reaching saturation. Sensors designed with high elongation and low stiffness exhibit consistent sensitivity of 162.5 kPa⁻¹ across a broad pressure range (0.05–300 kPa). Mechanistic investigations through finite element analysis confirm that engineered deformability is key to achieving this enhanced linear response, offering robust sensing capabilities for demanding applications such as deep-sea and space exploration.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"158 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solution-processed memristor devices hold significant potential for advancing synaptic applications, offering scalable, cost-effective, and efficient solutions for next-generation neuromorphic systems. These devices replicate the behavior of biological synapses with their gradual and continuous changes in resistance, making them promising for neuromorphic computing and artificial neural networks. However, understanding the temporal characteristics and cumulative effect of successive pulses on the devices is essential for emulating the dynamics of biological synapses. This study proposes a hybrid materials-based conductive islands-assisted resistive switching (CIARS) in a solution-processed active layer consisting of thermally exfoliated graphitic carbon nitride (g-C3N4 abbreviated as CN) nanosheets embedded with silver nanoparticles (Ag NPs). The fabricated devices demonstrate repeatable and bipolar memory features with a lower operating voltage (≤0.5 V), emulating the frequency and amplitude-dependent synaptic plasticities. The threshold switching occurs due to the formation of conduction filaments (CFs) of silver ion (Ag+), whereas the analog behavior results from the voltage pulse-dependent modulation of Schottky barrier height combined with metallic CFs formation. The experimental findings demonstrate the efficacy of the CIARS mechanism within the material platform, highlighting its potential for applications in associative learning, Morse code detection, and image recognition.
{"title":"Conductive Islands Assisted Resistive Switching in Biomimetic Artificial Synapse for Associative Learning and Image Recognition","authors":"Rajesh Jana, Ritamay Bhunia, Swapnamoy Paramanik, Kinsuk Giri, Avijit Chowdhury","doi":"10.1002/adfm.202412804","DOIUrl":"https://doi.org/10.1002/adfm.202412804","url":null,"abstract":"Solution-processed memristor devices hold significant potential for advancing synaptic applications, offering scalable, cost-effective, and efficient solutions for next-generation neuromorphic systems. These devices replicate the behavior of biological synapses with their gradual and continuous changes in resistance, making them promising for neuromorphic computing and artificial neural networks. However, understanding the temporal characteristics and cumulative effect of successive pulses on the devices is essential for emulating the dynamics of biological synapses. This study proposes a hybrid materials-based conductive islands-assisted resistive switching (CIARS) in a solution-processed active layer consisting of thermally exfoliated graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub> abbreviated as CN) nanosheets embedded with silver nanoparticles (Ag NPs). The fabricated devices demonstrate repeatable and bipolar memory features with a lower operating voltage (≤0.5 <i>V</i>), emulating the frequency and amplitude-dependent synaptic plasticities. The threshold switching occurs due to the formation of conduction filaments (CFs) of silver ion (Ag<sup>+</sup>), whereas the analog behavior results from the voltage pulse-dependent modulation of Schottky barrier height combined with metallic CFs formation. The experimental findings demonstrate the efficacy of the CIARS mechanism within the material platform, highlighting its potential for applications in associative learning, Morse code detection, and image recognition.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"39 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142602007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The global water crisis, exacerbated by excessive use and pollution, has resulted in energy scarcity and threats. Solar desalination provides a sustainable fix, with researchers developing photothermal materials and designs to improve efficiency and sustainability. Glass materials, with their exceptional chemical stability, are suitable for extreme desalination in acidic and alkaline conditions. In this work, we have developed a porous glass evaporator (PGE) with exceptional water evaporation efficiency, achieved through a novel fabrication method that blends glass powders with soluble salts to create structure with continuous pores. The evaporator's microstructure comprises micrometer-scale pores that form interconnected porous channels, facilitating efficient water transport and preventing salt deposition. Under one sun irradiation, the PGE exhibits superior solar evaporation performance in pure water, achieving a rate of 2.21 kg m−2 h−1, with an evaporation efficiency of 98%. In more complex media, such as seawater and methylene blue solution, the PGE also displays excellent evaporation capabilities, reaching rates of 2.08 and 2.47 kg m−2 h−1, respectively. Even after sustained alternation between acidic and alkaline treatments, the PGE retains an impressive evaporation rate of over 2.0 kg m−2 h−1, coupled with structural robustness, making it a promising candidate for practical applications in extreme environments.
过度使用和污染加剧了全球水危机，并导致能源短缺和威胁。太阳能海水淡化提供了一种可持续的解决方案，研究人员正在开发光热材料和设计，以提高效率和可持续性。玻璃材料具有优异的化学稳定性，适用于酸性和碱性条件下的极端海水淡化。在这项工作中，我们开发了一种多孔玻璃蒸发器 (PGE)，通过一种新颖的制造方法，将玻璃粉与可溶性盐混合，形成具有连续孔隙的结构，从而实现了极高的水蒸发效率。蒸发器的微观结构由微米级的孔隙组成，这些孔隙形成相互连接的多孔通道，有利于水的高效传输并防止盐分沉积。在一个太阳光照射下，PGE 在纯水中表现出卓越的太阳能蒸发性能，蒸发率达到 2.21 kg m-2 h-1，蒸发效率高达 98%。在海水和亚甲基蓝溶液等更复杂的介质中，PGE 也表现出卓越的蒸发能力，蒸发率分别达到 2.08 和 2.47 公斤米-2 小时-1。即使在酸性和碱性处理持续交替进行的情况下，PGE 仍能保持超过 2.0 kg m-2 h-1 的惊人蒸发率，再加上结构坚固，使其有望在极端环境中得到实际应用。
{"title":"Highly Efficient Porous Glass Solar Water Evaporator","authors":"Junsheng Liu, Wenqing Ruan, Heting Zhang, Jinbiao Huang, Jiahao Wang, Jianan Fu, Fei Sun, Lixing Zhu, Yangguang Zhan, Jiang Ma","doi":"10.1002/adfm.202415394","DOIUrl":"https://doi.org/10.1002/adfm.202415394","url":null,"abstract":"The global water crisis, exacerbated by excessive use and pollution, has resulted in energy scarcity and threats. Solar desalination provides a sustainable fix, with researchers developing photothermal materials and designs to improve efficiency and sustainability. Glass materials, with their exceptional chemical stability, are suitable for extreme desalination in acidic and alkaline conditions. In this work, we have developed a porous glass evaporator (PGE) with exceptional water evaporation efficiency, achieved through a novel fabrication method that blends glass powders with soluble salts to create structure with continuous pores. The evaporator's microstructure comprises micrometer-scale pores that form interconnected porous channels, facilitating efficient water transport and preventing salt deposition. Under one sun irradiation, the PGE exhibits superior solar evaporation performance in pure water, achieving a rate of 2.21 kg m<sup>−2</sup> h<sup>−1</sup>, with an evaporation efficiency of 98%. In more complex media, such as seawater and methylene blue solution, the PGE also displays excellent evaporation capabilities, reaching rates of 2.08 and 2.47 kg m<sup>−2</sup> h<sup>−1</sup>, respectively. Even after sustained alternation between acidic and alkaline treatments, the PGE retains an impressive evaporation rate of over 2.0 kg m<sup>−2</sup> h<sup>−1</sup>, coupled with structural robustness, making it a promising candidate for practical applications in extreme environments.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"95 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1038/s42256-024-00922-7
Sebastian Porsdam Mann, Anuraag A. Vazirani, Mateo Aboy, Brian D. Earp, Timo Minssen, I. Glenn Cohen, Julian Savulescu
In this Comment, we propose a cumulative set of three essential criteria for the ethical use of LLMs in academic writing, and present a statement that researchers can quote when submitting LLM-assisted manuscripts in order to testify to their adherence to them.
{"title":"Guidelines for ethical use and acknowledgement of large language models in academic writing","authors":"Sebastian Porsdam Mann, Anuraag A. Vazirani, Mateo Aboy, Brian D. Earp, Timo Minssen, I. Glenn Cohen, Julian Savulescu","doi":"10.1038/s42256-024-00922-7","DOIUrl":"https://doi.org/10.1038/s42256-024-00922-7","url":null,"abstract":"In this Comment, we propose a cumulative set of three essential criteria for the ethical use of LLMs in academic writing, and present a statement that researchers can quote when submitting LLM-assisted manuscripts in order to testify to their adherence to them.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"28 1","pages":""},"PeriodicalIF":23.8,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Saba Arash, Govinda Kharal, Bryan L. Chavez, Noah D. Ferson, Sara C. Mills, Jennifer S. Andrew, Thomas M. Crawford, Yanwen Wu
1D multiferroic fibers are known to exhibit attractive characteristics, including enhanced magnetoelectric (ME) coupling compared to thin film and bulk architectures. A comprehensive understanding of composite fibers, however, has been hindered by the complexity of their structure, leading to limited reports. Here, clear and strong ME coupling is experimentally detected in a composite Janus nanofiber aggregate using second harmonic generation (SHG) polarimetry under different magnetic field orientations. The observation of such a pronounced effect using an all-optical method has not been previously reported in multiferroic fibers. A series of global fits is performed to the SHG polarimetry results to investigate the behavior of nanofibers within an aggregate. We find the magnetically assembled fibers exhibit semi-cylindrical alignment as well as the expected lengthwise alignment despite variations in size and composition from fiber to fiber. The ME coupling and the semi-cylindrical alignment seen in SHG are further corroborated via X-ray diffraction under similar magnetic field conditions. These findings contribute to the development of complex composite and multifunctional devices using multiferroic nanostructures as building blocks, even those with inhomogeneous shapes and geometries.
众所周知，一维多铁氧体纤维表现出极具吸引力的特性，包括与薄膜和块体结构相比增强的磁电（ME）耦合。然而，对复合纤维的全面了解却因其结构的复杂性而受到阻碍，导致相关报道十分有限。在这里，利用二次谐波发生（SHG）极坐标测量法，在不同磁场方向下，在复合 Janus 纳米纤维聚合体中实验性地检测到了清晰而强烈的 ME 耦合。在多铁素体纤维中使用全光学方法观测到如此明显的效应，以前从未报道过。我们对 SHG 极坐标测量结果进行了一系列全局拟合，以研究聚合体中纳米纤维的行为。我们发现，尽管不同纤维的尺寸和成分存在差异，但磁性组装纤维表现出半圆柱排列以及预期的纵向排列。在类似的磁场条件下，X 射线衍射进一步证实了在 SHG 中看到的 ME 耦合和半圆柱排列。这些发现有助于开发以多铁性纳米结构为构件的复杂复合和多功能设备，即使是那些具有不均匀形状和几何结构的设备。
{"title":"Multiferroicity and Semi-Cylindrical Alignment in Janus Nanofiber Aggregates","authors":"Saba Arash, Govinda Kharal, Bryan L. Chavez, Noah D. Ferson, Sara C. Mills, Jennifer S. Andrew, Thomas M. Crawford, Yanwen Wu","doi":"10.1002/adfm.202412690","DOIUrl":"https://doi.org/10.1002/adfm.202412690","url":null,"abstract":"1D multiferroic fibers are known to exhibit attractive characteristics, including enhanced magnetoelectric (ME) coupling compared to thin film and bulk architectures. A comprehensive understanding of composite fibers, however, has been hindered by the complexity of their structure, leading to limited reports. Here, clear and strong ME coupling is experimentally detected in a composite Janus nanofiber aggregate using second harmonic generation (SHG) polarimetry under different magnetic field orientations. The observation of such a pronounced effect using an all-optical method has not been previously reported in multiferroic fibers. A series of global fits is performed to the SHG polarimetry results to investigate the behavior of nanofibers within an aggregate. We find the magnetically assembled fibers exhibit semi-cylindrical alignment as well as the expected lengthwise alignment despite variations in size and composition from fiber to fiber. The ME coupling and the semi-cylindrical alignment seen in SHG are further corroborated via X-ray diffraction under similar magnetic field conditions. These findings contribute to the development of complex composite and multifunctional devices using multiferroic nanostructures as building blocks, even those with inhomogeneous shapes and geometries.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"108 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anqi Liu, Qipeng Zhang, Lei Pan, Fan Yang, Dan Lin, Changlong Jiang
Electron donor–acceptor (D–A) molecules are emerging tools for designing sensitive luminogens, attracting significant research attention. However, due to poor quantum yields under certain conditions, current D–A fluorophores often suffer from fluorescence quenching in practical applications. Developing new D–A dyes and functional composites is crucial for expanding their applications. Here, a novel donor–acceptor type flavonoid dye molecule, namely “AFL”, exhibiting both polarity-dependent fluorescence emission wavelength shift and viscosity-dependent intensity change, for polarity measurement and temperature sensing is designed and synthesized. Because the intramolecular charge transfer (ICT) can be enhanced by a decrease of excited state energy caused in high-polarity organic solvents, AFL undergoes fluorescence emission wavelength shift that shows fluorescence color response to solvents of different polarities and hence differentiates between them. Moreover, the actual temperature can be monitored by the as-designed AFL@tetradecanoic acid (AFL@TA) sensor. By combining with TA, viscosity sensitively changes upon the temperature change of insoluble composites, thus realizing the fluorescence intensity response to temperature. Remarkable recyclable performance and satisfactory mechanical properties are integrated. This study provides a promising approach to developing a new D–A fluorescent probe and furnishes perspectives on the potential of such D–A type flavonoid material in stimuli-responsive systems with a focus on visualization sensing technology.
{"title":"Donor–Acceptor Type Solvatochromic Flavonoid Materials Fluorphores for Polarity Sensing and Real-Time Temperature Monitoring","authors":"Anqi Liu, Qipeng Zhang, Lei Pan, Fan Yang, Dan Lin, Changlong Jiang","doi":"10.1002/adfm.202415250","DOIUrl":"https://doi.org/10.1002/adfm.202415250","url":null,"abstract":"Electron donor–acceptor (D–A) molecules are emerging tools for designing sensitive luminogens, attracting significant research attention. However, due to poor quantum yields under certain conditions, current D–A fluorophores often suffer from fluorescence quenching in practical applications. Developing new D–A dyes and functional composites is crucial for expanding their applications. Here, a novel donor–acceptor type flavonoid dye molecule, namely “AFL”, exhibiting both polarity-dependent fluorescence emission wavelength shift and viscosity-dependent intensity change, for polarity measurement and temperature sensing is designed and synthesized. Because the intramolecular charge transfer (ICT) can be enhanced by a decrease of excited state energy caused in high-polarity organic solvents, AFL undergoes fluorescence emission wavelength shift that shows fluorescence color response to solvents of different polarities and hence differentiates between them. Moreover, the actual temperature can be monitored by the as-designed AFL@tetradecanoic acid (AFL@TA) sensor. By combining with TA, viscosity sensitively changes upon the temperature change of insoluble composites, thus realizing the fluorescence intensity response to temperature. Remarkable recyclable performance and satisfactory mechanical properties are integrated. This study provides a promising approach to developing a new D–A fluorescent probe and furnishes perspectives on the potential of such D–A type flavonoid material in stimuli-responsive systems with a focus on visualization sensing technology.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"29 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subi Choi, Hongye Guo, Bitgaram Kim, Ji-Hun Seo, Eugene M. Terentjev, Mohand O. Saed, Suk-kyun Ahn
Liquid crystal elastomers (LCEs) exhibit extraordinary energy dissipation due to their unique viscoelastic response, resulting from the rotation of mesogens under mechanical stress. While recent studies demonstrate the LCE-based pressure-sensitive adhesives (PSAs) by exploiting the enhanced damping, all previous studies have focused on LCEs with covalent crosslinks. Here, a new class of PSAs is developed by integrating movable polyrotaxane crosslinkers into an LCE matrix (PRx-LCEs). Dynamic viscoelastic measurements reveal that PRx-LCE exhibits a remarkably high energy dissipation, as indicated by a large tan δ. Interestingly, the secondary tan δ peak associated with LCE damping is more pronounced than the primary peak of the glass transition. The exceptional energy dissipation in PRx-LCE results in superior adhesion strength (≈1864 N m−1), which is 3.5 times higher than conventional LCEs and 13 times higher than commercial PSAs in the peel test. Additionally, PRx-LCEs demonstrate thermally reversible adhesion, enabling clean removal at elevated temperatures. Furthermore, the sliding effect in PRx-LCE enhances both deformability and stress relaxation under load, resulting in deeper indentation, and superior adhesion during the probe tack test. The combination of LCE and slidable crosslinks provides robust and switchable adhesion, making them promising for applications in biomedical engineering, display, and semiconductor industries.
液晶弹性体（LCE）因其独特的粘弹性响应而表现出非凡的能量耗散能力，这种响应是介质在机械应力作用下旋转产生的。最近的研究表明，基于液晶弹性体的压敏粘合剂（PSA）可以利用其增强的阻尼作用，但之前的研究都集中在具有共价交联的液晶弹性体上。本文通过在 LCE 基体（PRx-LCEs）中加入可移动的聚二十六烷交联剂，开发了一类新型压敏胶。动态粘弹性测量结果表明，PRx-LCE 具有极高的能量耗散能力，这体现在其具有较大的 tan δ 值。有趣的是，与 LCE 阻尼相关的 tan δ 次峰比玻璃化转变的主峰更为明显。PRx-LCE 卓越的能量耗散性能带来了超强的粘附强度（≈1864 N m-1），在剥离测试中比传统 LCE 高出 3.5 倍，比商用 PSAs 高出 13 倍。此外，PRx-LCE 还具有热可逆粘附性，可在高温下清洁去除。此外，PRx-LCE 中的滑动效应还能增强负载下的变形能力和应力松弛，从而使压痕更深，并在探针粘性测试中获得优异的粘附性。LCE 与可滑动交联的结合提供了稳健且可切换的粘附性，使其有望应用于生物医学工程、显示和半导体行业。
{"title":"Harnessing Extreme Internal Damping in Polyrotaxane-Incorporated Liquid Crystal Elastomers for Pressure-Sensitive Adhesives","authors":"Subi Choi, Hongye Guo, Bitgaram Kim, Ji-Hun Seo, Eugene M. Terentjev, Mohand O. Saed, Suk-kyun Ahn","doi":"10.1002/adfm.202413824","DOIUrl":"https://doi.org/10.1002/adfm.202413824","url":null,"abstract":"Liquid crystal elastomers (LCEs) exhibit extraordinary energy dissipation due to their unique viscoelastic response, resulting from the rotation of mesogens under mechanical stress. While recent studies demonstrate the LCE-based pressure-sensitive adhesives (PSAs) by exploiting the enhanced damping, all previous studies have focused on LCEs with covalent crosslinks. Here, a new class of PSAs is developed by integrating movable polyrotaxane crosslinkers into an LCE matrix (PRx-LCEs). Dynamic viscoelastic measurements reveal that PRx-LCE exhibits a remarkably high energy dissipation, as indicated by a large tan δ. Interestingly, the secondary tan δ peak associated with LCE damping is more pronounced than the primary peak of the glass transition. The exceptional energy dissipation in PRx-LCE results in superior adhesion strength (≈1864 N m<sup>−1</sup>), which is 3.5 times higher than conventional LCEs and 13 times higher than commercial PSAs in the peel test. Additionally, PRx-LCEs demonstrate thermally reversible adhesion, enabling clean removal at elevated temperatures. Furthermore, the sliding effect in PRx-LCE enhances both deformability and stress relaxation under load, resulting in deeper indentation, and superior adhesion during the probe tack test. The combination of LCE and slidable crosslinks provides robust and switchable adhesion, making them promising for applications in biomedical engineering, display, and semiconductor industries.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"95 1","pages":""},"PeriodicalIF":19.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142602029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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