Gram‐Scale Production of Iron Oxide Rubik‐Cube Nanoparticles: New Tools for the Clinical Translation of Magnetic Hyperthermia and Magnetic Particle ImagingRizzo, Giusy M. R.; Silvestri, Niccolò; Jarmouni, Nabila; Gavilán, Helena; Yakubu, Hamza; Arenas‐Esteban, Daniel; Bals, Sara; Parlanti, Paola; Gemmi, Mauro; Prado, Ross Clark; Samia, Anna Cristina S.; Salgueiriño, Verónica; Pellegrino, Teresa
doi: 10.1002/adfm.202522732pmid: N/A
This work presents the first gram‐scale solvothermal synthesis of a novel class of anisotropic nanoparticles with a distinctive architecture, termed “Rubik's cube nanoparticles.” These nanostructures combine an overall cubic morphology with a dendritic multi‐core structure, resulting in a unique morphology with record magnetic heating performance. Their formation is achieved by a carefully engineered mixture of shape‐directing agents, including a subclass of vinyl ketones and aromatic aldehydes. By adjusting the ketone/iron molar ratio or the reaction time, the nanoparticle size was tuned between 19 and 45 nm. Structural characterization confirms their single domain nature and identifies the Ƴ‐Fe2O3 magnetic phase with cubic structure (space group Fd‐3m). Despite their large size, they exhibit low coercivity with high saturation magnetization, leading to record magnetic heat losses under clinically relevant radiofrequency excitation. Furthermore, Rubik's cube nanoparticles up to 27 nm show a medium viscosity‐independent magnetic heat efficiency. Particles with edge lengths of 27 and 42 nm exhibit enhanced performance in magnetic particle imaging compared to VivoTrax standard. Furthermore, the application of a magnetic field gradient during magnetic hyperthermia allows for spatial localization of heat generation. These properties position Rubik's cube nanoparticles as promising candidates for clinical translation with therapeutic efficacy and diagnostic precision in oncology.
Enhanced MHz Magnetic Properties of Easy‐Plane FeSi3.5 Soft Magnetic Composites via Acid Etching‐Induced Dual CoatingYang, Liaoliao; Wu, Peng; Luo, Jiahui; Wang, Qi; Qiao, Liang; Li, Fashen
doi: 10.1002/adfm.202523393pmid: N/A
Easy‐plane soft magnetic composites (SMCs) have been proven to be a type of soft magnetic material that is highly likely to be matched with the high‐frequency operating conditions of third‐generation semiconductors. In this study, FeSi3.5 easy‐plane powders are surface‐modified with phosphoric acid and subsequently subjected to annealing. This process successfully synthesizes easy‐plane FeSi3.5 powders featuring a dual‐layer coating. Furthermore, the formation of the Fe2(SiO3)3 layer not only suppresses excessive corrosion of FeSi3.5 by phosphoric acid but also reduces lattice mismatch between the substrate and the outer coating layer. Based on Bertotti's classical theory, the results indicate that this process provides excellent insulation while facilitating the release of internal strain and lowering defect concentration resulting in a significant reduction in hysteresis loss and eddy current loss. Hysteresis loss and eddy current loss decrease from 3404.1 to 2362 kW m−3 and from 414.1 to 89.4 kW m−3 at 20 mT, 5 MHz, respectively. This study develops a novel method for soft magnetic material design by acid etching and annealing process to construct a dual‐coating, thereby further optimizing the comprehensive magnetic properties of FeSi3.5 easy‐plane SMCs.
Switchable Thermal Mid‐IR Conducting Polymer Antenna ArraysBandaru, Pravallika; Ansari, Mohammad Shaad; Kazi, Suraya; Lin, Dongqing; Polyakov, Alexander Yu; Jonsson, Magnus P.
doi: 10.1002/adfm.202525508pmid: N/A
While initial studies on conducting polymer plasmonic antennas have focused on the near‐infrared spectral range, their reversible plasmonic‐dielectric switchability presents significant potential also for the mid‐infrared (mid‐IR) ≈10 µm which is relevant for the control of thermal emission at room temperature. Here, the applicability of conducting polymers is extended to tunable thermal mid‐IR applications. The study demonstrates scalable fabrication of poly(3,4‐ethylenedioxythiophene:tosylate) (PEDOT:Tos) microantenna arrays through photolithography and provides a systematic size and shape investigation using electron‐beam lithography. The polymeric microantenna arrays show clear asymmetric Fano‐type mid‐IR resonances which are spectrally tunable in the thermal range from 6 to 12 µm via the size, periodicity and shape of the antennas. The optical response of the antenna arrays is reversibly switched “OFF” and “ON” by tuning the polaronic charge carrier concentration in the antennas via the polymer's redox state. The results open new routes to dynamically control mid‐IR thermal emission, with potential applications including beam steering, adaptive camouflage and tunable radiative cooling.
Fluoride‐Free Adhesives for Low Surface Energy Fluorinated SubstratesZheng, Siqi; Sheng, Yifeng; Tan, Shiqian; Sun, Yuxuan; Li, Linling; Zhu, He; Zhang, Qi; Zhu, Shiping
doi: 10.1002/adfm.202523689pmid: N/A
Designing high‐performance adhesives for fluorinated substrates, such as polytetrafluoroethylene (PTFE), remains a persistent challenge due to their ultra‐low surface energy and chemical inertness. Traditionally, strong adhesion to these surfaces has relied on fluorinated additives and per‐ and polyfluoroalkyl substances (PFAS), raising serious environmental and health concerns due to their persistence and toxicity. In response to increasing regulatory scrutiny and the rising demand for sustainable materials, a universal, fluoride‐free adhesive strategy based on copolymers featuring tertiary amine and amide functionalities is introduced. By leveraging strong dipole–dipole interactions afforded by carefully selected polar monomers, robust interfacial adhesion is achieved without the use of fluorinated components. The optimized copolymers, synthesized from 2‐(diisopropylamino)ethyl methacrylate and N,N‐dimethylacrylamide, demonstrate a record lap shear strength of 4.91 MPa on PTFE, significantly surpassing both commercial adhesives and previously reported systems. This work not only establishes a versatile and effective platform for fluoride‐free adhesion to challenging substrates but also advances the field toward next‐generation, environmentally responsible adhesive technologies.
Atomically Precise Bottom‐Up Growth of Semiconducting Te NanoribbonsGao, Wenjin; Hua, Chenqiang; Zheng, Qiao; Dou, Wenzhen; Yu, Pengfei; Zhu, Yinuo; Zhou, Miao; Niu, Tianchao
doi: 10.1002/adfm.202523222pmid: N/A
The synthesis of semiconducting nanoribbons with atomic precision remains a formidable challenge, yet is critical for future downscaling of advanced logic and memory devices. Here, the successful epitaxial growth of atomically precise Te nanoribbons via a buffer‐layer engineering strategy on Cu(111) is demonstrated. An ultraflat blue phosphorene monolayer is first introduced onto the Cu surface to suppress the direct Cu─Te interfacial alloying. Subsequent Te deposition cleaves P─P bonds, inducing the generation of Cu2Te2 with periodic trenches atop a Cu2P phase. This template guides the self‐assembly of Te into ordered arrays of three‐atom‐wide zigzag nanoribbons. Scanning tunneling microscopy/spectroscopy and density functional theory calculations reveal a semiconducting 1T‐MoS2‐like structure with a bandgap of 0.51 eV and a mobility of ≈1000 cm2 V−1 s−1. Given the versatility of this buffer layer control strategy, it can establish a general paradigm for the precise synthesis of monoelemental nanoribbon structures with tailored chemical and electronic properties.
Tuning Fe2+ Release Kinetics via Coordination Engineering Toward Highly Stable Prussian Blue Analogs with Enhanced K+ StorageYue, Lijuan; Li, Qingze; Duan, Yan; Gao, Peng; Xiao, Peitao; Wang, Zixing; Liu, Jilei
doi: 10.1002/adfm.202524076pmid: N/A
Prussian blue analogs (PBAs) are promising cathode materials for potassium‐ion batteries (PIBs) due to their low cost and open framework that facilitates rapid ion transport. However, severe performance degradation upon cycling arises from structural defects that impedes the practical implementation of PBAs‐based PIBs. Herein, a dual‐chelating agent co‐precipitation strategy is proposed to synthesize potassium‐rich PBAs. By modulating the potassium citrate (KCA) to dipotassium ethylenediaminetetraacetate (EDTA‐2K) ratio, the strategy precisely controls the coordination environment during co‐precipitation, regulates Fe2+ release kinetics, and ultimately yields K1.7Fe[Fe(CN)6]0.83·◻0.17·0.73H2O (KCA75) material with high reversible potassium content (1.7 mol−1) and low coordinated water content (4.7 wt.%). In situ Raman analysis demonstrates that the controlled Fe2+ release kinetics effectively suppress the formation of [Fe(CN)6]4− vacancies and minimize water incorporation. Consequently, the optimized KCA75 cathode delivers a reversible capacity of 128 mAh g−1 at 0.2C, exceptional rate capability (65 mAh g−1 even at 10C), and extended cycling stability (94.8% capacity retention ratio after 1000 cycles at 5C). The KCA75//graphite full cell demonstrates remarkable cycling stability, maintaining 92.7% capacity retention over 1 000 cycles. These findings underscore the potential of PBAs as PIBs cathodes and highlight the critical role of Fe2+ release kinetics regulation through coordination engineering in optimizing PBAs structural integrity.