Nanocrystalline Domains Research Articles

Super-Tough, Non-Swelling Zwitterionic Hydrogel Sensor Based on the Hofmeister Effect for Potential Motion Monitoring of Marine Animals.

Hydrogel-based electronic devices in aquatic environments have sparked widespread research interest. Nevertheless, the challenge of developing hydrogel electronics underwater has not been profoundly surmounted because of the fragility and swelling of hydrogels in aquatic environments. In this work, a zwitterionic double network hydrogel comprisedof polyvinyl alcohol (PVA), poly(sulfobetaine methacrylate) (PSBMA), and sulfuric acid (H2SO4) demonstrates super-tough and non-swelling performance. The Hofmeister effect of H2SO4 and PSBMA induces the PVA chains to form numerous nanocrystalline domains, which serve as the primary physical crosslinking points and provide effective energy dissipation. H2SO4 induces a strong salting-out effect to facilitate PVA crystallization and the formation of a dense and stable network structure that inhibits swelling. The resulting hydrogel exhibits an ultra-high toughness of 4.61MJm-3, non-swelling, and long-term stability for up to a month in pure water and seawater. Based on this, a hydrogel-based seawater strain sensor has been developed to monitor the underwater movements of marine animal models. Reliable and stable sensing performance ensures real-time collection of underwater motion signals, despite the impacts of water flow and the interference of ions. This study provides a facile approach to designing super-tough and non-swelling hydrogels and further expands the application of underwater electronic devices.

Nanomineralogy of thorite in the supergiant Huayangchuan uranium ore deposit: Revealing a new geochemical behavior of actinide in environment

Thorium (Th) is a naturally occurring radioactive element found in the environment, and recent advancements have been made in identifying and characterizing Th-bearing nanoparticles (NPs). However, the main focus is still on synthesized Th-bearing NPs and knowledge about natural Th-bearing NPs remains limited. Here, high-resolution transmission electron microscopy (HRTEM) observations of thorite from the Huayangchuan uranium ore deposit in Shaanxi Province, Central China, have revealed the nanoscale mineral characteristics of thorite. In this study, thorite NPs ranging from 5–10 nm in size were identified within the uranium ore. A combination of transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) elemental mapping and corresponding HRTEM images alongside Selected Area Electron Diffraction (SAED) and Fast Fourier Transform (FFT) patterns revealed a complex nanoscale structure in the thorite NPs, consisting of both amorphous and crystalline nanodomains with abundant defects. These nanostructures are associated with a metamictization mechanism in micrometer-sized thorite. Our findings indicate that the metamictization process can generate numerous thorite nanoparticles. Given the high penetrability and mobility of these NPs, the metamictization of thorite poses new challenges for the long-term stability of radioactive substances and the storage containers for radioactive waste. Furthermore, considering the likelihood of environmental release and the chemical toxicity, radioactivity, and nanotoxicity of natural Th-bearing NPs, increased attention should be given to the presence of natural thorite NPs in the ore deposit.

Multifunctional Nano‐Conductive Hydrogels With High Mechanical Strength, Toughness and Fatigue Resistance as Self‐Powered Wearable Sensors and Deep Learning‐Assisted Recognition System

AbstractHigh mechanical strength, toughness, and fatigue resistance are essential to improve the reliability of conductive hydrogels for self‐powered sensing. However, achieving mutually exclusive properties simultaneously remains challenging. Hence, a novel directed interlocking strategy based on topological network structure and mechanical training is proposed to construct tough hydrogels by optimizing the network structure and modulating the orientation of molecular chains. Combining Zn2+ crosslinked cellulose nanofibers (CNFs) and a polyacrylamide‐poly(vinyl alcohol) double‐network, the unique interlocked‐network structure exhibits an enhanced toughening effect due to hydrogen bonding and metal‐ligand interactions. The aligned nanocrystalline domains achieved by training further contribute to an increase in the toughness and fatigue thresholds. This innovative approach synergistically enhances the mechanical properties of the nano‐conductive hydrogel, achieving a maximum tensile strength of 4.98 MPa and a toughness of 48 MJ m−3. Notably, the CNFs template with anchored polyaniline, when oriented through mechanical training, forms a unique directional conductive pathway, which significantly enhances the power output performance. Besides, a motion recognition system based on a self‐powered sensing device is designed with the assistance of deep learning techniques to accurately identify human motion behaviors. This work showcases a potentially transformative flexible electronic material for self‐powered sensing systems and intelligent recognition systems.

Interactions of polychlorinated cyclodiene pesticides with model fungal membranes – Langmuir monolayer and liposome studies

Polychlorinated cyclodiene pesticides (CP) are persistent organic pollutants causing widespread soil contamination. CPs-contaminated soils could be purified by mycoremediation, i.e. the introduction of CP-degrading fungal strains into the soils. However, not all mycoremediation attempts are effective, and the microbial cells introduced into the soil die. CP molecules are highly hydrophobic, therefore, their toxicity may largely result from membrane activity, i.e. from the incorporation of CP molecules into membranes disturbing their functions. To test this hypothesis and shed light on the interactions of CPs with plasma membranes, we used lipid Langmuir monolayers and unilamellar liposomes as models of fungal membranes. In our research, we included the four most common CPs polluting soils: aldrin, endrin, endosulfan, and chlordecone. Our studies have shown that CPs can be incorporated into the membranes up to the molar ratio of approximately 0.15. In the case of Langmuir monolayers, greater effects were observed for the model composed of saturated lipids. For this model, however, X-ray diffraction studies have shown that CPs are incorporated into the ergosterol-enriched amorphous phase without disturbing the formation of crystalline phospholipid nanodomains. Langmuir monolayer studies showed that chlordecone disturbs the physical properties of the model membrane to the greatest extent. However, liposome studies have shown that the effect of all CPs is similar – their presence increases the fluidity of the bilayer. Our studies confirmed CPs’ membrane activity, however, also showed that the presence of CP molecules in lipid membranes does not cause drastic changes in their physical properties.

Tailoring MoS2 domains size, doping, and light emission by the sulfurization temperature of ultra-thin MoOx films on sapphire

Thermal sulfurization of ultra-thin Mo-based films represents a promising approach for large-area growth of MoS2. In this paper, we demonstrated that the crystalline quality (domains size and defects density), strain, doping, and light emission properties of monolayer (1L) MoS2 obtained from sputter deposited MoOx films on a c-sapphire substrate can be tailored by the sulfurization temperature (Ts) in the range from 700 to 800 °C. Starting from a continuous film with a nanocrystalline domains structure at Ts = 700 °C, a distribution of 1L MoS2 triangular domains with 2.1 ± 0.6 and 2.6 ± 1.6 μm average sizes was obtained by increasing Ts to 750 and 800 °C, respectively. The increase in Ts was accompanied by a strong (25×) enhancement of the photoluminescence (PL) intensity. Furthermore, the average doping of MoS2, evaluated from Raman analyses, evolved from a strong p-type doping (∼1 × 1013 cm−2) after Ts = 700 °C, ascribed to residual MoO3 in the film, to a low average n-type doping (∼0.04 × 1013 cm−2) after Ts = 800 °C. The wide tunability of doping and PL of 1L MoS2 by the sulfurization temperature can be exploited to tailor material properties for different specific applications.

Molecular-Induced Steric Shape Separation of Nano Geometries

The separation of specific-shaped nanoparticles from particle mixtures is important for the construction of particle domains with shape-specific characteristics. On the other hand, shape-based particle separation techniques have not received as much attention as size-based techniques. The shape separation effect of molecule-coated nanoparticles is primarily dependent on short-range steric interaction. The surfactant’s geometrical arrangement determines the position of the nanoparticle’s various crystallographic facets; this also determines how the various shapes are organized throughout the nanoparticle self-assembly process. In addition to smooth surfaces with a fixed droplet contact line and a stable environment, the self-assembled shape separation effect has been observed on surfaces with wettability stripe patterns and fluctuating environments where the droplet contact line behaves stick–slip-like during the evaporation process. The shape separation of spheres and rods is strongly influenced by steric interactions. Since shape-dependent transport properties exist in such nano-crystalline domains, it is important to understand the shape separation effect.

Biomimetic Mechanically Robust Chiroptical Hydrogel Enabled by Hierarchical Bouligand Structure Engineering.

Natural bouligand structures enable crustacean exoskeletons and fruits to strike a combination of exceptional mechanical robustness and brilliant chiroptical properties owing to multiscale structural hierarchy. However, integrating such a high strength-stiffness-toughness combination and photonic functionalities into synthetic hydrogels still remains a grand challenge. In this work, we report a simple yet general biomimetic strategy to construct an ultrarobust chiroptical hydrogel by closely mimicking the natural bouligand structure at multilength scale. The hierarchical structural engineering of long-range ordered cellulose nanocrystals' bouligand structure, well-defined poly(vinyl alcohol) nanocrystalline domains, and dynamic interfacial interaction synergistically contributes to the integration of high strength (23.3 MPa), superior modulus (264 MPa), and high toughness (54.7 MJ m-3), as well as extraordinary impact resistance, which far exceed their natural counterparts and synthetic photonic hydrogels. More importantly, seamless chiroptical and solvent-responsive patterns with high resolution can also be scalably integrated into the hydrogel by localized manipulation of the photonic band, while maintaining good ionic conductivity. Such exceptional mechanical-photonic combination holds tremendous potential for applications in wearable sensors, encryption, displays, and soft robotics.

Structure-Dependent Water Responsiveness of Protein Block Copolymers.

Biological water-responsive (WR) materials are abundant in nature, and they are used as mechanical actuators for seed dispersal by many plants such as wheat awns and pinecones. WR biomaterials are of interest for applications as high-energy actuators, which can be useful in soft robotics or for capturing energy from natural water evaporation. Recent work on WR silk proteins has shown that β-sheet nanocrystalline domains with high stiffness correlate with the high WR actuation energy density, but the fundamental mechanisms to drive water responsiveness in proteins remain poorly understood. Here, we design, synthesize, and study protein block copolymers consisting of two α-helical domains derived from cartilage oligomeric matrix protein coiled-coil (C) flanking an elastin-like peptide domain (E), namely, CEC. We use these protein materials to create WR actuators with energy densities that outperform mammalian muscle. To elucidate the effect of structure on WR actuation, CEC was compared to a variant, CECL44A, in which a point mutation disrupts the α-helical structure of the C domain. Surprisingly, CECL44A outperformed CEC, showing higher energy density and less susceptibility to degradation after repeated cycling. We show that CECL44A exhibits a higher degree of intermolecular interactions and is stiffer than CEC at high relative humidity (RH), allowing for less energy dissipation during water responsiveness. These results suggest that strong intermolecular interactions and the resulting, relatively steady protein structure are important for water responsiveness.

Mechanical Properties of an Ultrahard In Situ Amorphous Steel Matrix Composite

We report compression tests on micropillars manufactured from bulk specimens of partially devitrified SAM2×5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4). Yield strength values of ≈6 GPa are obtained. Such a high strength can be attributed to the higher glass transition temperature (883 K) of this material, which impedes the multiplication of shear bands under loading, and to the presence of hard crystalline domains that result from devitrification of the amorphous powders during powder consolidation. The Vickers hardness of the specimens is found to be strongly correlated to the processing temperature and, hence to the volume of crystalline phases present in the specimens. As the processing temperature is increased, there is a reduction in free volume from the structural relaxation process in the amorphous alloy, leading to the eventual nucleation of crystalline phases of BCC Fe, Cr2B, Cr21.30Fe1.7C6, or Fe23B2C4, during the densification process. These results shed light on the relationship between nanocrystalline domains and the mechanical behavior of Fe‐based amorphous/crystalline composites.

Durable Ru Nanocrystal with HfO2 Modification for Acidic Overall Water Splitting

HighlightsHeterostructure constructed via confining crystalline ruthenium nanodomains by hafnium dioxide matrix was fabricated through a two-step annealing method for overall water splitting.The synergistic effect of hafnium dioxide modification and small crystalline domain formation significantly alleviates the over-oxidation of ruthenium.

Simultaneously Boosting Thermoelectric and Mechanical Properties of n-Type Mg3Sb1.5Bi0.5-Based Zintls through Energy-Band and Defect Engineering.

Incorporating donor doping into Mg3Sb1.5Bi0.5 to achieve n-type conductivity is one of the crucial strategies for performance enhancement. In pursuit of higher thermoelectric performance, we herein report co-doping with Te and Y to optimize the thermoelectric properties of Mg3Sb1.5Bi0.5, achieving a peak ZT exceeding 1.7 at 703 K in Y0.01Mg3.19Sb1.5Bi0.47Te0.03. Guided by first-principles calculations for compositional design, we find that Te-doping shifts the Fermi level into the conduction band, resulting in n-type semiconductor behavior, while Y-doping further shifts the Fermi level into the conduction band and reduces the bandgap, leading to enhanced thermoelectric performance with a power factor as high as >20 μW cm-1 K-2. Additionally, through detailed micro/nanostructure characterizations, we discover that Te and Y co-doping induces dense crystal and lattice defects, including local lattice distortions and strains caused by point defects, and densely distributed grain boundaries between nanocrystalline domains. These defects efficiently scatter phonons of various wavelengths, resulting in a low thermal conductivity of 0.83 W m-1 K-1 and ultimately achieving a high ZT. Furthermore, the dense lattice defects induced by co-doping can further strengthen the mechanical performance, which is crucial for its service in devices. This work provides guidance for the composition and structure design of thermoelectric materials.

On the structural evolution of nanoporous optically transparent CuO photocathodes upon calcination for photoelectrochemical applications.

Copper oxides are promising photocathode materials for solar hydrogen production due to their narrow optical band gap energy allowing broad visible light absorption. However, they suffer from severe photocorrosion upon illumination, mainly due to copper reduction. Nanostructuring has been proven to enhance the photoresponse of CuO photocathodes; however, there is a lack of precise structural control on the nanoscale upon sol-gel synthesis and calcination for achieving optically transparent CuO thin film photoabsorbers. In this study, nanoporous and nanocrystalline CuO networks were prepared by a soft-templating and dip-coating method utilizing poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic® F-127) as a structure-directing agent, resulting for the first-time in uniformly structured, crack-free, and optically transparent CuO thin films. The photoelectrochemical properties of the nanoporous CuO frameworks were investigated as a function of the calcination temperature and film thickness, revealing important information about the photocurrent, photostability, and photovoltage. Based on surface photovoltage spectroscopy (SPV), the films are p-type and generate up to 60 mV photovoltage at 2.0 eV (0.050 mW cm-2) irradiation for the film annealed at 750 °C. For these high annealing temperatures, the nanocrystalline domains in the thin film structure are more developed, resulting in improved electronic quality. In aqueous electrolytes with or without methyl viologen (as a fast electron acceptor), CuO films show cathodic photocurrents of up to -2.4 mA cm-2 at 0.32 V vs. RHE (air mass (AM) 1.5). However, the photocurrents were found to be entirely due to photocorrosion of the films and decay to near zero over the course of 20 min under AM 1.5 illumination. These fundamental results on the structural and morphological development upon calcination provide a direction and show the necessity for further (surface) treatment of sol-gel derived CuO photocathodes for photoelectrochemical applications. The study demonstrates how to control the size of nanopores starting from mesopore formation at 400 °C to the evolution of macroporous frameworks at 750 °C.

Solution-Processed Non-Crystalline Solid Electrolytes for Advanced Energy Storage

Advanced batteries containing a Li metal anode (LMA) are needed to enable the clean economy and meet ambitious climate targets. Currently, LMA batteries are limited by dendrite propagation due to the non-uniform plating and stripping of Li, which is detrimental to cell performance. The non-crystalline solid electrolyte (SE), lithium phosphorus oxynitride (LiPON) is unique in demonstrating stable Li plating/stripping at appreciable rates, but its synthesis requires costly and slow vacuum deposition methods. We use aqueous precursor solutions which are rapidly condensed during spin coating and gently annealed to produce dense, flat, Li metal oxide films without long-range order. However, such solution-processed SEs typically exhibit ionic conductivities (σ ion ) too low for energy storage applications (~10-8 S cm-1) and far lower than vacuum-deposited LiPON (~10-6 S cm-1).We will discuss various approaches to increase the σion of these materials, including compositional engineering and controlled processing conditions. Structure-property relationships have been elucidated using modelling of the local structure and interphase formation against Li evaluated by time-dependent electrochemical impedance spectroscopy and in situ X-ray photoelectron spectroscopy. Electrochemical testing of these films deposited onto a current collector in an anode-free cell will be used to evaluate their ability to facilitate stable deposition and stripping of Li.Initial exploration of processing parameters have yielded σion values > 10-7 S cm-1 [1] and the presence of medium-range order (nanocrystalline domains) in some cases. Beyond Li, new non-crystalline SEs for other ions will be discussed. As only limited chemical compositions and processing conditions of these materials have been reported, with no corresponding structural studies, our work provides insight to enable the optimisation and discovery of scalable non-crystalline SEs for advanced batteries.1. P. Vadhva, T. Gill, J. H. Cruddos, S. Said, M. Siniscalchi, S. Narayanan, M. Pasta, T.S. Miller, A.J.E. Rettie. Engineering solution-processed non-crystalline solid electrolytes for Li metal batteries. Chemistry of Materials, 2022, 35, 3, 1168–1176.

Highly Robust Conductive Organo-Hydrogels with Powerful Sensing Capabilities Under Large Mechanical Stress.

The low mechanical strength of conductive hydrogels (<1MPa) has been a significant hurdle in their practical application, as they are prone to fracturing under complex conditions, limiting their effectiveness. Here, this work fabricates a strong and tough conductive hierarchical poly(vinyl alcohol) (PEDOT:PSS/PVA) organo-hydrogel (PPS organo-hydrogel) via a facile combining strategy of self-assembly and stretch training. With PVA/PEDOT:PSS microlayers and aligned PVA/PEDOT:PSS nanofibers, PVA and PEDOT:PSS nanocrystalline domains, and semi-interpenetrating polymer networks, PPS organo-hydrogels display outstanding mechanical performances (strength: 54.8MPa, toughness: 153.97MJ m-3 ). Additionally, PPS organo-hydrogels also exhibit powerful sensing capabilities (gauge factor (GF): 983) due to the aligned hierarchical structures and organic liquid phase of DMSO. Notably, with the synergy of such mechanical and sensing properties, organo-hydrogels can even detect objects as light as 1 gram, despite bearing a tensile strength of ≈23MPa. By incorporating these materials into human-machine interfaces, such as controlling artificial arms for grabbing objects and monitoring sport behaviors in soccer training, this work has unlocked a new realm of possibilities for these high-performance hierarchical organo-hydrogels. This approach to designing hierarchical structures has the potential to lead to even more high-performance hydrogels in the future.

Fatigue-resistant hydrogel optical fibers enable peripheral nerve optogenetics during locomotion.

We develop soft and stretchable fatigue-resistant hydrogel optical fibers that enable optogenetic modulation of peripheral nerves in naturally behaving animals during persistent locomotion. The formation of polymeric nanocrystalline domains within the hydrogels yields fibers with low optical losses of 1.07 dB cm-1, Young's modulus of 1.6 MPa, stretchability of 200% and fatigue strength of 1.4 MPa against 30,000 stretch cycles. The hydrogel fibers permitted light delivery to the sciatic nerve, optogenetically activating hindlimb muscles in Thy1::ChR2 mice during 6-week voluntary wheel running assays while experiencing repeated deformation. The fibers additionally enabled optical inhibition of pain hypersensitivity in an inflammatory model in TRPV1::NpHR mice over an 8-week period. Our hydrogel fibers offer a motion-adaptable and robust solution to peripheral nerve optogenetics, facilitating the investigation of somatosensation.

Mechanically-Compliant Bioelectronic Interfaces through Fatigue-Resistant Conducting Polymer Hydrogel Coating.

Because of their distinct electrochemical and mechanical properties, conducting polymer hydrogels have been widely exploited as soft, wet, and conducting coatings for conventional metallic electrodes, providing mechanically compliant interfaces and mitigating foreign body responses. However, the long-term viability of these hydrogel coatings is hindered by concerns regarding fatigue crack propagation and/or delamination caused by repetitive volumetric expansion/shrinkage during long-term electrical interfacing. This study reports a general yet reliable approach to achieving a fatigue-resistant conducting polymer hydrogel coating on conventional metallic bioelectrodes by engineering nanocrystalline domains at the interface between the hydrogel and metallic substrates. It demonstrates the efficacy of this robust, biocompatible, and fatigue-resistant conducting hydrogel coating in cardiac pacing, showcasing its ability to effectively reduce the pacing threshold voltage and enhance the long-term reliability of electric stimulation. This study findings highlight the potential of its approach as a promising design and fabrication strategy for the next generation of seamless bioelectronicinterfaces.

Plasmonic Nanodomains Decorated on Two-Dimensional Oxide Semiconductors for Photonic-Assisted CO2 Conversion.

Plasmonic nanostructures ensure the reception and harvesting of visible lights for novel photonic applications. In this area, plasmonic crystalline nanodomains decorated on the surface of two-dimensional (2D) semiconductor materials represent a new class of hybrid nanostructures. These plasmonic nanodomains activate supplementary mechanisms at material heterointerfaces, enabling the transfer of photogenerated charge carriers from plasmonic antennae into adjacent 2D semiconductors and therefore activate a wide range of visible-light assisted applications. Here, the controlled growth of crystalline plasmonic nanodomains on 2D Ga2O3 nanosheets was achieved by sonochemical-assisted synthesis. In this technique, Ag and Se nanodomains grew on 2D surface oxide films of gallium-based alloy. The multiple contribution of plasmonic nanodomains enabled the visible-light-assisted hot-electron generation at 2D plasmonic hybrid interfaces, and therefore considerably altered the photonic properties of the 2D Ga2O3 nanosheets. Specifically, the multiple contribution of semiconductor-plasmonic hybrid 2D heterointerfaces enabled efficient CO2 conversion through combined photocatalysis and triboelectric-activated catalysis. The solar-powered acoustic-activated conversion approach of the present study enabled us to achieve the CO2 conversion efficiency of more than 94% in the reaction chambers containing 2D Ga2O3-Ag nanosheets.

Crystalline Nanodomains at Multifunctional Two-Dimensional Liquid–Metal Hybrid Interfaces

Two-dimensional (2D) liquid–metal (LM) heterointerfaces with their tunable physicochemical characteristics are emerging platforms for the development of multifunctional hybrid nanostructures with numerous functional applications. From this perspective, the functionalization of LM galinstan nanoparticles (NPs) with crystalline nanodomains is a promising approach toward the synthesis of novel 2D hybrid LM heterointerfaces with unprecedented properties. However, the decoration of LM heterointerfaces with desired nanocrystalline structures is a challenging process due to simultaneous and intensive interactions between liquid–metal-based structures and metallic nanodomains. The present study discloses a facile and functional method for the growth of crystalline nanodomains at LM heterointerfaces. In this sonochemical-assisted synthesis method, acoustic waves provide the driving force for the growth of ultra-fine crystalline nanodomains on the surface of galinstan NPs. The galinstan NPs were initially engulfed within carbon nanotube (CNT) frameworks, to prevent intensive reactions with surrounding environment. These CNT frameworks furthermore separate galinstan NPs from the other products of sonochemistry reactions. The following material characterization studies demonstrated the nucleation and growth of various types of polycrystalline structures, including Ag, Se, and Nb nanodomains on 2D heterointerfaces of galinstan NPs. The functionalized galinstan NPs showed tunable electronic and photonic characteristics originated from their 2D hybrid interfaces.

Quenching-induced surface reconstruction of perovskite oxide for rapid and durable oxygen catalysise

Rapid degradation of catalytic activity for oxygen reduction reaction has become key factor in restricting practical applications of perovskite oxide in solid oxide fuel cells. Herein, quenching is disclosed to be an effective method to bring rapid and durable oxygen catalysis of perovskite-structured Pr0.5Ba0.25Ca0.25CoO3-δ. The quenching processing, cooling rate is around 8000 times higher than that of traditional annealing process, could turn the output power density of single cells from the decay process with a rate of 17.1% into an upsurge process with a rate of 18.4%, resulting in a stable power density of 0.72 W cm−2. This relates to a large number of point defects, dislocations, disorder and nanocrystalline domains are formed in perovskite oxides by quenching. These chemical defects can drive cationic diffusion to the surface indiscriminately, forming electroactive perovskite-structured nanoparticles. This work provides a new technology and concept to optimize the performance of perovskite-structured oxygen catalysts.

Crystalline Magnetic Gels and Aerogels Combining Large Surface Areas and Magnetic Moments.

The production of materials that simultaneously combine large surface areas and high crystallinities is a major challenge. Conventional sol-gel chemistry strategies to produce high-surface-area gels and aerogels generally result in amorphous or poorly crystalline materials. To attain proper crystallinities, materials are exposed to relatively high annealing temperatures that result in significant surface losses. This is a particularly limiting issue in the production of high-surface-area magnetic aerogels owing to the strong relationship between crystallinity and magnetic moment. To overcome this limitation, we demonstrate here the gelation of preformed magnetic crystalline nanodomains to produce magnetic aerogels with high surface area, crystallinity, and magnetic moment. To exemplify this strategy, we use colloidal maghemite nanocrystals as gel building blocks and an epoxide group as the gelation agent. After drying from supercritical CO2, aerogels show surface areas close to 200 m2 g-1 and a well-defined maghemite crystal structure that provides saturation magnetizations close to 60 emu g-1. For comparison, the gelation of hydrated iron chloride with propylene oxide provides amorphous iron oxide gels with slightly larger surface areas, 225 m2 g-1, but very low magnetization, below 2 emu g-1. Thermal treatment at 400 °C is necessary to crystallize the material, which results in a surface area loss down to 87 m2 g-1, well below the values obtained from the nanocrystal building blocks.