Heterogeneous Nucleation Research Articles

Enhanced 3D printing and crack control in melt-grown eutectic ceramic composites with high-entropy alloy doping

As a 3D printing method, laser powder bed fusion (LPBF) technology has been extensively proven to offer significant advantages in fabricating complex structured specimens, achieving ultra-fine microstructures, and enhancing performances. In the domain of manufacturing melt-grown oxide ceramics, it encounters substantial challenges in suppressing crack defects during the rapid solidification process. The strategic integration of high entropy alloys (HEA), leveraging the significant ductility and toughness into ceramic powders represents a major innovation in overcoming the obstacles. The ingenious doping of HEA particles preserves the eutectic microstructures of the Al2O3/GdAlO3(GAP)/ZrO2 ceramic composite. The high damage tolerance of the HEA alloy under high strain rates enables the absorption of crack energy and alleviation of internal stresses during LPBF, effectively reducing crack initiation and growth. Due to increased curvature forces and intense Marangoni convection at the top of the molt pool, particle collision intensifies, leading to the tendency of HEA particles to agglomerate at the upper part of the molt pool. However, this phenomenon can be effectively alleviated in the remelting process of subsequent layer deposition. Furthermore, a portion of the HEA particles partially dissolves and sinks into the molten pool, acting as heterogeneous nucleation particles, inducing the formation of equiaxed eutectic and leading primary phase nucleation. Some HEA particles diffuse into the lamellar ternary eutectic structures, further promoting the refinement of eutectic microstructures due to increased undercooling. The innovative doping of HEA particles has effectively facilitated the fabrication of turbine-structured, conical, and cylindrical ternary eutectic ceramic composite specimens with diameters of about 70 mm, demonstrating significant developmental potential in the field of ceramic composite manufacturing.

Laser powder bed fusion of a Co–Al–W-based composite: Effects of Y2O3 nanoparticles on crack elimination, microstructure and mechanical properties

In order to meet the aerospace industry's growing demand for higher-temperature and more-efficient materials, Co–Al–W-based superalloy was invented in 2006 and is expected to become the next generation of potential superalloys for aero engines. Laser powder bed fusion, as a type of additive manufacturing technology, is considered to be an advanced method for manufacturing aerospace components. However, for Co–Al–W-based superalloy, cracking commonly occurs during this process. To solve the cracking in the non-weldable Co–Al–W-based superalloy during laser powder bed fusion, 0.5 wt% Y2O3 nanoparticles were added to this alloy, forming a Co–Al–W-based composite. The results show that the cracks that formed in the Co–Al–W-based superalloy were attributed to the solidification cracking owing to the formation of the Laves phase in the inter-dendritic region. The added Y2O3 nanoparticles presented a stable chemical state without extra reactions with other elements during the laser powder bed fusion process. They played a heterogeneous nucleation role to induce columnar to equiaxed transition, where the microstructure was refined, and the cracks were eliminated. As a result, the tensile performance was dramatically improved.

Self-assembled complexing agent assisted chemical bath deposition of SnOX enabled highly efficient perovskite solar cells

Chemical bath deposition (CBD) is generally used to fabricate SnOX electron transport layer (ETL) for perovskite solar cells, whereas a lack of understanding of the reaction mechanism hampers further improvement of device performance. Here, we elucidate the reaction mechanism by monitoring the SnOX growth process via a series of advanced X-ray photoelectron spectroscopy studies. For the first time, we successfully modulated the nucleation and crystal growth of SnOX during the CBD process by introducing complexing agent via inherently forming a self-assembled monolayer on the outmost surface of SnOX. The complexing agents can assist the heterogeneous nucleation and crystal growth of SnOX. By a comparison study of different complexing agents, we found that the 2,3-dimercapto-1-propanesulfonate sodium not only assists in achieving a high-quality SnOX ETL, but also serves as a bridge to connect with perovskite via coordination interactions. Leveraging these insights, we achieved a champion efficiency of 24.2 % for perovskite solar cells with ∼ 2300 h stability at ambient condition.

Microstructure and mechanical properties of wire-arc directed energy deposited Al-Mg-Sc aluminum alloy: As-deposited and aging heat treated

In this study, Al-Mg-Sc aluminum alloys were fabricated using wire-arc directed energy deposition. The focus of the study was to analyze the microstructure and mechanical properties of these alloys. Comparative analysis was conducted on the samples obtained from the as-deposited and aging treated, respectively. Furthermore, the precipitation process of the second phases and the associated strengthening mechanism were elucidated. The findings revealed that the presence of precipitated Al3(Sc,Zr) particles acted as heterogeneous nucleation nuclei of α-Al, facilitating the formation of equiaxial grains. During the subsequent aging treatment, the secondary Al3(Sc,Zr) particles precipitated directly without transitioning through intermediate phases. Additionally, the experimental results demonstrated that these secondary Al3(Sc,Zr) phases hindered the dislocation movement, leading to enhanced mechanical properties in Al-Mg-Sc alloys through precipitation strengthening. In the horizontal direction, the average ultimate tensile strength (UTS) and yield strength (YS) were measured as 361 ± 5 MPa, 251 ± 4 MPa, and 281 ± 6 MPa, 179 ± 6 MPa in the vertical direction, respectively. The elongations were found to be 15.8 ± 0.8% and 4.0 ± 0.5% in the horizontal and vertical directions, respectively. The observed variations in mechanical properties were attributed to the presence of interlayer pores.

Preparation of UiO-66 membrane through heterogeneous nucleation assisted growth strategy for efficient CO2 capture under humid conditions

Metal-organic frameworks (MOFs) have driven the development of polycrystalline membranes in the field of gas separation owing to the strong adsorption-desorption behavior and stable framework structure. However, the poor heterogeneous bonding ability between crystals and the substrate leads to the unsatisfactory gas separation as well as low stability of MOF membranes, especially in the humid environment. Herein, we prepared a thin and defect-free UiO-66 membrane by a crystal heterogeneous nucleation assisted growth strategy for efficient CO2/N2 separation. The addition of small amount of water in the precursor solution promoted the crystal nucleation process on the substrate surface. Meanwhile, the smooth PDMS interlayer guaranteed the heterogeneous well-intergrown of crystals into thin UiO-66 membranes, and provided a hydrophobic environment. Therefore, the dense UiO-66 membrane with a small thickness exhibited a high CO2 permeance (177.4 × 10−9 mol·m−2·s−1·Pa−1) with moderate CO2/N2 selectivity (24.3) under humid conditions. Furthermore, the prepared membrane demonstrated excellent renewable performance after dehumidification at high temperature, and maintained good hydrothermal stability during long-term operation under the humid environment. This work provides a new insight for the design of high-quality MOF membranes and promotes the development of MOF membranes in practical gas separation process.

Enhancing reversible hydrogen storage performance of 2LiBH4–MgH2 via in-situ building heterogeneous nucleation sites

Enhancing reversible hydrogen storage performance of 2LiBH4–MgH2 via in-situ building heterogeneous nucleation sites

In-situ observation of DL-alanine crystallization from a laser-trapped dense liquid droplet as a heterogeneous nucleation site

Abstract Nucleation from an aqueous solution is an important step in crystallization which controls the physicochemical properties of crystalline materials. Although dense liquid droplets are considered as a precursor of a crystal in the two-step nucleation model, their actual role is unclear. Our in-situ microscopic observations of the crystallization of DL-alanine from a dense liquid droplet trapped by laser tweezers show that liquid droplets play the role of a substrate, facilitating heterogeneous nucleation, rather than a precursor of a crystal.

Construction of Cs2AgBiCl6/COF Heterojunction for Boosted Photocatalytic Thioester Oxidation.

Lead-free halide perovskites as a new kind of potential candidate for photocatalytic organic synthesis have attracted much attention recently. The rational heterojunction construction is regarded as an efficient strategy to delicately regulate their catalytic performances. Herein, a semi-conductive covalent organic framework (COF) nanosheet, C4N, is employed as the functional component to construct Cs2AgBiCl6/C4N (CABC/C4N) heterojunction. It is found that the C4N nanosheets with rich surface functional groups can serve as heterogeneous nucleation sites to manipulate the growth of CABC nanocrystals and afford close contact between each other, therefore facilitate the transfer and spatial separation of photogenerated charge carriers, as verified by in situ X-ray photoelectronic spectroscopy and Kelvin probe force microscopy. Moreover, the oxygen affinity of C4N endows the heterojunctions with outstanding aerobic reactivity, thus improving the photocatalytic performance largely. The optimal CABC/C4N heterojunction delivers a thioanisole conversion efficiency of 100% after 6h, which is 2.2 and 7.7-fold of that of CABC and C4N. This work provides a new ideal for the design and application of lead-free perovskite heterojunction photocatalysts for organic reactions.

Nanofluidic Platform for Studying the First-Order Phase Transitions in Superfluid Helium-3

The symmetry-breaking first-order phase transition between superfluid phases 3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}He-A and 3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}He-B can be triggered extrinsically by ionising radiation or heterogeneous nucleation arising from the details of the sample cell construction. However, the role of potential homogeneous intrinsic nucleation mechanisms remains elusive. Discovering and resolving the intrinsic processes may have cosmological consequences, since an analogous first-order phase transition, and the production of gravitational waves, has been predicted for the very early stages of the expanding Universe in many extensions of the Standard Model of particle physics. Here we introduce a new approach for probing the phase transition in superfluid 3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}He. The setup consists of a novel stepped-height nanofluidic sample container with close to atomically smooth walls. The 3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}He is confined in five tiny nanofabricated volumes and assayed non-invasively by NMR. Tuning of the state of 3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}He by confinement is used to isolate each of these five volumes so that the phase transitions in them can occur independently and free from any obvious sources of heterogeneous nucleation. The small volumes also ensure that the transitions triggered by ionising radiation are strongly suppressed. Here we present the preliminary measurements using this setup, showing both strong supercooling of 3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}He-A and superheating of 3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}He-B, with stochastic processes dominating the phase transitions between the two. The objective is to study the nucleation as a function of temperature and pressure over the full phase diagram, to both better test the proposed extrinsic mechanisms and seek potential parallel intrinsic mechanisms.

A new heterogeneous nucleation mechanism of AM30 alloy refined by carbon inoculation

The AM30 alloy experiences remarkable grain refinement through carbon inoculation, resulting in a significant reduction of grain size from 623±21μm to 82 ± 2 μm. To delve into the influence of Mn on carbon inoculation in the presence of Ca, advanced techniques such as EDS, FIB, and TEM were utilized. This study reports the initial discovery of a unique duplex-phase particle characterized by an amorphous carbon layer coating on the Al8Mn5 phase. Notably, the amorphous layer exhibits a thickness of approximately 100 nm. These distinctive duplex-phase particles are hypothesized to serve as effective nuclei for Mg grains. Supported by epitaxial growth theory and experimental data, these particles exhibit remarkable nucleation efficiency.

A unique microstructure and its formation mechanism induced by laser cladding of Ti6Al4V alloy produced by laser powder bed fusion

A nickel based gradient laser cladding layer was successfully prepared on Ti6Al4V alloy produced by laser powder bed fusion (L-PBF). The nickel-enriched area of middle layer (NEAm) in the cladding layer had a unique structure. NEAm was composed of many large strip-like Ti2Ni grains. The sub-grain inside a single Ti2Ni grain presented a fine dendrite structure (these small dendrite units belong to the same grain, which was different from the traditional dendrite structure, so it was called "pseudo-dendrite"), the interdendrite was composed of amorphous phase or alternating β-Ti, Ti5Si3 nano-grains or mixtures of amorphous phase and the alternating structure. There were many massive TiNi and dispersed Y2O3, TiC and other fine second phase particles in the dendrite stem. Some of the Si-rich amorphous phase in the interdendrite transformed into alternating β-Ti and Ti5Si3 nano-grains. Thermodynamic calculation showed that the Gibbs free energies of amorphous phase in the top layer and NEAm were −13.353 and −33.619 kJ/mol, respectively. The glass-forming ability (GFA) values γABC* of the top layer and NEAm were 1.813 and 3.067, respectively. Obviously, the amorphous phase formation was easier in the NEAm than in the top layer, which explains the reason that although the cooling rate in the NEAm is slower than that in the top layer, the amorphous phase is only generated in the NEAm. The two-dimensional mismatch between of Y2O3 and Ti2Ni reached 15.43%, which was larger than the limit value of heterogeneous nucleation (12%), so Y2O3 in the NEAm did not play a role in heterogeneous nucleation. An unreported metastable phase was identified in a grain of Y2O3 in the NEAm. Since this phase was sensitive to electron irradiation, extremely limited photo-information was acquired. Accordingly, the Bravais lattice of the metastable phase was reconstructed; its most likely structure was simple cubic. Its lattice constant was anew phase = 3aorigin Y2O3 = 1.8369 nm, α = β = γ = 90°. Its orientational relationship with the parent-phase Y2O3 was ｛12̅1｝origin Y2O3∥｛110｝new phase，<1̅01>origin Y2O3∥<1̅10>new phase. The large increase of the phase interface, the pinning effect of the second phase, and the formation of amorphous phase significantly increased the hardness(up to 1100HV).

Enhanced pitting resistance for high-entropy alloys by precipitating nano-sized L12-strengthened phase

Precipitation-strengthened HEAs exhibit outstanding integration of strength and toughness at ambient temperature. Nevertheless, precipitates generally reduce the localized corrosion resistance in aggressive solution environments. To solve this problem, a strategy of introducing nano-sized L12 precipitates in CoCrFeNiAlTi HEAs has been proposed in this work. Results demonstrate the pitting corrosion potential can be elevated from 258 mVSCE to 603 mVSCE by increasing the precipitate content to 38 wt.%. Such an improvement in localized corrosion resistance can be attributed to two aspects. Firstly, L12 precipitates tend to be dissolved during the corrosion process, which promotes the heterogeneous nucleation of protective Cr2O3 due to the rapid deposition of oxides/hydroxides of Al/Ti, and improves the passive film stability due to the Cr-rich FCC matrix. Secondly, the dissolution kinetic inside the pits can be suppressed on account of the enrichment of Cr element in the FCC matrix, thus inhibiting the pitting growth. In summary, the current work not only reveals the mechanisms of the nano-sized L12 precipitates upon the corrosion behavior, but also provides a strategy for designing corrosion-resistant HEA.

The impact of aerosols as ice nucleating particle on microphysics and electrification in the cumulus model

Here, a heterogeneous ice nucleation parameterization associated with aerosol acting as ice nucleating particle (INP) was implanted into a two-dimensional numerical cumulus model. To explore the impact of INP on microphysical and electrical processes, a comparison was conducted with the original approach, which employs an empirical formula. Simulation results indicate that INP greatly impacted microphysical evolution in the heterogeneous ice nucleation process, reducing total liquid precipitation amounts and causing a slight precipitation delay, as well as increasing the diameter and mixing ratio of ice crystals and the expansion of the vertical distribution of ice crystals. This led to a notable change in electrification in thunderstorms. The increase of ice crystal diameter was the dominant contributor to the enhancement of electrification using the new parameterization. Additionally, unlike the structure of thunderclouds in a mature stage, which always retains a normal dipole structure adopting the empirical formula, a tripole structure developed a lower positive charge, and the polarity inversion with upper negative and lower positive charges occurred when the new parameterization was adopted. This predominately was the result of abundant ice crystals present below the reversal temperature. The electrification characteristics of thunderstorms may have a close connection with lightning activity. It has been found that charge structure changed significantly in the two cases, with the tripolar charge structure facilitating the production of inverted intra-cloud (IC) flashes and negative Cloud-to-ground (CG) flashes simulated by the new parameterization; additionally, clouds simulated using the empirical formula may be able to develop normal IC lightning and positive CG flashes. Therefore, it will be very meaningful to obtain greater insight into the characteristics of thunderstorms electrification in cumulus model with aerosols.

Experimental characterization and 3D sharp-interface model simulation of grain refinement during solidification of nano-TiCN/Al–7Si composites

Significant grain refinement was achieved in nano-TiCN/Al-7 wt.% Si composites through growth control induced by nano-TiCN particles (NPs). The microstructures displayed two types of NP distributions: within interdendritic eutectic Si phase and along grain boundaries. This refined microstructure contributed to enhancing mechanical properties. To elucidate the grain refinement mechanism in nano-TiCN/Al–7Si composites, a three-dimensional (3D) sharp interface model (SIM) was developed, integrating the cellular automaton (CA) technique with a transformation matrix comprising three Euler angles. This 3D SIM effectively replicated the dendritic morphology of α-Al. The exact impact of latent heat on grain refinement was clarified. The observed grain refinement induced by NPs could not be numerically reproduced without considering latent heat. The grain refinement in TiCN/Al–7Si composites is governed by multiple factors. As NPs layers inhibits solute diffusion along the solid-liquid interface, the dendrite growth rate reduces, leading to the reduced rate of latent-heat release. Consequently, constitutional undercooling in the surrounding liquid increases, activating more heterogeneous nuclei. The developed SIM model offers deeper insights into the grain refinement mechanism induced by TiCN NPs in Al–7Si alloy.

Microstructure and mechanical properties of 7075/5356 aluminum alloy laminated composite fabricated by wire arc additive manufacturing

A 7075/5356 aluminum alloy laminated composite was fabricated by alternately depositing a 7075 wire and a 5356 wire layer by layer using wire arc additive manufacturing (WAAM). The microstructure and mechanical properties of the produced components under as-deposited and heat-treated conditions were investigated. The results revealed that the grain morphology of the specimen was mainly composed of equiaxed grains in each layer, while the grain size of the interlayer region was reduced due to the heterogeneous nucleation relying on the partially remelted previous layer. Moreover, a reduced amount of second phase was observed due to decreased Zn and Cu alloying elements content in this region, which resulted in a gradient change in microhardness distribution. The tensile strength and elongation of the heat-treated samples in vertical and horizontal directions were 321 MPa, 10.12 %, and 377 MPa, 9.72 %, respectively. The results indicated good comprehensive mechanical properties, which is promising for further application of WAAM fabricated laminated metal composite.

Origin and Nucleation Kinetics of Transcrystalline Layer in Bamboo fiber@nano‐TiO2/Polypropylene Composite

AbstractHerein origin and nucleation kinetics of transcrystalline layer (TCL) in bamboo fiber deposited with nano‐TiO2 (BF@TiO2)/polypropylene (PP) composite is studied. Firstly, the surface morphology, roughness, and energy, as well as crystalline structure (e. g., crystal face indices (hkl)) of BF@TiO2 are analyzed to clarify the origin of TCL in the composite. Subsequently, the nucleation kinetics of TCL in BF@TiO2/PP composite at different crystallization temperatures (Tc) are investigated through polarized optical microscopy. The results find that the surface roughness and energy of BF@TiO2 increase by 47.55 % and 2.41 % compared with untreated BF, respectively. Interestingly, the mismatch rates (MRs) of hkl(BF) vs. hkl(PP) are &gt;320 %. In comparison, the MRs of (101)(BF@TiO2)TiO2 vs. (hkl)(PP) are dramatically decreased to &lt;25 %, suggesting a similar crystal plane between BF@TiO2 and PP matrix. These results indicate that the TCL formation in the composite is more facile in BF@TiO2 than in the untreated BF. During isothermal crystallization, the nucleation and spherulite growth rates decrease as the Tc increases. The interface free energy difference (▵σ) between BF@TiO2 and PP is calculated based on the heterogeneous nucleation theory. The ▵σ is 1.54±0.11 J cm−2, highlighting that the BF@TiO2 strongly induces the PP nucleation.

Enhanced heterogeneous nucleation in Al alloys by melt ultrasonic treatment

The mechanisms of grain refinement in the A1050 alloy through melt ultrasonic treatment (UT) and isothermal holding were investigated. The results showed that UT resulted in considerable grain refinement, with refining efficiency tending to stabilize after 15 min of holdings. Meanwhile, it was found that UT breaks down natural oxide films into fine γ-Al2O3 particles with {111} or {110} exposed surfaces. The well-defined cube-on-cube orientation relationships between γ-Al2O3 and α-Al verify that γ-Al2O3 dispersoids can act as potent substrates for the nucleation of α-Al grains. Based on experimental observations and theoretic calculations, enhanced heterogeneous nucleation in A1050 alloys can be attributed to the high potency of γ-Al2O3 particles with atomic misfits of ∼2 % on all exposed surfaces and their increased number density induced by the synergistic effects of cavitation and acoustic streaming.

Disparity-driven heterogeneous nucleation in finite-size adaptive networks.

Phase transitions are crucial in shaping the collective dynamics of a broad spectrum of natural systems across disciplines. Here, we report two distinct heterogeneous nucleation facilitating single step and multistep phase transitions to global synchronization in a finite-size adaptive network due to the trade off between time scale adaptation and coupling strength disparities. Specifically, small intracluster nucleations coalesce either at the population interface or within the populations resulting in the two distinct phase transitions depending on the degree of the disparities. We find that the coupling strength disparity largely controls the nature of phase transition in the phase diagram irrespective of the adaptation disparity. We provide a mesoscopic description for the cluster dynamics using the collective coordinates approach that brilliantly captures the multicluster dynamics among the populations leading to distinct phase transitions. Further, we also deduce the upper bound for the coupling strength for the existence of two intraclusters explicitly in terms of adaptation and coupling strength disparities. These insights may have implications across domains ranging from neurological disorders to segregation dynamics in social networks.

Controlling the crystal morphology of high-hardness TPU through two pre-crystallization processes and its impact on physical foaming behavior

Clarifying the relationship between crystal evolution and the physical foaming behavior of high-hardness thermoplastic polyurethane (HD-TPU) is essential for preparing HD-TPU foams with controllable cellular morphology. In this study, two thermal treatment methods, isothermal annealing and isothermal crystallization, were utilized to control the crystal structure of HD-TPU. The effect of crystals on the physical foaming behavior of HD-TPU foams was examined. The annealing process produced mainly lamellae and Form Ⅰ structure, while isothermal crystallization primarily led to Form Ⅱ spherulites. Foams based on original and pre-treated HD-TPU were prepared by pressure quench foaming. The evolution of foam density and cell morphology was discussed. At low foaming temperatures, crystals induced the heterogeneous nucleation. Realizing a uniform cell structure at high foaming temperatures could be challenging when the spherulite size was large. When the size of the spherulite was small but loosely distributed, larger cells with thinner cell walls could be obtained. However, if the spherulite distribution was dense, the spherulites hindered cell growth, resulting in unevenly distributed and deformed cells.

Hydrogel Nanoparticles Enable Nucleation Barrier Regulation and Ion Anchoring as an Alternative Pathway for Monosodium Urate Monohydrate Crystallization Control.

Gout flare-up, commonly resulting from monosodium urate monohydrate (MSUM) crystallization, has led to painful inflammatory arthritis among hundreds of millions of people. Herein, a kind of hydrogel nanoparticles (HNPs) with specific properties was developed, aimed at providing a promising pathway for MSUM crystallization control. The experimental and molecular dynamics simulation results synchronously indicate that the fabricated HNPs achieve efficient inhibition of MSUM crystallization governed by the mechanism of "host-guest interaction" even under very low-dose administration. HNPs as the host dispersed in the hyperuricemic model effectively lift the relative heterogeneous nucleation barrier of the MSUM crystal and hinder solute aggregation with strong electronegativity and hydrophobicity. The initial appearance of MSUM crystals was then delayed from 94 to 334 h. HNPs as the guest on the surface of the formed crystal can decelerate the growth rate by anchoring ions and occupying the active sites on the surface, and the terminal yield of the MSUM crystal declined to less than 1% of the control group. The good biocompatibility of HNPs (cell viability > 94%) renders it possible for future clinical applications. This study can guide the rational design of inhibitory nanomaterials and the development of their application in the control of relevant pathological crystallization.