Spherical Iron Oxide Research Articles

Synthesis, characterization, and ameliorative effect of iron oxide nanoparticles on saline-stressed Zea mays

High soil salinity induces osmotic and ionic stress that threaten crop production worldwide and affect food security. This study evaluated the ameliorative effects of iron oxide nanoparticles on salinized Zea mays. Iron oxide nanoparticles were synthesized using an aqueous leaf extract of Diodella sarmentosa, and the results of the characterization using Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDX), transmission electron microscope (TEM), UV–visible spectrophotometer, and scanning electron microscope (SEM) revealed the presence of polydisperse spherical iron oxide nanoparticles (FeONPs) with a light absorption peak at 290 nm, and a size ranging from 3.03 nm to 87.04 nm. Daily foliar application of FeONPs on the salinized Zea mays for 10 days, significantly (p < 0.05) improved the plant’s photosynthetic pigments (total chlorophyl (175.71 %), chlorophyll a (256.34 %), chlorophyll b (77.01 %), carotenoid (39.36 %), root length (9.87 %), and antioxidant enzyme activities, compared to the untreated and bulk FeCl3·6H2O-treated controls. Since iron is known to promote photosynthetic pigment synthesis, the enhanced photosynthetic indices observed in the FeONPs-treated pot compared to the bulk FeCl3·6H2O-treated pot, may have resulted from the size-aided absorption of the FeONPs more than FeCl3·6H2O From the findings, it can be deduced that FeONPs can improve the growth and development of saline-stressed Zea mays by enhancing the activities of the antioxidant enzymes, while improving the photosynthetic pigments of the plant.

Defects or no defects? Or how to design 20-25 nm spherical iron oxide nanoparticles to harness both magnetic hyperthermia and photothermia.

Designing iron oxide nanoparticles (IONPs) to effectively combine magnetic hyperthermia (MH) and photothermia (PTT) in one IONP formulation presents a significant challenge to ensure a multimodal therapy allowing the adaptation of the treatment to each patient. Recent research has highlighted the influence of factors such as the size, shape, and amount of defects on both therapeutic approaches. In this study, 20-25 nm spherical IONPs with a spinel composition were synthesized by adapting the protocol of the thermal decomposition method to control the amount of defects. By tuning different synthesis parameters such as the precursor nature, the introduction of a well-known oxidizing agent, dibenzylether (DBE), in the reaction medium, the heating rate and duration and the introduction of a nucleation step, we thus established two different synthesis protocols, one involving the use of a small amount of DBE leading to IONPs with only a few defects and another that took an optimized route to oxidize the wüstite nuclei during the IONP growth and led to IONPs exhibiting more structural and oxygen defects. IONPs exhibiting fewer defects showed enhanced MH and PTT heating values even when immobilized in a matrix, despite a decrease in MH heating values showing that they release mainly heat through the Brownian mechanism. These MH measurements have also confirmed that defects play a key role in enhancing Néel relaxation. PTT measurements demonstrated higher heating values with IONPs with fewer defects and a correlation between Urbach energy and SAR values suggesting an impact of vacancy defects on PTT performances. Therefore, IONPs exhibiting fewer defects under our synthesis conditions appear as suitable IONPs to combine both MH and PTT treatments with high performances. These findings pave the way for promising applications in combined therapies for cancer treatment.

DIFFUSION INTERACTION MODEL IN AL-FE2O3 SYSTEM INCLUDING THE FORMATION OF INTERMETALLIC PHASES

In this paper, we consider the problem of interaction of a spherical iron oxide particle with an aluminum melt surrounding it. A comparison of two different approaches to describing the interaction in the Al-Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; system suitable for various temperature intervals is presented. The first of these is the problem with the volume reaction. This problem is solved numerically by front straightening method. The counter-sweep method and an implicit difference scheme are used. The second variant of the model corresponds to sequential reactions and is typical for reactive diffusion theory. This is applicable to another temperature interval when intermetallide does not transfer to the melt. This problem is solved in the quasi-stationary approximation. The results show that both models give similar dynamics of the appearance of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; oxide. Different rates of intermetallide accumulation reflect different reaction mechanisms in different temperature intervals. Both approaches can be applied to describe the process of phase formation in other, more complex systems.

Magnetic Susceptibility and Hydrogen Cyanide Levels as Proxy Indicator for Gold Mining Pollution in River Sediment

Sumbawa’s Kuris River is one of the rivers contaminated by the island’s traditional gold mine. In order to detect contaminant levels, we examine the magnetic susceptibility, HCN levels, and the heavy metal contents on the river’s surface sediment. Environmental pollution has been widely assessed using a combination of magnetic properties and geochemical analysis. The goals of this research are to discover how magnetic susceptibility (χ) can be used as a first-order proxy for pollution. The relation between susceptibility and HCN is of particular interest, as this is a major contaminant associated with gold mining. The surface sediment samples were collected at ten different locations along the rivers. The magnetic susceptibility was determined using the Bartington MS2B, and the hydrogen cyanide (HCN) concentration was determined using Argentometric titration. The element content was determined by an Atomic Absorption Spectrometer (AAS). The low-frequency magnetic susceptibility (χlf) ranges from 71 to 115×10-8 m3/kg, with an average of 97×10-8 m3/kg, and the χfd(%) analysis ranges from 2% to 4%. The presence of spherical iron oxides, which are indicative of combustion byproducts, was also confirmed by SEM. The samples have low magnetic susceptibility but high levels of Hg and HCN. AAS results showed high Fe, Zn, and Cu concentrations in river sediments, with more variable concentrations of Hg, Mn, As, Cr, and Au. Because Fe, Cu, As, Hg, and HCN have a significant Pearson’s correlation with χfd(%), this parameter can be a useful indicator for contamination caused by gold mining waste.

Experimental study of explosion overpressure and flame propagation of micro‐sized and nanosized iron powder

AbstractIn order to study the explosion of micro‐sized and nanosized iron powder, the explosion overpressure and flame propagation were measured in a 20‐L near‐spherical explosion pressure experiment and a Hartmann tube experiment. The explosion overpressure experiments show that the optimum explosion concentrations of micro‐sized and nanosized iron powder are 750 and 375 g/m3, respectively. The maximum explosion pressure and the maximum explosion pressure rise rate of nanosized iron powder are 0.56 MPa and 46.41 MPa/s, which are 144% and 225% of that of micro‐sized iron powder, respectively. Under the optimum explosion concentration, the explosion flame of nanosized iron powder is brighter, and the propagation time is shorter. The maximum propagation velocity of micro‐sized and nanosized iron powder flame is 0.84 and 6.55 m/s, respectively, and the flame pulsation degree of micro‐sized iron powder is larger. The spherical particles and the cracks on the surface of the product particles were observed in the micro images of the explosion products, and the explosion mechanism model of micro‐sized and nanosized iron powder was obtained. It was observed that the deformation of micro‐sized iron particles intensifies, forming regular and complete spherical iron oxide particles.

Tailoring defects and nanocrystal transformation for optimal heating power in bimagnetic CoyFe1-yO@CoxFe3-xO4 particles.

The effects of cobalt incorporation in spherical heterostructured iron oxide nanocrystals (NCs) of sub-critical size have been explored by colloidal chemistry methods. Synchrotron X-ray total scattering methods suggest that cobalt (Co) substitution in rock salt iron oxide NCs tends to remedy their vacant iron sites, offering a higher degree of resistance to oxidative conversion. Self-passivation still creates a spinel-like shell, but with a higher volume fraction of the rock salt Co-containing phase in the core. The higher divalent metal stoichiometry in the rock salt phase, with increasing Co content, results in a population of unoccupied tetrahedral metal sites in the spinel part, likely through oxidative shell creation, involving an ordered defect-clustering mechanism, directly correlated to core stabilization. To shed light on the effects of Co-substitution and atomic-scale defects (vacant sites), Monte Carlo simulations suggest that the designed NCs, with desirable, enhanced magnetic properties (cf. exchange bias and coercivity), are developed with magnetocrystalline anisotropy which increases due to a relatively low content of Co ions in the lattice. The growth of optimally performing candidates combines also a strongly exchange-coupled system, secured through a high volumetric ratio rock salt phase, interfaced by a not so defective spinel shell. In view of these requirements, specific absorption rate (SAR) calculations demonstrate that the rock salt core sufficiently protected from oxidation and the heterostructure preserved over time, play a key role in magnetically mediated heating efficacies, for potential use of such NCs in magnetic hyperthermia applications.

Preparation of doxorubicin-loaded porous iron Oxide@ polydopamine nanocomposites for MR imaging and synergistic photothermal–chemotherapy of cancer

Recently, the development of biosafe nanocomposites with integrated diagnosis and therapeutic modality is received great attention in anti-cancer drug delivery. In this sturdy, we developed a multifunctional PION@PDA-PEG nanocomposite that combines the functions of magnetic resonance (MR) imaging, photothermal therapy (PTT) and chemotherapy into one single nanoprobe. The spherical and uniform-sized porous iron oxide nanoparticles (PION) were synthesized via a simple solvothermal method. Subsequently, a near-infrared light (NIR) sensitive polydopamine (PDA) shell was directly coated on the surface of PIONs to form monodisperse and biosafe core-shell nanocomposites, Thereafter, the surface of nanocomposites was further modified with polyethylene glycol (PEG) to prolong their blood circulation lifetime. The prepared PION@PDA-PEG showed excellent biocompatibility and promising MR imaging contrast agent capability. Furthermore, the porous structure of PION and the abundant functional groups of PDA shell permitted the remarkable drug loading capacity of more than 24.1 wt%. In addition, the synergistic photothermal- chemotherapy exhibited obvious enhanced anti-tumor effect in in-vitro cell experiment. These results suggest that the developed PION@PDA-PEG nanocomposite can be utilized as an efficient drug nanocarrier for biomedical applications including MR imaging and photothermal-chemotherapy.

Personalised Profiling of Innate Immune Memory Induced by Nano-Imaging Particles in Human Monocytes.

Engineered nanoparticles used for medical purposes must meet stringent safety criteria, which include immunosafety, i.e., the inability to activate possibly detrimental immune/inflammatory effects. Even medical nanomaterials devoid of direct immunotoxic or inflammatory effects may have an impact on human health if able to modify innate memory, which is the ability to “prime” future immune responses towards a different, possibly more detrimental reactivity. Although innate memory is usually protective, anomalous innate memory responses may be at the basis of immune pathologies. In this study, we have examined the ability of two nanomaterials commonly used for diagnostic imaging purposes, gold and iron oxide nanoparticles, to induce or modulate innate memory, using an in vitro model based on human primary monocytes. Monocytes were exposed in culture to nanoparticles alone or together with the bacterial agent LPS (priming phase/primary response), then rested for six days (extinction phase), and eventually challenged with LPS (memory/secondary response). The memory response to the LPS challenge was measured as changes in the production of inflammatory (TNFα, IL-6) and anti-inflammatory cytokines (IL-10, IL-1Ra), as compared to unprimed monocytes. The results show that both types of nanoparticles can have an effect in the induction of memory, with changes observed in the cytokine production. By comparing nanomaterials of different shapes (spherical vs. rod-shaped gold particles) and different size (17 vs. 22 nm diameter spherical iron oxide particles), it was evident that innate memory could be differentially induced and modulated depending on size, shape and chemical composition. However, the main finding was that the innate memory effect of the particles was strongly donor-dependent, with monocytes from each donor showing a distinct memory profile upon priming with the same particles, thereby making impossible to draw general conclusions on the particle effects. Thus, in order to predict the effect of imaging nanoparticles on the innate memory of patients, a personalised profiling would be required, able to take in consideration the peculiarities of the individual innate immune reactivity.

Fréedericksz Transitions in 6CB Based Ferronematics-Effect of Magnetic Nanoparticles Size and Concentration.

In this paper, results acquired from capacitance measurements performed on composites based on nematic liquid crystal 4-cyano-4′-hexylbiphenyl (6CB) and spherical iron oxide nanoparticles of various sizes are presented. Electric and magnetic Fréedericksz transitions, as well as structural transitions in combined electric and magnetic fields, were investigated. The obtained results showed the lowering of the threshold magnetic field with an increase in the volume concentration of nanoparticles. Estimations based on results obtained from measurements suggest soft anchoring between liquid crystal director and nanoparticles magnetization vector.

Magnetic Nanoparticles: Unravelling Magnetic Nanochain Formation in Dispersion for In Vivo Applications (Adv. Mater. 24/2021)

Spherical iron oxide nanoparticles in dispersion are controlled by external magnetic fields to form flexible and reversible chains for biomedical applications. In article number 2008683, Mikhail Feygenson and co-workers combine the advanced scattering methods and reverse Monte Carlo simulations to directly visualize the chain formation in real space. This methodology paves the way for exploring novel assemblies of particles with a complex morphology in various liquid carriers.

Magnetic properties and its application in the prediction of potentially toxic elements in aquatic products by machine learning

Magnetic measurement was provided to substitute for time-consuming conventional methods for determination of potentially toxic elements. Both the concentrations of 12 elements and 9 magnetic parameters were determined in 700 muscle tissue samples from the snail Bellamya aeruginosa, shrimp species Exopalaemon modestus and Macrobrachium nipponense, and fish species Hemisalanx prognathous Regan, Coilia ectenes taihuensis, and Culer alburnus Basilewsky collected from Chaohu Lake during different hydrological periods. Spherical and irregular iron oxide particles were observed in the muscle tissues of the studied aquatic products. A field survey of the exposure parameters in humans, such as per capita intake dose of local aquatic products, found no evidence that consumption of the tested species poses a potential health risk. Redundancy analysis revealed different degrees of correlation between the magnetic parameters and concentrations of elements in aquatic products. Back-propagation artificial neural network (BP-ANN) and support vector machine (SVM) models were applied to predict elemental concentrations in aquatic products, using magnetic parameters as input. SVM models performed well in predicting the presence of Cr and Ni, with R and index of agreement values of >0.8 in both training and validation stages as well as relatively low errors. The BP-ANN and SVM models both performed relatively poorly in predicting the presence of Cd and Zn in aquatic products, with R values between 0.333 and 0.718 for Cd and between 0.454 and 0.664 for Zn in training and validation stages. For most of the elements, a better R value was obtained with the SVM than with BP-ANN model. The R of Co, Cr, Cu, Ni, and Ti in the training and validation stages of snail in the SVM model were >0.8. This study is a first step in developing a novel approach allowing the rapid monitoring of potentially toxic elements concentrations in aquatic products.

Role of Magnetic Anisotropy on the Hyperthermia Efficiency in Spherical Fe3−xCoxO4 (x = 0–1) Nanoparticles

The use of magnetic nanoparticles in the treatment of cancer using alternating current hyperthermia therapy has shown the potential to replace or supplement conventional cancer treatments, radiotherapy and chemotherapy, which have severe side effects. Though the nearly spherical sub-10 nm iron oxide nanoparticles have their approval from the US Food and Drug Administration, their low heating efficiency and removal from the body after hyperthermia treatment raises serious concerns. The majority of magnetic hyperthermia research is working to create nanomaterials with improved heating efficiency and long blood circulation time. Here, we have demonstrated a simple strategy to enhance the heating efficiency of sub-10 nm Fe3O4 nanoparticles through the replacement of Fe+2 ions with Co+2 ions. Magnetic and hyperthermia experiments on the 7 nm Fe3−xCoxO4 (x = 0–1) nanoparticles showed that the blocking temperature, the coercivity at 10 K, and the specific absorption rate followed a similar trend with a maximum at x = 0.75, which is in corroboration with the theoretical prediction. Our study revealed that the heating efficiency of the Fe3−xCoxO4 (x = 0–1) nanoparticles varies not just with the size and saturation magnetization but also with the magnetocrystalline anisotropy of the particles.

Mechanical Reshaping of Inorganic Nanostructures with Weak Nanoscale Forces.

Inorganic nanomaterials are often depicted as rigid structures whose shape is permanent. However, forces that are ordinarily considered weak can exert sufficient stress at the nanoscale to drive mechanical deformation. Here, we leverage van der Waals (VdW) interactions to mechanically reshape inorganic nanostructures from planar to curvilinear. Modified plate deformation theory shows that high-aspect-ratio two-dimensional particles can be plastically deformed via VdW forces. Informed by this finding, silver nanoplates were deformed over spherical iron oxide template particles, resulting in distinctive bend contour patterns in bright-field (BF) transmission electron microscopy (TEM) images. High-resolution TEM images of deformed areas reveal the presence of highly strained bonds in the material. Finally, we show that the distance between two nearby template particles allows for the engineering of several distinct curvilinear morphologies. This work challenges the traditional view of nanoparticles as static objects and introduces methods for postsynthetic mechanical shape control.

A Gas Sensor With Fe2O3 Nanospheres Based on Trimethylamine Detection for the Rapid Assessment of Spoilage Degree in Fish.

A spherical iron oxide precursor was prepared using a solvothermal method, and then treated thermally at 400°C to obtain α-Fe2O3 nanoparticles. The structures and morphology of the as-obtained products were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results showed that the diameter of the α-Fe2O3 nanoparticles was approximately 500 nm. In addition, we formed the α-Fe2O3 nanoparticles into a thick film as a gas sensor and performed a gas sensing test. When the working temperature was set at 250°C, the α-Fe2O3 nanoparticle displayed very good selectivity and high sensitivity for trimethylamine (TMA). The minimum detection was as low as 1 ppm, and the response value for 100 ppm TMA gas was 27.8. Taken together, our findings illustrated that the α-Fe2O3 nanoparticles could be used as a gas-sensitive material to test the freshness of fish.

Strong Macroscale Supercrystalline Structures by 3D Printing Combined with Self‐Assembly of Ceramic Functionalized Nanoparticles

To translate the exceptional properties of colloidal nanoparticles (NPs) to macroscale geometries, assembly techniques must bridge a 106‐fold range of length. Moreover, for successfully attaining a final mechanically robust nanocomposite macroscale material, some of the intrinsic NPs’ properties have to be maintained while minimizing the density of strength‐limiting defects. However, the assembly of nanoscale building blocks into macroscopic dimensions, and their effective macroscale properties, are inherently affected by the precision of the conditions required for assembly and emergent flaws including point defects, dislocations, grain boundaries, and cracks. Herein, a direct‐write self‐assembly technique is used to construct free‐standing, millimeter‐scale columns comprising spherical iron oxide NPs (15 nm diameter) surface functionalized with oleic acid (OA), which self‐assemble into face‐centered cubic (FCC) supercrystals in minutes during the direct‐writing process. The subsequent crosslinking of OA molecules results in nanocomposites with a maximum strength of 110 MPa and elastic modulus up to 58 GPa. These mechanical properties are interpreted according to the flaw size distribution and are as high as newly engineered platelet‐based nanocomposites. The findings indicate a broad potential to create mechanically robust, multifunctional 3D structures by combining additive manufacturing with colloidal assembly.

Eco-benign approach to synthesize spherical iron oxide nanoparticles: A new insight in photocatalytic and biomedical applications

Iron oxide nanoparticles (Fe2O3NPs) are an interested and attractive area of research as they have numerous effective environmental and biomedical applications. Herein we have reported a simple and eco-benign synthesis Fe2O3NPs using Tamarix aphylla extract. The extract of the Tamarix aphylla acts both as a reducing and capping agent which leads to the fast and successful eco-benign synthesis of Fe2O3NPs.UV/Vis spectroscopy, XRD, EDX, SEM and TEM techniques were used to characterize and explore different features of Fe2O3NPs. UV/Vis studies showed asharppeak at 390 nm due to surface plasmon resonance absorption of Fe2O3NPs. XRD studies indicated that Fe2O3NPs were crystalline in nature. Structural features, elemental composition and geometry of Fe2O3NPswere confirmed by SEM, EDX and TEM. The as synthesized Fe2O3NPs showed efficient efficacy to degrade 100% of Methylene blue (MB) dye by 4 mg/25 ml MB and revealed 90% scavenging of the more stable DPPH free radical(1 mg/ml). Furthermore, Fe2O3NPs showed excellent antimicrobial activity against pathogenic multidrug resistant bacterial strains. The results of the present study explored the potential reducing, capping property of Tamarix aphylla extract, photocatalytic and biomedical applications of eco-benignly synthesized Fe2O3NPs which could be an alternative material for effective remediation of lethal organic pollutants and microbes.

Star-Shaped Fe3-xO4-Au Core-Shell Nanoparticles: From Synthesis to SERS Application.

In this work, the preparation of magneto-plasmonic granular nanostructures and their evaluation as efficient substrates for magnetically assisted surface enhanced Raman spectroscopy (SERS) sensing are discussed. These nanostructures consist of star-shaped gold Au shell grown on iron oxide Fe3-xO4 multicores. They were prepared by seed-mediated growth of anisotropic, in shape gold nanosatellites attached to the surface of polyol-made iron oxide polycrystals. In practice, the 180 nm-sized spherical iron oxide particles were functionalized by (3-aminopropyl) triethoxysilane (APTES) to become positively charged and to interact, in solution, with negatively charged 2 nm-sized Au single crystals, leading to nanohybrids. These hybrids acted subsequently as nucleation platforms for the growth of a branched gold shell, when they were contacted to a fresh HAuCl4 gold salt aqueous solution, in the presence of hydroquinone, a reducing agent, for an optimized nominal weight ratio between both the starting hybrids and the gold salt. As expected, the resulting nanocomposites exhibit a high saturation magnetization at room temperature and a rough enough plasmonic surface, making them easily attracted by a lab. magnet, while exhibiting a great number of SERS hot spots. Preliminary SERS detection assays were successfully performed on diluted aqueous thiram solution (10−8 M), using these engineered substrates, highlighting their capability to be used as chemical trace sensors.

Efficient oxidation and adsorption of As(III) and As(V) in water using a Fenton-like reagent, (ferrihydrite)-loaded biochar.

The by-product of the traditional Fenton reaction, colloidal arsenic-‑iron oxide, is migratable and may cause secondary environmental pollution. This paper reported a new strategy involving oxidizing and immobilizing inorganic arsenic using the Fenton reaction, and avoiding the risk of secondary contamination. Lab synthesized ferrihydrite-loaded biochar (FhBC) was developed for oxidizing and binding As(III) and As(V) in aqueous solution. Batch experiments and a series of spectrum analysis (e.g., X-ray photoelectron spectroscopy [XPS], electron paramagnetic resonance [EPR], and Fourier transform infrared spectroscopy [FTIR]) were conducted to study the oxidizing or adsorption capacity and mechanism. The maximum adsorption capacity of FhBC for As(III) and As(V) is 1.315 and 1.325mmol/g, respectively. In addition, FhBC has an efficient oxidizing capacity within a wide pH range, which is because biochar promotes the Fenton reaction by acting as an electron donator, electron shuttler, or by providing persistent free radicals. Moreover, the adsorption mechanism was studied by FTIR spectroscopy, XPS, and X-ray diffraction (XRD). The formation of internal spherical complexes and iron oxides with a higher degree of crystallization was observed, which indicate that the products of adsorption are stable and robust in a complex environment and can exist in a highly crystallized form after adsorbing arsenic ions. Therefore, the use of FhBC as an adsorbent for arsenic represents a new strategy of using the Fenton reaction while reducing secondary contamination. These results may contribute to further mechanistic studies or extensive practical applications of FhBC.

Spherical iron oxide methyltrimethoxysilane nanocomposite for the efficient removal of lead(II) ions from wastewater: kinetic and equilibrium studies

Spherical iron oxide methyltrimethoxysilane nanocomposite for the efficient removal of lead(II) ions from wastewater: kinetic and equilibrium studies

Structural Properties and Magnetic Ordering in 2D Polymer Nanocomposites: Existence of Long Magnetic Dipolar Chains in Zero Field.

The existence of magnetic dipolar nanoparticle chains at zero field has been predicted theoretically for decades, but these structures are rarely observed experimentally. A prerequisite is a permanent magnetic moment on the particles forming the chain. Here we report on the observation of magnetic dipolar chains of spherical iron oxide nanoparticles with a diameter of 12.8 nm. The nanoparticles are embedded in an ultrathin polymer film. Due to the high viscosity of the polymer matrix, the dominating aggregation mechanism is driven by dipolar interactions. Smaller iron oxide nanoparticles (8 nm) show no permanent magnetic moment and do not form chains but compact aggregates. Mixed monolayers of iron oxide nanoparticles and polymer at the air-water interface are characterized by Langmuir isotherms and in situ X-ray reflectometry (XRR). The combination of the particles with a polymer leads to a stable polymer nanocomposite film at the air-water interface. XRR experiments show that nanoparticles are immersed in a thin polymer matrix of 2 nm. Using atomic force microscopy (AFM) on Langmuir-Blodgett films, we measure the lateral distribution of particles in the film. An analysis of single structures within transferred films results in fractal dimensions that are in excellent agreement with 2D simulations.