Nanometric Iron Oxide Research Articles

Fe3O4@SiO2 Magnetic Nanoparticles Modified with Cysteine: a New Adsorbent for Environmentally Friendly Adsorption/Desorption of Pb(II) ions

In recent years, nanoparticles have become the focus of scientific research because of their wide potential application value. Iron oxides show incredible magnetic saturation, stability, and intuitive properties on the surface, making them ideal for a variety of uses. In this paper, nanometer iron oxide particles are synthesized by co-deposition method, and silica is further used to avoid agglomeration. Functional synthesis of cysteine nanoparticles (FNMs-Cys).The optimum synthesis conditions and adsorption conditions were determined by orthogonal experiments. In addition, the anti-interference and regeneration cycle performance of FNMs-Cys are discussed. The samples were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), N2 adsorption and desorption automatic specific surface and porosity analyzer (BET), thermogravimetric analysis (TG) and hysteresis loop test (VSM). The adsorption process of Pb2+ by FNMs-Cys accords with quasi-second-order kinetics and Langmuir isothermal adsorption model, which shows that the adsorption is mainly through chemical adsorption of monolayer, In the Langmuir model, the maximum single-layer adsorption capacity of FNMs-Cys for Pb2+ reached 174.85 mg/g. After five cycles of adsorption-desorption regeneration, FNMs-Cys still showed good stability and recyclability. At present, it is of forward-looking significance to study the removal effect of Pb2+ in water by using amino acid modified mesoporous magnetic silica materials in laboratory.

Combustion behavior of single iron particles-part I: An experimental study in a drop-tube furnace under high heating rates and high temperatures

Micrometric spherical particles of iron in two narrow size ranges of (38–45) µm and (45–53) µm were injected in a bench scale, transparent drop-tube furnace (DTF), electrically heated to 1400 K. Upon experiencing high heating rates (104–105 K/s) the iron particles ignited and burned. Their combustion behavior was monitored pyrometrically and cinematographically at three different oxygen mole fractions (21%, 50% and 100%) in nitrogen. The results revealed that iron particles ignited readily and exhibited a bright stage of combustion followed by a dimmer stage. There was evidence of formation of envelope micro-flames around iron particles (nanometric particle mantles) during the bright stage of combustion. As the burning iron particles fell by gravity in the DTF, contrails of these fine particles formed in their wakes. Peak temperatures of the envelope flames were in the range of 2500 K in air, climbing to 2800 K in either 50% or 100% O2. Total luminous combustion durations of particles, in the aforesaid size ranges, were in the range of 40–65 ms. Combustion products were bimodal in size distribution, consisting of micrometric black magnetite particles (Fe3O4), of sizes similar to the iron particle precursors, and reddish nanometric iron oxide particles consisting mostly of hematite (Fe2O3).

Novel nano-ferromagnetic activated graphene adsorbent extracted from waste for dye decolonization

Polyethylene terephthalate (PET) waste was converted into graphene by pyrolysis, and the synthesized graphene (SG) was modified into activated graphene (AG) by potassium hydroxide (KOH) impregnation and nano-ferromagnetic activated graphene (NFMAG) by nanometric iron oxide coating via co-precipitation and external reduction method. The chemical, textural and structural properties of SG, AG and NFMAG were investigated using scanning electron microscope (SEM), transmission electron microscope (TEM), Brunauer Emmett Teller (BET) surface area analysis, energy dispersion X-rays spectroscopy (EDX), X-Ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. SG, AG and NFMAG exhibited microporous structures with high surface areas of 391.06, 460.01 and 319.62 m2 g−1 respectively. SG, AG and NFMAG were used in the removal of methylene blue (MB) dye from an aqueous solution. The effect of contact time, adsorbent dosage, initial solution pH, initial dye concentration and temperature were studied. The adsorption isotherms, kinetics and thermodynamics were investigated. A maximum monolayer adsorption capacity (qm) of 216.83, 348.30 and 291.78 mg g−1 were obtained for SG, AG and NFMAG respectively. AG and NFMAG showed superior adsorption capacity over their precursor SG due to the high surface area and surface chemistry. MB adsorption with all prepared adsorbents followed the pseudo-second-order kinetics model and Langmuir adsorption isotherm. The adsorption mechanisms were explained using FTIR, intraparticle diffusion and liquid-film diffusion. All MB-adsorbent systems were endothermic and spontaneous. The reusability of SG, AG and NFMAG was assessed for five adsorption cycles. NFMAG exhibited excellent stability and reusability due to its ease of magnetic separation.

Identification of magnetic enhancement at hydrocarbon-fluid contacts

Identifying the depths of the hydrocarbon-fluid contacts in a reservoir is important for determining hydrocarbon reserves and production planning. Using core samples from the Tay Sandstone reservoir in the central North Sea, we show that there is a magnetic enhancement at the hydrocarbon-fluid contacts that is detectable through both magnetic susceptibility measurements and magnetic hysteresis measurements. We observed this magnetic enhancement at both gas-oil and oil-water contacts, which have been independently identified using nonmagnetic methods; we did not consider gas-water contacts in this study. We demonstrate that this magnetic enhancement is caused by the precipitation of new nanometric iron oxide (magnetite) and iron sulfide (greigite) phases. The magnetic enhancement may be caused by diagenetic changes or preferential biodegradation at the top of the oil column during early filling and at the oil-water contact. Our findings have the potential to be used to identify paleo-hydrocarbon-fluid contact in both structurally modified fields and failed wells. The technique can also be used to infer the fill history of a basin and calibrate petroleum systems models. Magnetic susceptibility measurements have the advantage that they can easily and quickly be measured in the field on whole core material.

Specific Targeting MRI of Chitosan Oligosaccharide Modified Fe3O4 Nanoprobe on Macrophage and the Inhibition of Macrophage Foaming Induced by ox-LDL

Atherosclerosis (AS) is a primary cause of morbidity and mortality all over the world. Molecular imaging techniques can enable early localization and diagnosis of atherosclerosis plaques. Recent newly developed chitooligosaccharides (CSO) is considered to be capable of target mannose receptors on the surface of macrophages and to inhibit foam cell formation. Here we present a targeting magnetic resonance imaging (MRI) nanoprobe, which was successfully constructed with polyacrylic acid (PAA) modified nanometer iron oxide (Fe3O4) as the core, and coating with CSO molecules, possessing the abilities of targeted MRI and specifically inhibition of the formation of foamy macrophages in the atherosclerotic process. The experimental results showed that the distributions of PAA-Fe3O4 and CSO-PAA-Fe3O4 were uniform and the corresponding sizes were about 5.93 nm and 8.15 nm, respectively. The Fourier transform infrared spectra (FTIR) testified the CSO was coupled with PAA-Fe3O4 successfully. After coupled with CSO, the r1 of PAA-Fe3O4 was increased from 5.317 mM s-1 to 6.147 mM s-1, indicating their potential as MRI contrast agent. Oil Red O staining and total cholesterols (TC) determination showed that CSO-PAA-Fe3O4 could significantly inhibit the foaming process of RAW264.7 cells induced by oxidatively modified low density lipoprotein (ox-LDL). In vitro cellular MRI displayed that, compared with PAA-Fe3O4,CSO-PAA-Fe3O4 could lower the T1 relaxation time of RAW264.7 cells better. In summary, construction of CSO-PAA-Fe3O4 nanoprobe in this study could realize the targeted MRI of macrophages and inhibition of ox-LDL induced macrophage foaming process. This will provide a new avenue in the diagnosis and treatment of AS.

Different Nanomaterials for Soil Remediation Affect Avoidance Response and Toxicity Response in Earthworm (Eisenia fetida)

The application of nano-level passivating agents in the remediation of soil heavy metal pollution has received widespread attention, but its harm to soil animals should also be addressed. This study explored the effect of three nanomaterials-nanohydroxyapatite apatite (n-HAP), nano zeolite (n-zeolite), and nanometer iron oxide (n-Fe3O4), on catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content through filter paper contact test. The effects of nanomaterials spiked at 1.5%wt of soils on earthworm avoidance behavior were also be studied, and the crystallinity and surface charge of three nanomaterials were characterized. The results showed that the activities of CAT, SOD and POD and the content of MDA have been changed at different level. And earthworms have obvious avoidance behavior to the three kinds of nanomaterials. Therefore, nanomaterials do have adverse effects on earthworms, and their biological toxicity should be considered when selecting passivating agents for soil heavy metal pollution remediation.

Enhanced adsorption and catalytic degradation of organic dyes by nanometer iron oxide anchored to single-wall carbon nanotubes

Abstract Arc discharge method with Fe catalyst was used to prepare single-wall carbon nanotubes (SWCNTs) and there are an amount of iron nanoparticles formed tightly on SWCNTs. Nanometer iron oxide anchored to SWCNT composite (AO-Fe-SWCNTs) was obtained in situ by oxidizing the above as-grown SWCNTs (As-Fe-SWCNTs) in air at 375 °C. AO-Fe-SWCNTs exhibited an excellent performance of adsorption, Fenton and photo-Fenton degradation of methyl blue (MB) and methyl orange (MO) in aqueous solutions. Adsorption of MB and MO by AO-Fe-SWCNTs could reach equilibrium within 10 min and its maximum adsorption capacity for MB and MO was up to 256.69 mg g−1 and 93.58 mg g−1, respectively. MB could almost be decomposed within 10 min depending on their concentration using AO-Fe-SWCNTs as catalyst under the assistance of H2O2. UV–Vis light irradiation further speeded up the above Fenton reaction and the degradation of MB and MO in solutions. It was revealed that the small sizes of iron oxides (several nanometers) and their good dispersion on SWCNTs are the main reason responsible for the good property of AO-Fe-SWCNTs. Furthermore, iron oxides-SWCNTs heterojunctions probably improve electron-hole separation during irradiation and promote the generation of hydroxyl radicals. The present study indicates that AO-Fe-SWCNTs with firm web structure are a promising material for adsorption and degradation of organic dyes.

Arsenic removal from water by nanometer iron oxide coated single-wall carbon nanotubes

Single-wall carbon nanotubes (SWCNTs) were prepared by arc discharge evaporation of a carbon electrode containing Fe catalyst so that there are an amount of iron nanoparticles attached tightly on SWCNTs. The iron oxide nanoparticle coated SWCNT composite was prepared in situ by oxidizing the above as-grown SWCNTs in air at 350°C, which was used as an adsorbent for As5+ removal from water. It was found that the maximum As5+ adsorption capacity of the composite was 42.30mgg−1 at pH8 and 49.65mgg−1 at pH4, respectively. The kinetics data were best fitted with a pseudo-second order, thus suggesting chemical adsorption on the surface and pores of iron oxide nanoparticles. The adsorption isotherm obtained at pH8 was best fitted to the Freundlich model, therefore a non-ideal adsorption on heterogeneous surfaces for As5+ ions on iron oxide nanoparticles was proposed. The firm web structure with high adsorption capacity makes the composite a promising adsorbent for arsenic removal in contaminated water.

Size-Dependent Phase Map and Phase Transformation Kinetics for Nanometric Iron(III) Oxides (γ → ε → α Pathway)

Nanometric iron(III) oxide has been of great interest in a wide range of fields due to its magnetic properties, eminent biochemical characteristics, and potential for technological applications. Among iron oxides, e-Fe2O3 is considered as a remarkable phase due to its giant coercive field at room temperature and ferromagnetic resonance capability. Here we present the first size-dependent phase map for e-Fe2O3 via a γ → e → α pathway together with the activation energies for the phase transformations, based on X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). HRTEM images of e-Fe2O3 nanocrystals show both inversion and pseudohexagonal twins, which are fundamentally important for understanding the correlation between its nanostructure and magnetic properties. Two activation energies for γ-Fe2O3 → α-Fe2O3 phase transformations are 186.37 ± 9.89 and 174.58 ± 2.24 kJ mol–1, respectively. The results provide useful information about the size, crystal structure, and tra...

Bismuth labeling for the CT assessment of local administration of magnetic nanoparticles

Many therapeutic applications of magnetic nanoparticles involve the local administration of nanometric iron oxide based materials as seeds for magnetothermia or drug carriers. A simple and widespread way of controlling the process using x-ray computed tomography (CT) scanners is desirable. The combination of iron and bismuth in one entity will increase the atenuation of x-rays, offering such a possibility. In order to check this possibility core–shell nanocrystals of iron oxide@bismuth oxide have been synthesized by an aqueous route and stabilized in water by polyethylene glycol (PEG), and we have evaluated their ability to generate contrast by CT and magnetic resonance imaging (MRI) to measure the radiopacity and proton relaxivities using phantoms. High-resolution scanning transmission electron microscopy (STEM) revealed that the material consists of a highly crystalline 8 nm core of maghemite and a 1 nm shell of bismuth atoms either isolated or clustered on the nanocrystal’s surface. The comparison of μCT and MRI images of mice acquired in the presence of the contrast shows that when local accumulations of the magnetic nanoparticles take place, CT images are more superior in the localization of the magnetic nanoparticles than MRI images, which results in magnetic field inhomogeneity artifacts.

Low Resistance, Carbon Black-free Magnetite Anode for Li-ion Batteries Obtained by One-step Attachment of Carbon Nanotubes

The paper describes a simple, one-step synthetic route for the fabrication of nanometric iron (III) oxide attached to multiwalled carbon nanotubes (MWCNT). TEM images show that magnetite nanoparticles with primary particle sizes of ca. 10 nm are preferentially located on the outer walls of carbon nanotubes. The obtained nanocomposites have been examined on reversible electrochemical insertion of lithium cations in a Li-ion cell. The presence of MWCNT brings about a substantial increase of the magnetite reversible capacities in the absence of any additional carbonaceous conductivity enhancing agent. With increasing MWCNT content in the material, reversible capacity consistently rises from 207 mAhg-1 for pure iron (III) oxide up to 763 mAhg-1 for the composite with 40 % of MWCNT. Cyclic voltammetry measurements reveal the expected large hysteresis between the reduction and oxidation peaks associated with Li+ insertion/deinsertion into magnetite crystal lattice. The reductive current peak maxima steadily rise with increasing MWCNT content from 0.15 A g-1 for pure iron (III) oxide up to 0.4 A g-1 for the composite with 40 % of MWCNT which confirms faster kinetics of electrochemical processes. EIS measurements directly proved the internal resistance decrease connected with the incorporation of MWCNT.

Laser Synthesis of Nanometric Iron Oxide Films with High Seebeck Coefficient and High Thermoelectric Figure of Merit

Radiation of a KrF-laser (λ = 248 nm) was used for the synthesis by reactive pulsed laser deposition (RPLD) of nanometric iron oxide [Fe2O3-X (0≤×≤1)] films with variable thickness, stoichiometry and electrical properties. Film deposition was carried out on <100>Si at its temperature to have being increased from 293 to 800 K. XRD analysis showed that films deposited on Si substrate had polycrystalline structure. Films demonstrated semiconductor temperature trend with variable band gap Eg about 1.0 eV or less depending on oxygen pressure, the number of laser pulses and substrate temperature. Film thickness (13–60 nm) depended on oxygen pressure, substrate temperature and number of laser pulses. The higher substrate temperature, the more crystallinity of the deposited iron oxides’ films was resulting in increasing of thermo electromotive force coefficient (Seebeck coefficient, S). It was found out the optimum oxygen pressure in the reactor, substrate temperature and film thickness when the S coefficient was high as 12–4 mV/K in the range 240–330 K. The thermoelectric figure of merit (ZT) was high as 1–6 in the range 280–330 K. This makes nanometric Fe2O3-X films, synthesized by UV photons using RPLD method, an exceptionally strong candidate for effective thermo sensors and thermo converters operating at moderate temperature.

Laser synthesis of nanometric iron oxide films for thermo-sensing applications

KrF* excimer laser pulses of 248nm were used for the synthesis of nanometric iron oxide films with variable thickness, stoichiometry and electrical properties. Film deposition was carried out on <100> Si and SiO2 substrates. The number of laser pulses was increased from 4000 to 6000, while ambient reactive oxygen pressure varied from 0.1 to 1.0Pa. The film thickness depends on oxygen pressure, number of laser pulses and substrate nature. All films demonstrated semiconducting temperature behaviour with variable band gap (Eg) depending on oxygen pressure, substrate nature and temperature. Eg value was less than 1.0eV for all deposited films. XRD analysis evidenced that films deposited on Si substrate have polycrystalline structure, while films deposited on SiO2 were amorphous. The higher oxygen pressure, the lower crystallinity of the deposited film was observed, resulting in change of thermo electromotive force coefficient (S) value. For larger substrate temperature, a better crystallization was observed in the deposited films, resulting in increased S coefficient value. The largest value of the S coefficient was about 8.7mV/K in the range 290–295K and it decreased to 1.0–1.6mV/K when heating temperature changed from 240 to 330K. The figure of merit of deposited structures was ZT=3–6 in the range 240–330K with a maximum of 12 at 300–304K. We have shown that thermo-sensing characteristics of the films strongly depend on their electrical and structural properties.

Micro-investigation of EPICA Dome C bottom ice: evidence of long term in situ processes involving acid–salt interactions, mineral dust, and organic matter

The EPICA Dome C ice core (EDC) reached a final depth of 3260 m, at a maximum height of about 15 m above the ice–bedrock interface in December 2004. We present here data gained from a detailed investigation of selected samples of the deeper part of the core located below 3200 m and referred to as bottom ice. This part of the core has been poorly investigated so far mainly because there are significant challenges in interpreting paleo-records that were very likely modified by long term in situ processes. Our study combines high resolution ion chromatography, high resolution synchrotron X-Ray micro-fluorescence (micro XRF), scanning, and transmission electron microscopy. Our aim was to identify the long term physico-chemical processes at work close to the bedrock, to determine how they have altered the initial registers, and, ultimately to extract information on the very ancient Antarctic environment.The ubiquitous presence of nanometer iron oxide crystals at the surface of wind-borne dust aggregates containing also large amount of organic matter raises the possibility that the consolidation of windborne dust clusters formed during ice recrystallization could be related to microbial iron reduction and, thus, to the progressive reactivation of dormant bacterial activity in warming ice. Inclusions of size and number density increasing with depth observed in the 12 last meters (3248–3260 m) contain liquid and solid species, among them marine biogenic acids, numerous wind-borne dust aggregates and clusters of large reversible calcium carbonate particles precipitated once the inclusion was formed and often covered by secondary gypsum. The refreezing of slush lenses is discussed as a potential cause of the formation of such heterogeneous and complex mixtures. In addition to the very fine micrometer size minerals windborne from extra-Antarctic continental sources and often accreted in large aggregates, single medium size particles (a few to ca 20 μm and among them organic debris) are commonly encountered. Their size, surface shape, and mineralogy suggest that aerosol transport from Antarctic ice-free areas played a significant role at the time EDC bottom ice was formed. Concentrations and concentration ratios of biogenic sulfur species also advocate for the strengthening of peri-Antarctic meteorological patterns that favor the inland penetration of disturbed flow carrying local material. Very large well preserved mineral particles several tens of micrometers in diameter, and biotope relics in deeper ice close to 3260 m likely come from the sub-glacial environment.

The competing effect of ammonia in the synthesis of iron oxide/silica nanoparticles in microemulsion/sol–gel system

Combined microemulsion/sol–gel processes may be used to prepare composite nanoparticles. In this work, iron oxide/silica nanoparticles were synthesized in such a combined system, having ammonium hydroxide acting in both processes: as precipitating agent in the synthesis of iron oxide and as catalyst in the sol–gel process of silica. The nanoparticles were synthesized in microemulsions containing tetraethoxysilane (TEOS) and composed by Triton X-100/hexyl alcohol/cyclohexane/aqueous solution, with different amounts of ammonium hydroxide. Powder materials were obtained after centrifugation, washing and drying, and they were analyzed as synthesized and after heating at 350, 500 and 1000°C. The influence of base quantity was evaluated in relation to the size of the particles and the iron oxide phase synthesized. TEM analysis showed that nanometric iron oxide particles were formed and that they were percolated by a net of amorphous silica. The higher amount of ammonia seems to have induced TEOS condensation process instead of iron oxide particles’ growth, indicating that the quantity of base influenced both the microemulsion system and the sol–gel process, but with minor influence over the iron oxide composition, as evidenced by FT-IR and DRX.

Correction to Polymorphous Transformations of Nanometric Iron(III) Oxide: A Review

Correction to Polymorphous Transformations of Nanometric Iron(III) Oxide: A Review

Synthesis of nanometric iron oxide films by RPLD and LCVD for thermo–photo sensors

Iron oxide films were deposited on Si substrates by reactive pulsed laser deposition (RPLD) using a KrF laser (248 nm). These films were deposited too by laser (light) chemical vapor deposition (LCVD) using continuous ultraviolet photodiode radiation (360 nm). The deposited films demonstrated semiconducting properties. These films had large thermo-electromotive force (e.m.f.) coefficient (S) and high photosensitivity (F). For films deposited by RPLD the S coefficient varied in the range 0.8–1.65 mV/K at 205–322 K. This coefficient depended on the band gap (E g ) of the semiconductor films, which varied in the range 0.43–0.93 eV. The largest F value found was 44 Vc/W for white light at power density I≅0.006 W/cm2. Using LCVD, iron oxide films were deposited from iron carbonyl vapor. For these films, the S coefficient varied in the range −0.5 to 1.5 mV/K at 110–330 K. The S coefficient depended on E g of the semiconductor films, which varied in the range 0.44–0.51 eV. The largest F value of these films was about 40 Vc/W at the same I≅0.006 W/cm2. Our results showed that RPLD and LCVD can be used to synthesize iron oxide thin films with variable stoichiometry and, consequently, with different values of E g . These films have large S coefficient and high photosensitivity F and therefore can be used as multi-parameter sensors: thermo–photo sensors.

Flame retardant biocomposites: Synergism between phosphinate and nanometric metal oxides

The known flame-retardant synergism between phosphorus-based additives and metal oxides, already used for petroleum-based plastics, has been extended to bio-based materials. The pyrolysis and the flame-retardancy properties of aluminium phosphinate (AlPi) in combination with nanometric iron oxide and antimony oxide on a poly(3-hydroxy-butyrate-co-3-hydroxyvalerate)/poly(butylene adipate-co-terephthalate) (PHBV/PBAT) blend were investigated. Better fire retardancy, ascribed to increases in intermediate char, favoured improvements in the UL 94 classification. Both the phosphorus and the nanofiller components participate simultaneously in the flame-retardancy mechanism: the first acting as flame inhibition in the gas phase, and the second promoting cross-linking in the solid phase. Redox reactions between iron oxide and the phosphinate additive were confirmed by XRD analysis and provided further evidence of the activity of metal compounds.

Structural, electrical, and optical characterizations of laser deposited nanometric iron oxide films

The structural, electrical, and optical characteristics of nanometric Fe2O3−x films fabricated on ⟨100⟩ Si and SiO2 substrates by ablating an iron target with a KrF excimer laser in low pressure (0.05–1.0 Pa) O2 atmosphere are reported. The thickness of films fabricated with 4000 laser pulses is ∼80 nm for samples deposited at the lowest pressure (0.05 Pa) and decreases gradually to 50 nm at the highest used pressure (1.0 Pa). The film mean composition results close to FeO at lower pressures (0.05–0.10 Pa) and to Fe2O3 at higher pressures (0.5–1.0 Pa). From glazing incidence x-ray diffraction spectra, it was inferred that deposits are poorly crystallized, especially the ones prepared at relatively high oxygen pressures (0.5–1.0 Pa). Scanning electron microscopy inspections show that surfaces are plane and uniform, with very rare (&amp;lt;0.1 μm−2) submicron droplets. From x-ray reflectivity spectra, surface roughness results very low (0.1–0.5 nm, increasing with O2 pressure). The films present a semiconductor behavior, with electrical energy gaps increasing from 0.43 to 0.93 eV with increasing O2 pressure, while the optical energy gap varies from 1.60 eV (0.05 Pa) to 1.74 eV (1.0 Pa). Very high thermoelectromotive force coefficient values were measured (up to 1.65 mV/K). It is also shown that films present promising gas sensing properties.

Growth of carbon nanotubes through selective deposition of nanoparticles

This paper describes the selective growth of a high density of Carbon NanoTubes (CNTs) (up to 2.5 1011 CNT cm−2) in nanometric (140 to 300 nm) holes etched in silicon dioxide (vias). The method involves (i) the electrografting of a thin layer of poly(hydroxyethyl methacrylate) (polyHEMA) at the Si bottom of the SiO2 vias; (ii) independent synthesis of nanometric iron oxide nanoparticles (NP) by the polyol method, the NPs being capped by diethylene glycol (DEG); (iii) HF cleaning of the SiO2 structure; (iv) selective deposition of the NPs on the polyHEMA layer at the bottom of the vias; (v) burn-off of the polymer; (vi) Chemical Vapour Deposition (CVD) growth of the CNTs. The success of the experiment is based on the fine tuning of the selective interactions between the capping of the NPs and the polymer deposited exclusively at the bottom of the vias.