Presentation of the equipment for processing and ... Makovec...Equipment Laboratory for the...
40
50 nm Monodisperse nanoparticles of maghemite Presentation of the equipment for processing and characterization of nanoparticles, of the magnetometer, and of their possible applications Darko Makovec Department for Materials Synthesis Jožef Stefan Institute
Transcript of Presentation of the equipment for processing and ... Makovec...Equipment Laboratory for the...
50 nm
Monodisperse nanoparticles of maghemite
Presentation of the equipment for processing and characterization of
nanoparticles, of the magnetometer, and of their
possible applications
Darko Makovec
Department for Materials SynthesisJožef Stefan Institute
Equipment
Laboratory for the processing and characterization of nanoparticles equipped with fume hoods and with basic laboratory equipment.
• Autoclave (Parr 4641, volume 1 L ) for hydrothermal synthesis of nanoparticles.
• Dynamic light-scattering granulometer (Fritsch ANALYSETTE 12 DynaSizer) for measurements of the particle size in suspensions.
Vibrating-sample magnetometer (LakeShore 7404VSM) for magnetic measurements at room temperature.
The equipment of the Nanocenter supplements the equipment available in the laboratory for the processing and characterization of nanoparticles at the Department for Materials Synthesis, Jožef Stefan Institute.
Autoclave (Parr 4641)
Autoclave used for hydrothermal/sovothermal synthesis under high pH.
Autoclave vessel (volume 1 L) • used with bench-top furnace available at K8.• Inconel 600 alloy resistant against high pH (not for chlorides!).
• max. pressure 131 barr at 350 oC.• equipped with manometer, two safety valves, andset of valves for flushing the vessel with (inert) gas.
Hydrothermal synthesisHydrothermal: chemical reactions occur in aqueous solutions above 100 oC under increased pressure, usually equilibrium water pressure.
Supercritical: at temperatures above critical point (374 oC, 218 barr)
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Max. pressure 131 barr
Max. temperature ≈ 330 oC
Dynamic light-scattering granulometer(ANALYSETTE 12 DynaSizer)
Measurements of particle size (hydrodinamic) in suspensions.
Equipped with peristatic pump for sampling (on-line measurements).
Dynamic light-scatteringFrom Wikipedia, the free encyclopedia
Dynamic light scattering can be used to determine the size distribution profile of small particles in suspensions.
Brownian motion is probed with scattering of monchromatic, cohetent laser light. Brownian motion causes a time-dependent fluctuation in the scattering intensity, because the distance between the scatterers in the suspension is constantly changing with time. The scattered light undergoes either constructive or destructive interference by the surrounding particles and within this intensity fluctuation.Information is contained about the time scale of movement of the scatterers.
The dynamic information of the particles is derived from an autocorrelation of the recorded intensity trace during the experiment.
Hypothetical Dynamic light scattering of two samples: Larger particles vs. smaller particles.
Dynamic light-scattering granulometer(ANALYSETTE 12 DynaSizer)
Measurement Range: 1 nm to 6000 nmPrinciple of Operation: Dynamic Light Scattering in backward direction (135 o).Measurement of diluted, concentrated, dark or black suspensions with monodisperse or polydisperse suspension
Dynamic light-scattering granulometer(ANALYSETTE 12 DynaSizer)
Concentration Range 0,001 to 40 wt%Laser source: Single Mode Laser with optical fibre(wavelength 658 nm, Adjustment of Laser power from 1mW up to 75mW)Optical Cell Integrated into the instrument (no consumables like cuvette).Small volume: less then 50 μlSample temperature controlled by pettier element: 15°C up to 70°C
Patented design for concentrated or opaque/dark samples.High concentration sample are measured using a very thin layer. Multi diffusion and absorption of the laser beam intensity (local warm up effect of the sample – gradient index) are eliminated. Using a ticker sample layer allows the measurement of low concentrations down to 0,001wt/%
Dynamic light-scattering granulometer(ANALYSETTE 12 DynaSizer)
Correlator: Autocorrelation 1000 channels, 16 bits, 100ns pulse width correlation
Software: Different calculation algorithms included:CONTIN (Monomodal),CUMULANT (Monodisperse / avarage size – polydispersity index), PADÈ LAPLACE (unique proprietary algorithm developed for polydisperse suspensions / high resolution) Multi acquisition for statistical measurement possible . This yields the possibility to determine complete size distributions.
Vibrating-sample magnetometer (LakeShore 7404 VSM)
mCU ⋅=ind
C- cal. constantm- mag. moment
gemu ionmagnetizat mass
,mass
momentM =
thin-film holders
side-mountedbottom-mountedbulk
sample holders
liquid
Vibrating-sample magnetometer (LakeShore 7404 VSM)
Moment range: 1x10-7 to 103 emuApplied field strength:
air gap1.53 T29 mm air gap
16 mm sample access
1.81 T23 mm air gap10 mm sample access
2.17 T16.2 mm air gap3.6 mm sample access
Field
H
N Θ
Θ range: 00 to 3600
Equipment location:Department for Materials Synthesis, Jožef Stefan Institute (Ground floor K800)
Equipment accessibility:
In agreement with responsible person.
Responsible persons:Laboratory: Prof. Darko Makovec([email protected])
Autoclave:Bernarda Anželak([email protected])
DLS:Slavko Kralj([email protected])
VSM magnetometerDr. Sašo Gyergyek([email protected])
Department for Materials Synthesis
Microwave materials:
Magnetic materials: Semiconducting materials: Magnetic nanoparticles:
Ferrofluids, nanoparticles forbiomedical applications
Absorbers, nonreciprocaldevices (circulators)
Hexaferrites (BaFe12O19)
Ceramics, thick films
Spinel ferrites (Fe3O4, CoFe2O4, …)
Nanoparticles, suspensions
Semiconducting, ferroelectricceramics, photocatalytic nanoparticles
PTCR ceramics, photocatalytic nanoparticles:
TiO2, ZnO, BaTiO3, high Tcferroelectrics, …
Nanoparticles, ceramics
Multifunctional materials:(Nano)composite materials combining different (coupled) functional properties, magnetic photocatalysts, magnetodielectrics, multiferroics, etc.
Aggregates of magnetic (Fe2O3) and photocatalitic (TiO2) nanoparticles, solid materials combining ferrites and ferroelectrics, ferrites and dielectrics, ...
Aggregation of different nanoparticles into nanocomposite particles in suspensions, sintering into composite ceramics, dispersing nanoparticles into polymer, silica matrixes, …
Superparamagnetic nanoparticlesSyntheses of nanoparticles (spinel ferrites, hexaferrites, magnetic perovskites, alloys, …): Coprecipitation, coprecipitation in microemulsions, hydrothermal synthesis, sonochemicalsynthesis, sol-gel, ...
Ferrofluids (stable suspensions of superpramagnetic nanoparticles in a carrier liquid): Nonpolar, polar (water) carrier liquids, different surfactantasStability of ferrofluids, magnetoreology, magnetic properties,....
Nanoparticles for biomedical applications:Functionalization of magnetic nanoparticles (silika, silanes, polymers)Nanoparticles for hyperthermia (perovskites with tuned Currie temperature, composite nanoparticles spinel ferrite-hexaferrite )
Nanocomposites: Homogeneously dispersed nanoparticles in matrixes of silica or polymer, nanocomposite particles, multifunctional nanocomposites - magnetodielectrics, multiferroics, magneticphotocatalysts…
Si
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Synthesis of (magnetic) nanoparticles
Hydrothermal synthesisHexaferrite BaFe12O19
Coprecipitation in microemulsionsSpinel ferrites (maghemite) Thermal decomposition of
organometallic complexesSpinel ferrites (CoFe2O4)
Coprecipitation from aqueous solutionsSpinel ferrites (maghemite)
Superparamagnetic nanoparticles of BaFe12O19 hexaferrite were synthesized for the first time
Department for Materials Synthesis (and Characterization)
Synthesis of superparamagnetic nanoparticles of hexaferrites, preparation of ferrofluids.
Nanoparticles synthesis
BaFe12O19
SrFe12O19
Suspensions
Magnetic nanoparticles – ferrofluids …
Magneto-rheology
Application of magnetic nanoparticles in biomedicine
Basic concept:• Selective bonding of bioactive molecules (therapeutic agents, targeting
ligands, fluorescent dyes, ….) to the surface of magnetic nanoparticles (size approx. 10 nm) via a functionalization layer.
• Manipulation and detection from distance. Using external magnetic field, the nanoparticles can be concentrated in a desired part of human body, they can be tracked through their magnetic properties, they can be used to heat a tissue, …
Magnetic nanoparticle
Therapeutic agent, marker, dye, …
Functionalization molekule
Si
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Applications of magnetic nanoparticles in diagnostics
• Separation/detection of bioactive molecules (in vitro)• Magnetorelaxometry (in vitro)• Detection of nanoparticles marked with targeting ligands
(e.g. antibodies) using measurements of magnetic properties (in vivo)
• NMR contrast enhancement (in vivo)
• ….
NMR image of magnetic nanoparticles in a targeted part of mice brainsPiotr Walczak and Jeff Bulte
Detection using magnetic probe:100 μg of nanoparticles at the distance of 30 cmEndomagnetics
Department for Materials Synthesis
Magnetic nanoparticles – application in therapy• Magnetic hyperhermia• Targeted drug delivery
Magnetic nanoparticles internalizedinto cells
Nanoparticles
Siemens AG, Pictures of the future 01/2007
FunctionalizationGrafting functionalization molecules onto the nanoparticles’ surfaces to provide specific functional groups for further bonding of functional molecules.
Functionalization molecules:Molecules with at least-two functional groups:- First functional group interacts with the nanoparticle’s surface, - Second functional group provides reactive site for further surface reactions
with “functional molecules needed in application”.
Functional molecules: (Bio)molecules needed in application.
Si
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Nanoparticle
Biocompatible layer
Fuctional molecule, therapeutic agent, marker, dye, …
Functionalization molecule
Functionalized magnetic nanoparticles for biomedical applications
Active sites for selective bonding of different (bio)molecules to the nanoparticle’s surface:
• Biocompatible polymers (e.g. dextrane, PEG, to increase blood circulation times),
• Therapeutic agents, drugs,
• Targeting ligands (e.g. antibodies, for targeting tumour tissue),
• Fluorescent dyes (for tracking using optical methods),
• Permeation enhancers,• …
Biocompatible layer
Magnetic core
Abtibody
Therapeutic agent
Coating magnetic nanoparticles with silicaThin layer of silica provides surface silanol OH- groups for further bonding of functionalization molecules. It also provides high negative surface charge and thus ensures colloidal stability.
Hydrolysis and polycondensation of tetraethyl orthosilicate (TEOS) in stable aqueoussuspension of magnetic nanoparticles in presence of alkaline catalyst (ammonia, KOH).
Layer of silica
Coating magnetic nanoparticles with silicaControl of suspension stability and thickness of silica layer using DLS.
Grafting of silane molecules onto magnetic nanoparticles
Bonding amino- silane to surface OH groups of silica for amino functionalization.
Control of the NH2 surface concentration:
APS
APMS
Aminopropyl triethoxy silane
(aminoethylamino)propyltriethoxy silane
Grafting of silane molecules onto magnetic nanoparticles
Agglomeration in the suspensions of APS-grafted maghemite nanoparticles.
APS
Aminopropyl triethoxy silane
TEM size 13.7 ± 2.9 nm
Development of new methods for binding of bioactive molecules (chromophores, therapeutic agents, monoclonal antibodies) onto the functionalised nanoparticles.
R&D cooperation with Nanotesla Institute Ljubljana
Magnetic properties of nanoparticles:
Decrease in “saturation” magnetization
influence of large surface area
Zero corcivity = superparamagneticity
size effect
Coarse-grained maghemite powder Maghemite nanoparticles, ~ 13 nm in size
Maghemite nanoparticles, ~ 3 nm in size
Magnetic propertiesMagnetic nanoparticles are used in the form of stable colloidal suspensions. The (magnetic) agglomeration should be prevented.
Superparamagnetic nanoparticles
Without the influence of external magnetic field, the superparamagnetic nanoparticles do not show any coercivity – no magnetic interactions.
Paramagnetic Ferromagnetic Superparamagnetic
Magnetic separation
Magnetic nanoparticles – magnetic separations, purifications, selection, …
Magnetic nanoparticle
Functionalization layer
Functionalization molecule
Magnetic separationForce acting on the magnetic particle in a mag. field gradient :
Fm = μ0 Vp Mp H
Magnetic-field gradientParticle magnetization
Particle volume ∝ d3
Δ
The force acting on the superparamagnetic nanoparticle is too weak for effective separation.
Stable suspension of thesuperpramagnetic nanoparticles.
Suspension of the clusters of thesuperpramagnetic nanoparticles.
Controlled clustering
Mixing the suspension of the nanoparticles coated with citric acid (0.005 %, pH = 9.0) in the suspension of the nanoparticles coated with APS (0.05 %, pH = 4.0) under agitation with ultrasound. pH after mixing = 5 – 7.
Nanoparticles coated with citric acid
Nanoparticles coated with APMS
Synthesis of superparamagnetic, photocatalytic particles for decomposition of organic pollutants in water.
The immobilization of the photocatalysts on magnetic carriers, to allow elimination of the photocatalyst from the water suspensionafter cleaning using an external magnetic field
R&D cooperation with Cinkarna Celje
Hetero-agglomeration of anatase nanoparticles and magnetic clusters in aqueous suspensions
Direct precipitation of anatase nanoparticles onto the magnetic clusters
Magnetic properties of superparamagnetic, photocatalytic particles.
R&D cooperation with Cinkarna Celje
Superparamagnetic polymer nanocomposites
Preparation of composite containing high content of dispersed magnetic nanoparticles:
Dispersing hydrophobisednanoparticles in decane, addition of methyl methacrylate monomer,precipitation polymerization.
oleic acid
Dispersing hydrophobised nanoparticlesdirectly in methyl methacrylate monomer, polymerization in miniemulsion.
ricinoleic acid
Bonding initiator onto the nanoparticles,triggering polymerisation at the nanoparticles.
50 nm
Cooperation with M. Huskić, National institute of chemistry
Department for Materials Synthesis
Asst. Prof. Darja LisjakMagnetic materials for applications at very high frequencies
Circulators
Absorbers
Thermal coating of absorber layers Electrophoretic deposition
Car collision-avoidance systems
Electrophoretic deposition of hexaferrite
Electrophoretic deposition of thick films of hexaferrite (nano)particles from suspensions for applications in mm-wave nonreciprocal devices:
Thick filmSuspension of nanoparticles
Magnetophoretic deposition of hexaferrite
Deposition of structured layers of magnetic particles using magnetic field:
S. Kolev
M
Magnetic properties of oriented BaFe12O19 film measured in two directions
Θ=00
Θ=900
Electrophoretic deposition of hexaferrite
Nanocenter Equipment at K8Laboratory for the processing and characterization of nanoparticles equipped with fume hoods and with basic laboratory equipment.
• Autoclave (Parr 4641, volume 1 L ) for hydrothermal synthesis of nanoparticles.
• Dynamic light-scattering granulometer (Fritsch ANALYSETTE 12 DynaSizer) for measurements of the particle size in suspensions.
Vibrating-sample magnetometer (LakeShore 7404VSM) for magnetic measurements at room temperature.
Prof. Darko Makovec([email protected])
Bernarda Anželak([email protected])
Slavko Kralj([email protected])
Dr. Sašo Gyergyek([email protected])
