Hielscher – Ultrasound Technology

Power Ultrasound for Particle Treatment: Application Notes

To express their characteristics completely, particles must be deagglomerated and evenly dispersed so that the particles’ surface is available. Powerful ultrasound forces are known as reliable dispersing and milling tools that beak particles down to submicron- and nano-size. Furthermore, sonication enables to modify and functionalize particles, e.g. by coating of nano-particles with a metal-layer.

Find below a selection of particles and liquids with related recommendations, how to treat the material in order to mill, disperse, deagglomerate or modify the particles using an ultrasonic homogenizer.

How to Prepare your Powders and Particles by Powerful Sonication.

In alphabetical order:

Aerosil

Ultrasonic application:
Dispersions of Silica Aerosil OX50 particles in Millipore-water (pH 6) were prepared by dispersing 5.0 g of powder into 500 mL of water using a high intensity ultrasonic processor UP200S (200W; 24kHz). The silica dispersions were prepared in distilled water solution (pH = 6) under ultrasonic irradiation with the UP200S for 15 min. followed by vigorous stirring during 1 h. HCl was used to adjust the pH. Solid content in the dispersions was 0.1% (w/v).
Device Recommendation:
UP200S
Reference/ Research Paper:
Licea-Claverie, A.; Schwarz, S.; Steinbach, Ch.; Ponce-Vargas, S. M.; Genest, S. (2013): Combination of Natural and Thermosensitive Polymers in Flocculation of Fine Silica Dispersions. International Journal of Carbohydrate Chemistry 2013.

Al2O3-water Nanofluids

Ultrasonic application:
Al2O3-water nano fluids can be prepared by following steps: First, weigh the mass of Al2O3 nanoparticles by a digital electronic balance. Then put
Al2O3 nanoparticles into the weighed distilled water gradually and agitate the Al2O3-water mixture. Sonicate the mixture continuously for 1h with an ultrasonic probe-type device UP400S (400W, 24kHz) to produce uniform dispersion of nanoparticles in distilled water.
The nanofluids can be prepared at different fractions (0.1%, 0.5%, and 1%). No surfactant or pH changes are needed.
Device Recommendation:
UP400S
Reference/ Research Paper:
Isfahani, A. H. M.; Heyhat, M. M. (2013): Experimental Study of Nanofluids Flow in a Micromodel as Porous Medium. International Journal of Nanoscience and Nanotechnology 9/2, 2013. 77-84.

Bohemite coated silica particles

Ultrasonic application:
Silica particles are coated with a layer of Boehmite: To obtain a perfectly clean surface without organics, the particles are heated to 450°C. After grinding the particles in order to break up the agglomerates, a 6 vol% aqueous suspension (≈70 ml) is prepared and stabilized at a pH of 9 by adding three drops of ammonium-solution. The suspension is then deagglomerated by an ultrasonication with an UP200S at an amplitude of 100% (200 W) for 5 min. After heating the solution to above 85°C, 12.5 g of aluminum sec-butoxide were added. The temperature is kept at 85-90°C for 90 min., and the suspension is stirred with a magnetic stirrer during the whole procedure. Afterwards, the suspension is kept under continuous stirring until it is cooled down to below 40°C. Then, the pH value were adjusted to 3 by adding hydrochloric acid. Immediately afterwards, the suspension is ultrasonicated in an ice-bath. The powder is washed by dilution and subsequent centrifugation. After removal of the supernatant, the particles are dried in a drying oven at 120°C. Finally, a heat treatment is applied to the particles at 300°C for 3 hours.
Device Recommendation:
UP200S
Reference/ Research Paper:
Wyss, H. M. (2003): Microstructure and Mechanical Behavior of Concentrated Particle Gels. Dissertation Swiss Federal Institute of Technology 2003. p.71.

Cadmium(II)-thioacetamide nanocomposite synthesis

Ultrasonic application:
Cadmium(II)-thioacetamide nanocomposites were synthesized in the presence and absence of polyvinyl alcohol via sonochemical route. For the sonochemical synthesis (sono-synthesis), 0.532 g of cadmium (II) acetate dihydrate (Cd(CH3COO)2.2H2O), 0.148 g of thioacetamide (TAA, CH3CSNH2) and 0.664 g of potassium iodide (KI) were dissolved in 20mL double distilled deionized water. This solution was sonicated with a high-power probe-type ultrasonicator UP400S (24 kHz, 400W) at room temperature for 1 h. During the sonication of the reaction mixture the temperature increased to 70-80degC as measured by an iron–constantin thermocouple. After one hour a bright yellow precipitate formed. It was isolated by centrifugation (4,000 rpm, 15 min), washed with double distilled water and then with absolute ethanol in order to remove residual impurities and finally dried in air (yield: 0.915 g, 68%). Dec. p.200°C. To prepare of polymeric nanocomposite, 1.992 g of polyvinyl alcohol was dissolved in 20 mL of double distilled deionized water and then added into the above solution. This mixture was irradiated ultrasonically with the UP400S for 1 h when a bright orange product formed.
The SEM results demonstrated that in presence of PVA the sizes of the particles decreased from about 38 nm to 25 nm. Then we synthesized hexagonal CdS nanoparticles with spherical morphology from thermal decomposition of the polymeric nanocomposite, cadmium(II)- thioacetamide/PVA as precursor. The size of the CdS nanoparticles was measured both by XRD and SEM and the results were in very good agreement with each other.
Ranjbar et al. (2013) also found that the polymeric Cd(II) nanocomposite is a suitable precursor for the preparation of cadmium sulfide nanoparticles with interesting morphologies. All results revealed that ultrasonic synthesis can be employed successfully as a simple, efficient, low cost, environmentally friendly and very promising method for the synthesis of nanoscale materials without a need for special conditions, such as high temperature, long reaction times, and high pressure.
Device Recommendation:
UP400S
Reference/ Research Paper:
Ranjbar, M.; Mostafa Yousefi, M.; Nozari, R.; Sheshmani, S. (2013): Synthesis and Characterization of Cadmium-Thioacetamide Nanocomposites. Int. J. Nanosci. Nanotechnol. 9/4, 2013. 203-212.

CaCO3

Ultrasonic application:
Ultrasonic coating of nano-precipitated CaCO3 (NPCC) with stearic acid was carried out in order to improve its dispersion in polymer and to reduce agglomeration. 2g of uncoated nano-precipitated CaCO3 (NPCC) has been sonicated with an UP400S in 30ml ethanol. 9 wt% of stearic acid has been dissolved in ethanol. Ethanol with staeric acid was then mixed with the sonificated suspension.
Device Recommendation:
UP400S with 22mm diameter sonotrode (H22D), and flow cell with cooling jacket
Reference/ Research Paper:
Kow, K. W.; Abdullah, E. C.; Aziz, A. R. (2009): Effects of ultrasound in coating nano-precipitated CaCO3 with stearic acid. Asia‐Pacific Journal of Chemical Engineering 4/5, 2009. 807-813.

Cellulose nanocrystals

Ultrasonic application:
Cellulose nanocrystals (CNC) prepared from eucalyptus cellulose CNCs: Cellulose nano-crystals prepared from eucalyptus cellulose were modified by the reaction with methyl adipoyl chloride, CNCm, or with a mixture of acetic and sulfuric acid, CNCa. Therefore, freeze-dried CNCs, CNCm and CNCa were redispersed in pure solvents (EA, THF or DMF) at 0.1 wt%, by magnetic stirring overnight at 24 ± 1 degC, followed by 20 min. sonication using the probe-type ultrasonicator UP100H. Sonication was carried out with 130 W/cm2 intensity at 24 ± 1 degC. After that, CAB was added to the CNC dispersion, so that the final polymer concentration was 0.9 wt%.
Device Recommendation:
UP100H
Reference/ Research Paper:
Blachechen, L. S.; de Mesquita, J. P.; de Paula, E. L.; Pereira, F. V.; Petri, D. F. S. (2013): Interplay of colloidal stability of cellulose nanocrystals and their dispersibility in cellulose acetate butyrate matrix. Cellulose 20/3, 2013. 1329-1342.

Cerium nitrate doped silane

Ultrasonic application:
Cold-rolled carbon steel panels (6.5cm 6.5cm 0.3cm; chemically cleaned and mechanically polished) were used as metallic substrates. Prior to the coating application, the panels were ultrasonically cleaned with acetone then cleaned by an alkaline solution (0.3molL 1 NaOH solution) at 60°C for 10 min. For using as a primer, prior to substrate pretreatment, a typical formulation including 50 parts of γ-glycidoxypropyltrimethoxysilane (γ-GPS) was diluted with about 950 parts of methanol, in pH 4.5 (adjusted with acetic acid) and allowed for the hydrolysis of silane. Preparation procedure for doped silane with cerium nitrate pigments was the same, except that 1, 2, 3 wt% of cerium nitrate was added to the methanol solution prior to (γ-GPS) addition, then this solution was mixed with a propeller stirrer at 1600 rpm for 30 min. at room temperature. Then, the cerium nitrate containing dispersions were sonicated for 30 min at 40°C with an external cooling bath. The ultrasonication process was performed with the ultrasonicator UIP1000hd (1000W, 20 kHz) with an inlet ultrasound power of around 1 W/mL. Substrate pretreatment was carried out by rinsing each panel for 100 sec. with the appropriate silane solution. After treatment, the panels were allowed to dry at room temperature for 24 h, then the pretreated panels were coated with a two-pack amine-cured epoxy. (Epon 828, shell Co.) to make 90μm wet film thickness. Epoxy coated panels were allowed to cure for 1h at 115°C, after curing of epoxy coatings; the dry film thickness was about 60μm.
Device Recommendation:
UIP1000hd
Reference/ Research Paper:
Zaferani, S.H.; Peikari, M.; Zaarei, D.; Danaei, I. (2013): Electrochemical effects of silane pretreatments containing cerium nitrate on cathodic disbonding properties of epoxy coated steel. Journal of Adhesion Science and Technology 27/22, 2013. 2411–2420.

Clay: Dispersion/ Fractionation

Ultrasonic application:
Particle-size fractionation: To isolate < 1 μm particles from 1-2 μm particles, clay-size particles (< 2 μm) have been separated in an ultrasonic field and by the following application of different sedimentation speeds.
The clay-size particles (< 2 μm) were separated by ultrasonication with an energy input of 300 J mL-1 (1 min.) using probe type ultrasonic disintegrator UP200S (200W, 24kHz) equipped with 7 mm diameter sonotrode S7. After ultrasonic irradiation the sample was centrifuged at 110 x g (1000 rpm) for 3 min. The settling phase (fractionation rest) was next used in density fractionation for the isolation of the light density fractions, and obtained floating phase (< 2 μm fraction) was transferred to another centrifugation tube and centrifuged at 440 x g (2000 rpm) for 10 min. to separate < 1 μm fraction (supernatant) from 1-2 μm fraction (sediment). The supernatant containing < 1 μm fraction was transferred to the another centrifugation tube and after adding of 1 mL MgSO4 centrifuged at 1410 x g (4000 rpm) for 10 min to decant the rest of water.
To avoid overheating of the sample, the procedure was repeated 15 times.
Device Recommendation:
UP200S with S7 or UP200St with S26d7
Reference/ Research Paper:
Jakubowska, J. (2007): Effect of irrigation water type on soil organic matter (SOM) fractions and their interactions with hydrophobic compounds. Dissertation Martin-Luther University Halle-Wittenberg 2007.

Clay: Exfoliation of Inorganic Clay

Ultrasonic application:
Inorganic clay was exfoliated to prepare pullulan-based nano composites for the coating dispersion. Therefore, a fixed amount of pullulan (4 wt% wet basis) was dissolved in water at 25degC for 1 h under gentle stirring (500 rpm). At the same time, clay powder, in a quantity ranging from 0.2 and 3.0 wt%, was dispersed in water under vigorous stirring (1000 rpm) for 15 minutes. The resulting dispersion was ultrasonicated by means of an UP400S (powermax = 400 W; frequency = 24 kHz) ultrasonic device equipped with a titanium sonotrode H14, tip diameter 14 mm, amplitudemax = 125 μm; surface intensity = 105 Wcm-2) under the following conditions: 0.5 cycles and 50% amplitude. The duration of the ultrasonic treatment varied in accordance with the experimental design. The organic pullulan solution and the inorganic dispersion were then mixed together under gentle stirring (500 rpm) for additional 90 minutes. After mixing, the concentrations of the two components corresponded to an inorganic/organic (I/O) ratio ranging from 0.05 to 0.75. The size distribution in water dispersion of the Na+-MMT clays before and after ultrasonic treatment was assessed using an IKO-Sizer CC-1 nanoparticle analyzer.
For a fixed amount of clays the most effective sonication time was found to be 15 minutes, while longer ultrasound treatment increases the P’O2 value (due to reaggregation) which decreases again at the highest sonication time (45 min), presumably owing to the fragmentation of both platelets and tactoids.
According to the experimental setup adopted in Introzzi’s dissertation, an energy unit output of 725 Ws mL-1 was calculated for the 15-minute treatment while an extended ultrasonication time of 45 minutes yielded a unit energy consumption of 2060 Ws mL-1. This would allow the saving of quite a high amount of energy throughout the whole process, which will eventually be reflected in the final throughput costs.
Device Recommendation:
UP400S with sonotrode H14
Reference/ Research Paper:
Introzzi, L. (2012): Development of High Performance Biopolymer Coatings for Food Packaging Applications. Dissertation University of Milano 2012.

Conductive ink

Ultrasonic application:
The conductive ink was prepared by dispersing the Cu+C and Cu+CNT particles with dispersants in a mixed solvent (Publication IV). The dispersants were three high molecular weight dispersing agents, DISPERBYK-190, DISPERBYK-198, and DISPERBYK-2012, intended for water-based carbon black pigment disper- sions by BYK Chemie Gmbh. De-ionised water (DIW) was used as the main solvent. Ethylene glycol monomethyl ether (EGME) (Sigma-Aldrich), ethylene glycol monobuthyl ether (EGBE) (Merck), and n-propanol (Honeywell Riedel-de Haen) were used as co-solvents.
The mixed suspension was sonicated for 10 minutes in an ice bath using a UP400S ultrasonic processor. Thereafter, the suspension was left to settle for an hour, followed by decanting. Prior to spin coating or printing, the suspension was sonicated in an ultrasonic bath for 10 min.
Device Recommendation:
UP400S
Reference/ Research Paper:
Forsman, J. (2013): Production of Co, Ni, and Cu nanoparticles by hydrogen reduction. Dissertation VTT Finland 2013.

Copper phathlocyanine

Ultrasonic application:
Decomposition of metallophthalocyanines
Copper phathlocyanine (CuPc) is sonicated with water and organic solvents at ambient temperature and atmospheric pressure in the presence of an oxidant as catalyst using the 500W ultrasonicator UIP500hd with flow-through chamber. Sonication intensity: 37–59 W/cm2, sample mixture: 5 mL of sample (100 mg/L), 50 D/D water with choloform and pyridine at 60% of ultrasonic amplitude. Reaction temperature: 20°C at atmospheric pressure.
Destruction rate of up to 95% within 50 min. of sonication.
Device Recommendation:
UIP500hd

Dibutyrylchitin (DBCH)

Ultrasonic application:
Long polymeric macro-molecules can be broken by ultrasonication. Ultrasonically assisted molar mass reduction allows to avoid undesired side reactions or the separation of by-products. It is believed, that ultrasonic degradation, unlike chemical or thermal decomposition, is a non-random process, with cleavage taking place roughly at the center of the molecule. For this reason larger macromolecules degrade faster.
Experiments were performed by using ultrasound generator UP200S equipped with sonotrode S2. Ultrasonic setting was at 150 W power input. Solutions of dibutyrylchitin in dimethylacetamide, at concentration of the former of 0.3 g/100 cm3 having a volume of 25 cm3 were used. The sonotrode (ultrasonic probe/ horn) was immersed in polymer solution 30 mm below the surface level. The solution was placed in thermostated water bath maintained at 25°C. Each solution was irradiated for predetermined time interval. After this time the solution was diluted 3 times and subjected to size exclusion chromatography analysis.
The presented results indicate that dibutyrylchitin does not undergo destruction by power ultrasound, but there is a degradation of the polymer, which is understood as a controlled sonochemical reaction. Therefore, ultrasound may be used for reduction of average molar mass of dibutyrylchitin and the same applies to the ratio of weight average to number average molar mass. The observed changes are intensified by increasing ultrasound power and sonification duration. There was also significant effect of the starting molar mass upon extent of DBCH degradation under studied condition of sonification: the higher the initial molar mass the greater the degree of degradation.
Device Recommendation:
UP200S
Reference/ Research Paper:
Szumilewicz, J.; Pabin-Szafko, B. (2006): Ultrasonic Degradation of Dibuyrylchitin. Polish Chitin Society, Monograph XI, 2006. 123-128.

Ferrocine powder

Ultrasonic application:
A sonochemical route to prepare SWNCNTs: Silica powder (diameter 2–5 mm) is added to a solution of 0.01 mol% ferrocene in p-xylene followed by sonication with an UP200S equipped with titanium tip probe (sonotrode S14). Ultrasonication was carried out for 20 min. at room temperature and atmospheric pressure. By the ultrasonically assisted synthesis, high-purity SWCNTs were produced on the surface of silica powder.
Device Recommendation:
UP200S with ultrasonic probe S14
Reference/ Research Paper:
Srinivasan C.(2005): A SOUND method for synthesis of single-walled carbon nanotubes under ambient conditions. Current Science 88/ 1, 2005. 12-13.

Fly ash/ metakaolinite

Ultrasonic application:
Leaching test: 100mL of leaching solution was added to 50g of the solid sample. Sonication intensity: max. 85 W/cm2 with UP200S in a water bath of 20°C.
Geopolymerization: The slurry was mixed with an UP200S ultrasonic homogenizer for geopolymerization. Sonication intensity was max. 85 W/cm2. For cooling, sonication was carried out in an ice water bath.
The application of power ultrasound for geopolymerisation results in increasing compressive strength of the formed geopolymers and increasing strength with increased sonication up to a certain time. The dissolution of metakaolinite and fly ash in alkaline solutions was enhanced by ultrasonication as more Al and Si was released into the gel phase for polycondensation.
Device Recommendation:
UP200S
Reference/ Research Paper:
Feng, D.; Tan, H.; van Deventer, J. S. J. (2004): Ultrasound enhanced geopolymerisation. Journal of Materials Science 39/2, 2004. 571-580

Graphene

Ultrasonic application:
Pure graphene sheets can be produced in large quantities as shown by the work of Stengl et al. (2011) during the production of non-stoichiometric TiO2 graphene nano composite by thermal hydrolysis of suspension with graphene nanosheets and titania peroxo complex. The pure graphene nanosheets were produced from natural graphite under power ultrasonication with a 1000W ultrasonic processor UIP1000hd in a high-pressure ultrasound reactor chamber at 5 barg. The graphene sheets obtained are characterized by a high specific surface area and unique electronic properties. The researchers claim that the quality of the ultrasonically prepared graphene is much higher than graphene obtained by Hummer’s method, where graphite is exfoliated and oxidized. As the physical conditions in the ultrasonic reactor can be precisely controlled and by the assumption that the concentration of graphene as a dopant will vary in the range of 1 – 0.001%, the production of graphene in a continuous system on commercial scale is possible.
Device Recommendation:
UIP1000hd
Reference/ Research Paper:
Stengl, V.; Popelková, D.; Vlácil, P. (2011): TiO2-Graphene Nanocomposite as High Performance Photocatalysts. In: Journal of Physical Chemistry C 115/2011. pp. 25209-25218.
Click here to read more about the ultrasonic production and preparation of graphene!

Graphene Oxide

Ultrasonic application:
Graphene oxide (GO) layers have been prepared at the following route: 25mg of graphene oxide powder were added in 200 ml of de-ionized water. By stirring they obtained an inhomogeneous brown suspension. The resulting suspensions were sonicated (30 min, 1.3 × 105J), and after drying (at 373 K) the ultrasonically treated graphene oxide was produced. A FTIR spectroscopy showed that the ultrasonic treatment did not change the functional groups of graphene oxide.
Device Recommendation:
UP400S
Reference/ Research Paper:
Oh, W. Ch.; Chen, M. L.; Zhang, K.; Zhang, F. J.; Jang, W. K. (2010): The Effect of Thermal and Ultrasonic Treatment on the Formation of Graphene-oxide Nanosheets. Journal of the Korean Physical Society 4/56, 2010. pp. 1097-1102.
Click here to read more about the ultrasonic graphene exfoliation and preparation!

Hairy polymer nanoparticles by degradation of Poly(vinyl alcohol)

Ultrasonic application:
A simple one-step procedure, based on the sonochemical degradation of water-soluble polymers in aqueous solution in the presence of a hydrophobic monomer leads to functional hairy polymer particles in a residual-free serum. All polymerizations were performed in a 250 mL double-walled glass reactor, equipped with baffles, a temperature sensor, magnetic stirrer bar and a Hielscher US200S ultrasonic processor (200 W, 24 kHz) equipped with a S14 titanium sonotrode (diameter = 14 mm, length = 100 mm).
A poly(vinyl alcohol) (PVOH) solution was prepared by dissolving an accurate amount of PVOH in water, overnight at 50°C under vigorous stirring. Prior to the polymerization, the PVOH solution was placed inside the reactor and the temperature adjusted to the desired reaction temperature. The PVOH solution and the monomer were purged separately for 1 hour with argon. The required amount of monomer was added drop wise to the PVOH solution under vigorous stirring. Subsequently, the argon purge was removed from the liquid and the ultrasonication with the UP200S was started at an amplitude of 80%. It should be noted here that the use of argon serves two purposes: (1) the removal of oxygen and (2) it is required for creating ultrasonic cavitations. Hence a continuous argon flow would in principle be beneficial for the polymerization, but excessive foaming occurred; the procedure that we followed here avoided this problem and was sufficient for an efficient polymerization. Samples were withdrawn periodically to monitor conversion by gravimetry, molecular weight distributions and/or particle size distributions.
Device Recommendation:
US200S
Reference/ Research Paper:
Smeets, N. M. B.; E-Rramdani, M.; Van Hal, R. C. F.; Gomes Santana, S.; Quéléver, K.; Meuldijk, J.; Van Herk, JA. M.; Heuts, J. P. A. (2010): A simple one-step sonochemical route towards functional hairy polymer nanoparticles. Soft Matter, 6, 2010. 2392-2395.

HiPco-SWCNTs

Ultrasonic application:
Dispersion of HiPco-SWCNTs with UP400S: In a 5 mL vial 0.5 mg oxidized HiPcoTM SWCNTs (0.04 mmol carbon) were suspended in 2 mL of deionized water by an ultrasound processor UP400S to yield a black-colored suspension (0.25 mg/mL SWCNTs). To this suspension, 1.4 μL of a PDDA solution (20 wt./%, molecular weight = 100,000-200,000) were added and the mixture was vortex-mixed for 2 minutes. After an additional sonication in an water bath of 5 minutes, the nanotube suspension was centrifuged at 5000g for 10 minutes. The supernatant was taken for AFM measurements and subsequently functionalized with siRNA.
Device Recommendation:
UP400S
Reference/ Research Paper:
Jung, A. (2007): Functional Materials based on Carbon Nanotubes. Dissertation Friedrich-Alexander-Universität Erlangen-Nürnberg 2007.

Hydroxyapatite bio-ceramic

Ultrasonic application:
For the synthesis of nano-HAP, a 40 mL solution of 0.32M Ca(NO3)2 ⋅ 4H2O was placed into a small beaker. The solution pH was then adjusted to 9.0 with approximately 2.5 mL ammonium hydroxide. The solution was then sonicated with the ultrasound processor UP50H (50 W, 30 kHz) equipped with sonotrode MS7 (7mm horn diameter) set at maximum amplitude of 100% for 1 hour. At the end of the first hour a 60 mL solution of 0.19M [KH2PO4] was then slowly added drop-wise into the first solution while undergoing a second hour of ultrasonic irradiation. During the mixing process, the pH value was checked and maintained at 9 while the Ca/P ratio was maintained at 1.67. The solution was then filtered using centrifugation (~2000 g), after which the resultant white precipitate was proportioned into a number of samples for heat treatment. There were two sample sets made, the first consisting of twelve samples for thermal treatment in tube furnace and the second consisting of five samples for microwave treatment
Device Recommendation:
UP50H
Reference/ Research Paper:
Poinern, G. J. E.; Brundavanam, R.; Thi Le, X.; Djordjevic, S.; Prokic, M.; Fawcett, D.(2011): Thermal and ultrasonic influence in the formation of nanometer scale hydroxyapatite bio-ceramic. International Journal of Nanomedicine 6, 2011. 2083-2095.

Inorganic fullerene-like WS2 nanoparticles

Ultrasonic application:
Ultrasonication during electrodeposition of inorganic fullerene (IF)-like WS2 nanoparticles in a nickel matrix leads to a more uniform and compact coating is achieved. Moreover, the application of ultrasound has a significant effect on the weight percentage of the particles incorporated in the metal deposit. Thus, the wt.% of IF-WS2 particles in the nickel matrix increases from 4.5 wt.% (in films grown under mechanical agitation only) to about 7 wt.% (in films prepared under sonication at 30 W cm-2 of ultrasound intensity).
Ni/IF-WS2 nanocomposite coatings were electrolytically deposited from a standard nickel Watts bath to which industrial grade IF-WS2 (inorganic fullerenes-WS2) nanoparticles were added.
For the experiment, IF-WS2 was added to the nickel Watts electrolytes and the suspensions were intensively stirred using a magnetic stirrer (300 rpm) for at least 24 h at room temperature prior to the codeposition experiments. Immediately before the electrodeposition process, the suspensions were submitted to a 10 min. ultrasonic pretreatment to avoid agglomeration. For ultrasonic irradiation, an UP200S probe-type ultrasonicator with a sonotrode S14 (14 mm tip diameter) was adjusted at 55% amplitude.
Cylindrical glass cells with volumes of 200 mL were used for the codeposition experiments. Coatings were deposited on flat commercial mild steel (grade St37) cathodes of 3cm2. The anode was a pure nickel foil (3cm2) positioned on the side of the vessel, face to face to the cathode. The distance between anode and cathode was 4cm. The substrates were degreased, rinsed in cold distilled water, activated in a 15% HCl solution (1 min.) and rinsed in distilled water again. Electrocodeposition was carried out at a constant current density of 5.0 A dm-2 during 1 h using a DC power supply (5 A/30 V, BLAUSONIC FA-350). In order to maintain a uniform particle concentration in the bulk solution, two agitation methods were used during the electrodeposition process: mechanical agitation by a magnetic stirrer (ω = 300 rpm) located at the bottom of the cell, and ultrasonication with the probe-type ultrasonic device UP200S. The ultrasonic probe (sonotrode) was directly immersed into the solution from above and accurately positioned between the working and counter electrodes in a way that there was no shielding. The intensity of the ultrasound directed to the electrochemical system was varied by controlling the ultrasound amplitude. In this study, vibration amplitude was adjusted to 25, 55 and 75% in a continuous mode, corresponding to an ultrasonic intensity of 20, 30 and 40 W cm-2 respectively, measured by a processor connected to an ultrasonic power meter (Hielscher Ultrasonics). The electrolyte temperature was maintained at 55◦C using a thermostat. Temperature was measured before and after each experiment. Temperature increase due to ultrasonic energy did not exceed 2–4◦C. After electrolysis, the samples were ultrasonically cleaned in ethanol for 1 min. to remove loosely adsorbed particles from the surface.
Device Recommendation:
UP200S with ultrasonic horn / sonotrode S14
Reference/ Research Paper:
García-Lecina, E.; García-Urrutia, I.; Díeza, J.A.; Fornell, B.; Pellicer, E.; Sort, J. (2013): Codeposition of inorganic fullerene-like WS2 nanoparticles in an electrodeposited nickel matrix under the influence of ultrasonic agitation. Electrochimica Acta 114, 2013. 859-867.

Latex Synthesis

Ultrasonic application:
Preparation of P(St-BA) latex
P(St-BA) poly(styrene-r-butyl acrylate) P(St-BA) latex particles were synthesized by emulsion polymerization in the presence of surfactant DBSA. 1 g of DBSA was first dissolved in 100 mL of water in a three-necked flask and the pH value of the solution was adjusted to 2.0. Mixed monomers of 2.80 g St and 8.40 g BA with the initiator AIBN (0.168 g) were poured into the DBSA solution. The O/W emulsion was prepared via magnetic stirring for 1 h followed by sonication with an UIP1000hd equipped with ultrasonic horn (probe/ sonotrode) for another 30 min in the ice bath. Finally, the polymerization was carried out at 90degC in an oil bath for 2 h under a nitrogen atmosphere.
Device Recommendation:
UIP1000hd
Reference/ Research Paper:
Fabrication of flexible conductive films derived from poly(3,4-ethylenedioxythiophene)epoly(styrenesulfonic acid) (PEDOT:PSS) on the nonwoven fabrics substrate. Materials Chemistry and Physics 143, 2013. 143-148.
Click here to read more about the sono-synthesis of latex!

Lead Removal (Sono-Leaching)

Ultrasonic application:
Ultrasonic leaching of Lead from contaminated soil:
The ultrasound leaching experiments were performed with an ultrasonic device UP400S with a titanium sonic probe (diameter 14mm), which operates at a frequency of 20kHz. The ultrasonic probe (sonotrode) was calorimetrically calibrated with the ultrasonic intensity set to 51 ± 0.4 W cm-2 for all the sono-leaching experiments. The sono-leaching experiments were thermostated using a flat bottom jacketed glass cell at 25 ± 1°C. Three systems were employed as soil leaching solutions (0.1L) under sonication: 6 mL of 0.3 mol L-2 of acetic acid solution (pH 3.24), 3% (v/v) nitric acid solution (pH 0.17) and a buffer of acetic acid/acetate (pH 4.79) prepared by mixing 60mL 0f 0.3 mol L-1 acetic acid with 19 mL 0.5 mol L-1 NaOH. After the sono-leaching process, samples were filtered with filter paper to separate the leachate solution from soil followed by lead electrodeposition of the leachate solution and digestion of soil after the application of ultrasound.
Ultrasound has been proven to be a valuable tool in enhancing the leachate of lead from pollute soil. Ultrasound is also an effective method for the near total removal of leachable lead from soil resulting in a much less hazardous soil.
Device Recommendation:
UP400S with sonotrode H14
Reference/ Research Paper:
Sandoval-González, A.; Silva-Martínez, S.; Blass-Amador, G. (2007): Ultrasound Leaching and Electrochemical Treatment Combined for Lead Removal Soil. Journal of New Materials for Electrochemical Systems 10, 2007. 195-199.

Nanoparticle Suspension Preparation

Ultrasonic application:
Bare nTiO2 (5nm by transmission electron microscopy (TEM)) and nZnO (20nm by TEM) and polymer-coated nTiO2 (3-4nm by TEM) and nZnO (3-9nm by TEM) powders were used to prepare the nanoparticle suspensions. The crystalline form of the NPs was anatase for the nTiO2 and amorphous for nZnO.
0.1 g of nanoparticle powder was weighed into a 250mL beaker containing a few drops of deionized (DI) water. The nanoparticles were then mixed with a stainless steel spatula, and the beaker filled to 200 mL with DI water, stirred, and then ultrasonicated for 60 sec. at 90% amplitude with Hielscher’s UP200S ultrasonic processor, yielding a 0.5 g/L stock suspension. All stock suspensions were kept for a maximum of two days at 4°C.
Device Recommendation:
UP200S or UP200St
Reference/ Research Paper:
Petosa, A. R. (2013): Transport, deposition and aggregation of metal oxide nanoparticles in saturated granular porous media: role of water chemistry, collector surface and particle coating. Dissertation McGill University Montreal, Quebec, Canada 2013. 111-153.
Click here to learn more about ultrasonic dispersion of nano particles!

Magnetite nano particle precipitation

Ultrasonic application:
The magnetite (Fe3O4) nanoparticles are produced by co-precipitation of an aqueous solution of iron(III)chloride hexahydrate and iron(II)sulfate heptahydrate with a molar ratio of Fe3+/Fe2+ = 2:1. The iron solution is precipitated with concentrated ammonium hydroxide and sodium hydroxide respectively. Precipitation reaction is carried out under ultrasonic irradiation, feeding the reactants through the caviatational zone in the ultrasonic flow-through reactor chamber. In order to avoid any pH gradient, the precipitant has to be pumped in excess. The particle size distribution of magnetite has been measured using photon correlation spectroscopy.The ultrasound induced mixing decreases the mean particle size from 12- 14 nm down to about 5-6 nm.
Device Recommendation:
UIP1000hd with flow cell reactor
Reference/ Research Paper:
Banert, T.; Horst, C.; Kunz, U., Peuker, U. A. (2004): Kontinuierliche Fällung im Ultraschalldurchflußreaktor am Beispiel von Eisen-(II,III) Oxid. ICVT, TU-Clausthal. Poster presented at GVC Annual Meeting 2004.
Banert, T.; Brenner, G.; Peuker, U. A. (2006): Operating parameters of a continuous sono-chemical precipitation reactor. Proc. 5. WCPT, Orlando Fl., 23.-27. April 2006.
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Nickel powders

Ultrasonic application:
Preparation of a suspension of Ni powders with a polyelectrolyte at basic pH (to prevent dissolution and to promote the development of NiO-enriched species at surface), acrylic-based polyelectrolyte and tetramethylammonium hydroxide (TMAH).
Device Recommendation:
UP200S
Reference/ Research Paper:
Mora, M.; Lennikov, V.; Amaveda, H.; Angurel, L. A.; de la Fuente, G. F.; Bona, M. T.; Mayoral, C.; Andres, J. M.; Sanchez-Herencia, J. (2009): Fabrication of Superconducting Coatings on Structural Ceramic Tiles. Applied Superconductivity 19/ 3, 2009. 3041-3044.

PbS - Lead Sulfide nanoparticle synthesis

Ultrasonic application:
At room temperature, 0.151 g lead acetate (Pb(CH3COO)2.3H2O) and 0.03 g of TAA (CH3CSNH2) were added to 5mL of the ionic liquid, [EMIM] [EtSO4], and 15mL of double distilled water in a 50mL beaker imposed to ultrasonic irradiation with an UP200S for 7 min. The tip of the ultrasonic probe/ sonotrode S1 was immersed directly in the reaction solution. The formed dark brown color suspension was centrifuged to get the precipitate out and washed two times with double distilled water and ethanol respectively to remove the unreacted reagents. To investigate the effect of ultrasound on the properties of the products, one more comparative sample was prepared, keeping the reaction parameters constant except that the product is prepared at continuous stirring for 24 h without the aid of ultrasonic irradiation.
Ultrasonic-assisted synthesis in aqueous ionic liquid at room temperature was proposed for preparation of PbS nanoparticles. This room-temperature and environmentally benign green method is fast and template-free, which shortens synthesis time remarkably and avoids the complicated synthetic procedures. The as-prepared nanoclusters show an enormous blue shift of 3.86 eV that can be attributed to very small size of particles and quantum confinement effect.
Device Recommendation:
UP200S
Reference/ Research Paper:
Behboudnia, M.; Habibi-Yangjeh, A.; Jafari-Tarzanag, Y.; Khodayari, A. (2008): Facile and Room Temperature Preparation and Characterization of PbS Nanoparticles in Aqueous [EMIM][EtSO4] Ionic Liquid Using Ultrasonic Irradiation. Bulletin of Korean Chemical Society 29/ 1, 2008. 53-56.

Purified Nanotubes

Ultrasonic application:
The purified nanotubes were then suspended in 1,2-dichloroethane (DCE) by sonication with a high-power ultrasound device UP400S, 400W, 24 kHz) at pulsed mode (cycles) to yield a black colored suspension. Bundles of agglomerated nanotubes were subsequently removed in a centrifugation step for 5 minutes at 5000 rpm.
Device Recommendation:
UP400S
Reference/ Research Paper:
Witte, P. (2008): Amphiphilic Fullerenes For Biomedical And Optoelectronical Applications. Dissertation Friedrich-Alexander-Universität Erlangen-Nürnberg 2008.

SAN/CNTs composite

Ultrasonic application:
To disperse CNTs in the SAN matrix, a Hielscher UIS250V with sonotrode for probe-type sonication was used. First CNTs were dispersed in 50mL of distilled water by sonication for about 30 min. To stabilize the solution, SDS was added at the ratio of ~1% of the solution. After that the obtained aqueous dispersion of CNTs was combined with the polymer suspension and mixed for 30 min. with Heidolph RZR 2051 mechanical agitator, and then repeatedly sonicated for 30 min. For analysis, SAN dispersions containing different concentrations of CNTs were cast in Teflon forms and dried at ambient temperature for 3–4 days.
Device Recommendation:
UIS250v
Reference/ Research Paper:
Bitenieks, J.; Meri, R. M.; Zicans, J.; Maksimovs, R.; Vasile, C.; Musteata, V. E. (2012): Styrene–acrylate/carbon nanotube nanocomposites: mechanical, thermal, and electrical properties. In: Proceedings of the Estonian Academy of Sciences 61/ 3, 2012. 172–177.

Silicon Carbide (SiC) nanopowder

Ultrasonic application:
Silicon carbide (SiC) nanopowder was deagglomerated and distributed in tetra- hydrofurane solution of the paint using a Hielscher UP200S high power ultrasonic processor, operating at an acoustic power density of 80 W/cm2. SiC deagglomeration was initially carried out in pure solvent with some detergent, then portions of the paint were subsequently added. The whole process took 30 minutes and 60 minutes in the case of samples prepared for dip coating and silk screen printing, respectively. Adequate cooling of the mixture was provided during ultrasonification to avoid solvent boiling. After ultrasonication, tetrahydrofurane was evaporated in a rotary evaporator and the hardener was added to the mixture to obtain an appropriate viscosity for printing. The SiC concentration in the resulting composite was 3% wt in samples prepared for dip coating. For silk screen printing, two batches of samples were prepared, with an SiC content of 1 – 3% wt for preliminary wear and friction tests and 1.6 – 2.4% wt for fine tuning the composites on the basis of wear and friction tests results.
Device Recommendation:
UP200S
Reference/ Research Paper:
Celichowski G.; Psarski M.; Wiśniewski M. (2009): Elastic Yarn Tensioner with a Noncontinuous Antiwear Nanocomposite Pattern. Fibres & Textiles in Eastern Europe 17/ 1, 2009. 91-96.

SWNT Single-Walled Carbon Nanotubes

Ultrasonic application:
Sonochemical synthesis: 10 mg SWNT and 30ml 2%MCB solution 10 mg SWNT and 30ml 2%MCB solution, UP400S Sonication intensity: 300 W/cm2, sonication duration: 5h
Device Recommendation:
UP400S
Reference/ Research Paper:
Koshio, A.; Yudasaka, M.; Zhang, M.; Iijima, S. (2001): A Simple Way to Chemically React Single-Wall Carbon Nanotubes with Organic Materials Using Ultrasonication. Nano Letters 1/ 7, 2001. 361–363.

Thiolated SWCNTs

Ultrasonic application:
25 mg of thiolated SWCNTs (2.1 mmol carbon) were suspended in 50 mL of deionized water using an 400W ultrasound processor (UP400S). Subsequently the suspension was given to the freshly prepared Au(NP) solution and the mixture was stirred for 1h. Au(NP)-SWCNTs were extracted by microfiltration (cellulose nitrate) and washed thoroughly with deionized water. The filtrate was red-colored, as the small Au(NP) (average diameter ≈ 13 nm) could effectively pass the filter membrane (pore size 0.2μm).
Device Recommendation:
UP400S
Reference/ Research Paper:
Jung, A. (2007): Functional Materials based on Carbon Nanotubes. Dissertation Friedrich-Alexander-Universität Erlangen-Nürnberg 2007.

TiO2/ Perlite composite

Ultrasonic application:
The TiO2 /perlite composite materials were preparedlows. Initially, 5 mL titanium isopropoxide (TIPO), Aldrich 97%, was dissolved in 40 mL ethanol, Carlo Erba, and stirred for 30 min. Then, 5 g perlite was added and the dispersion was stirred for 60 min. The mixture was further homogenized using the ultrasound tip sonicator UIP1000hd. Total energy input of 1 Wh was applied for sonication time for 2 min. Finally, the slurry was diluted with ethanol to receive 100 mL suspension and the liquid obtained was nominated as precursor solution (PS). The prepared PS was ready to be processed through the flame spray pyrolysis system.
Device Recommendation:
UIP1000hd
Reference/ Research Paper:
Giannouri, M.; Kalampaliki, Th.; Todorova, N.; Giannakopoulou,T.; Boukos, N.; Petrakis, D.; Vaimakis, T.; Trapalis, C. (2013): One-Step Synthesis of TiO2/Perlite Composites by Flame Spray Pyrolysis and Their Photocatalytic Behavior. International Journal of Photoenergy 2013.
Ultrasonic homogenizers are powerful mixing tools to disperse, deagglomerate and mill particles to submicron- and nano-size

Ultrasonic Disperser UP200S for Particle and Powder Processing

Ultrasonic Particle Processes:

Dispersing

Deagglomeration

Milling

Precipitation

Synthesis

Functionalization

Polymerization

    – Leaching
    – Coating
    – Crystallization

Sono-Fragmentation

Ultrasonic Sol-Gel Routes

Sono-Catalysis

Dissolving

Ultrasonic Scavenging


Ultrasonic devices for bench-top and production such as the UIP1500hd provide full industrial grade. (Click to enlarge!)

Ultrasonic device UIP1500hd with flow-through reactor

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Powerful ultrasound coupled into liquids generates intense cavitation. The extreme cavitational effects create fine-powder slurries with particles sizes in the submicron- and nano-range. Furthermore, the particle surface area is activated. Microjet and shockwave impact and interparticle collisions have substantial effects on the chemical composition and physical morphology of solids that can dramatically enhance chemical reactivity of both organic polymers and inorganic solids.

“The extreme conditions inside collapsing bubbles produce highly reactive species that can be used for various purposes, for instance, the initiation of polymerization without added initiators. As another example, the sonochemical decomposition of volatile organometallic precursors in high-boiling-point solvents produces nanostructured materials in various forms with high catalytic activities. Nanostructured metals, alloys, carbides and sulfides, nanometer colloids, and nanostructured supported catalysts can all be prepared by this general route.”

[Suslick/ Price 1999: 323]

Literature/References

  • Suslick, K. S.; Price, G. J. (1999): Applications of ultrasound to Materials Chemistry. Annu. Rev. Mater. Sci. 29, 1999. 295-326.

Facts Worth Knowing

Ultrasonic tissue homogenizers are often referred to as probe sonicator, sonic lyser, sonolyzer, ultrasound disruptor, ultrasonic grinder, sono-ruptor, sonifier, sonic dismembrator, cell disrupter, ultrasonic disperser or dissolver. The different terms result from the various applications that can be fulfilled by sonication.