Improved optical limiting performance of laser-ablation-generated metal nanoparticles due to silica-microsphere-induced local field enhancement

• Zheren Du,
• Lianwei Chen,
• Tsung-Sheng Kao,
• Mengxue Wu and
• Minghui Hong

Beilstein J. Nanotechnol. 2015, 6, 1199–1204, doi:10.3762/bjnano.6.122

• ]. Figure 1b shows a photograph of the laser-generated gold and silver nanoparticle dispersions fabricated by the LAL technique. Droplets of the nanoparticle colloidal solution were placed on a polished silicon substrate. These droplets were dried and the nanoparticles on the silicon substrate were

Structure and mechanism of the formation of core–shell nanoparticles obtained through a one-step gas-phase synthesis by electron beam evaporation

• Andrey V. Nomoev,
• Sergey P. Bardakhanov,
• Makoto Schreiber,
• Dashima G. Bazarova,
• Nikolai A. Romanov,
• Boris B. Baldanov,
• Bair R. Radnaev and
• Viacheslav V. Syzrantsev

Beilstein J. Nanotechnol. 2015, 6, 874–880, doi:10.3762/bjnano.6.89

• than that of Cu (Tb(Si) = 3538 K, Tb(Cu) = 2835 K) as is the surface tension. It is reasonable to assume that as the mixed vapour cools, droplets of Cu and Si condense from the gas phase and come into contact. In the aggregated droplets, the silicon atoms will segregate to the surface of the droplet

• form the shell; the amorphous nature resulting from the SiO2. This solid shell around the liquid copper allows the Cu to crystallize undisturbed from the outer atmosphere; forming multiple contact twinned structure instead of polycrystals. Excess Si and Cu which did not form into mixed droplets may

• later agglomerate onto the shell surface; the adsorbed copper oxidizing when the powder is exposed to air. Particles with moiré patterns may form when insufficient Si droplets mix with Cu; leaving uncovered areas on the copper that could be oxidized. The variations in the particle sizes of the Cu@silica

Capillary and van der Waals interactions on CaF₂ crystals from amplitude modulation AFM force reconstruction profiles under ambient conditions

• Annalisa Calò,
• Oriol Vidal Robles,
• Sergio Santos and
• Albert Verdaguer

Beilstein J. Nanotechnol. 2015, 6, 809–819, doi:10.3762/bjnano.6.84

• reconstructed force curve of Figure 2a a step-like discontinuity that could be associated with the formation of a capillary bridge is not distinguishable. Instead, a slow decay is observed in the force at a distance, 2.33 nm, that approximately matches the sum of the height of the absorbed water droplets on top

• nanoparticle and a flat plate [47]. Finally notice that, due to the imaging conditions (see Experimental section), the apparent height of the water droplets/layers measured by AFM topography (Figure 1a and Figure 1b) should be equal or close to the true value as water perturbation due to mechanical contact is

• ) Experimental normalized Fts, Ediss and ΔΦ curves vs dmin collected on a CaF2 sample containing water droplets (a) and on a water patch on top of the CaF2 crystal (c). FAD = 2.8 nN, Emax = 82 eV, ΔΦmax = 11.0° in (a) and FAD = 2.0 nN, Emax = 114 eV, ΔΦmax = 13.9° in (c) (see main text). A0 in (a) and (c) is 23

Applications of three-dimensional carbon nanotube networks

• Manuela Scarselli,
• Paola Castrucci,
• Francesco De Nicola,
• Ilaria Cacciotti,
• Francesca Nanni,
• Emanuela Gatto,
• Mariano Venanzi and
• Maurizio De Crescenzi

Beilstein J. Nanotechnol. 2015, 6, 792–798, doi:10.3762/bjnano.6.82

• hydrophobicity one can measure the advanced static contact angle at room temperature for water droplets of different volumes ranging from 5 to 20 µL, as shown in Figure 4a. The presence of a composite solid–liquid–air interface explains the high value of the measured contact angle (Θ = 175°), as evaluated in

• junctions between CNTs. Electron energy loss spectra (Ep = 300 eV) obtained on the CNT-sponge. The π and π + σ plasmons have been emphasized for better view (red line). Photographs of water droplets of different volumes (a) and contact angle profile of a single drop (b) on the bulk material. Stability of

Hematopoietic and mesenchymal stem cells: polymeric nanoparticle uptake and lineage differentiation

• Ivonne Brüstle,
• Thomas Simmet,
• Gerd Ulrich Nienhaus,
• Katharina Landfester and
• Volker Mailänder

Beilstein J. Nanotechnol. 2015, 6, 383–395, doi:10.3762/bjnano.6.38

• chondrogenic differentiation, the alkaline phosphatase activity for the osteogenic differentiation, as well as the lipid droplets for the adipogenic differentiation showed the same characteristics as the sample without nanoparticles. To investigate if the presence of polymeric nanoparticles can induce

• was performed. In the case of adipogenic differentiation, lipid droplets could be visualized with Oil-red O, the extracellular matrix developing during chondrogensis could be detected with methylene blue staining and, in the case of osteogenic differentiation, the activity of alkaline phosphatase was

• was detected by staining with Loeffler´s methylene blue (Carl Roth, Karlsruhe, Germany). Adipogenic differentiation was detected by the lipophilic dye Oil Red O (Sigma Aldrich), which stained the lipid droplets of adipocytes deep red. Hematoxylin–Harris was used for counter staining which stained the

Exploiting the hierarchical morphology of single-walled and multi-walled carbon nanotube films for highly hydrophobic coatings

• Francesco De Nicola,
• Paola Castrucci,
• Manuela Scarselli,
• Francesca Nanni,
• Ilaria Cacciotti and
• Maurizio De Crescenzi

Beilstein J. Nanotechnol. 2015, 6, 353–360, doi:10.3762/bjnano.6.34

• SWCNT films. Moreover, in Figure 3a and Figure 3b, images of water droplets cast on our SWCNT and MWCNT films are shown, with average contact angle values of θ = 110 ± 3° and θ = 97 ± 8°, respectively. These results can be ascribed to the particular morphology of both the films induced by the inherent

• the contact angle is due to the highly rough and porous surface of our samples. In addition, no roll-off angle value could be measured, evidently due to the high contact angle hysteresis, which pinned the droplets to the surface [2]. In order to better understand the origin of the enhancement provided

• carbon nanotube. Indeed, on our carbon nanotube films no contact angle (θ ≈ 0) can be measured for pure ethanol droplets. Therefore, we investigated all the wetting phenomena occurring on our carbon nanotube surface, exploring all the wetting states. We further noted that for θ ≈ 56°, (cos θ ≈ 0.56

Release behaviour and toxicity evaluation of levodopa from carboxylated single-walled carbon nanotubes

• Julia M. Tan,
• Jhi Biau Foo,
• Sharida Fakurazi and
• Mohd Zobir Hussein

Beilstein J. Nanotechnol. 2015, 6, 243–253, doi:10.3762/bjnano.6.23

• slides and detailed scans were performed in the 100–2000 cm−1 range. The nanotube product was first ultrasonicated in ethanol using a PowerSonic 420 (Hwashin Technology Co., Korea) device. Several droplets of the nanotube suspension were deposited onto a glass slide and then air dried at room temperature

Mechanical properties of MDCK II cells exposed to gold nanorods

• Anna Pietuch,
• Bastian Rouven Brückner,
• David Schneider,
• Marco Tarantola,
• Christina Rosman,
• Carsten Sönnichsen and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 223–231, doi:10.3762/bjnano.6.21

• /m. Considering these extremely stiff cells at high CTAB coated gold nanorods concentrations as liquid droplets is probably no longer justified. It is difficult to explain these extraordinary high values in terms of cortical or even membrane tension and inextensibility of the plasma membrane alone

Materials and characterization techniques for high-temperature polymer electrolyte membrane fuel cells

• Roswitha Zeis

Beilstein J. Nanotechnol. 2015, 6, 68–83, doi:10.3762/bjnano.6.8

• type of fuel cell is perfluorinated sulfonic acid (PFSA) polymer, which functions only in a highly hydrated state. On the other hand, water droplets which are building up underneath the gas diffusion layer (GDL) and the flow channels can partially block the gas supply of the cell. Therefore balancing

• regions represent PTFE agglomerates and gas pores with much lower conductivities. The average surface conductivity of the sprayed electrode is higher than that of the coated one. The PTFE distribution within the electrode is sensitive to its preparation technique. During spraying the small droplets of the

Formation of stable Si–O–C submonolayers on hydrogen-terminated silicon(111) under low-temperature conditions

• Yit Lung Khung,
• Siti Hawa Ngalim,
• Andrea Scaccabarozzi and
• Dario Narducci

Beilstein J. Nanotechnol. 2015, 6, 19–26, doi:10.3762/bjnano.6.3

• take up to 50 images per second. For each sessile droplet measurement three separate 5 μL droplets were dispensed onto the selected sample and the drop images were recorded. All drop images were then processed by an image analyzer that calculated both the left and right contact angles from the droplet

Poly(styrene)/oligo(fluorene)-intercalated fluoromica hybrids: synthesis, characterization and self-assembly

• Giuseppe Leone,
• Francesco Galeotti,
• William Porzio,
• Guido Scavia,
• Luisa Barba,
• Gianmichele Arrighetti,
• Giovanni Ricci,
• Chiara Botta and
• Umberto Giovanella

Beilstein J. Nanotechnol. 2014, 5, 2450–2458, doi:10.3762/bjnano.5.254

• cooling trigger the condensation of micrometric water droplets on the polymer solution surface, which leads to the spontaneous formation of breath figure (BF) patterns [27]. This self-assembly technique allows one to create patterned surfaces with highly regular geometry, in an custom-built

• conditions [34]. This is a clear indication that the polymer is not able to stabilize the water droplets forming at the solution/air interface, so that the microdroplets are free to float around and to coalesce in a disordered way. In order to increase the hydrophilicity of the system and hence the ability

• of the material to stabilize the water droplets, we added some free TF to the polymer solution. As soon as a minimal amount of free TF is added to the system (0.02 mg·mL−1, corresponding to 0.4% w/w with respect to the polymer hybrid), we could observe the formation of the densely packed cavities

Aquatic versus terrestrial attachment: Water makes a difference

• Petra Ditsche and
• Adam P. Summers

Beilstein J. Nanotechnol. 2014, 5, 2424–2439, doi:10.3762/bjnano.5.252

• important difference between adhesion in terrestrial and aquatic systems. Nevertheless, there are exceptions. Some terrestrial animals can step in droplets, e.g., on plant surfaces or even be completely submerged under water for a short time due to heavy rainfall. For example, the beetle Gastrophysa

Inorganic Janus particles for biomedical applications

• Isabel Schick,
• Steffen Lorenz,
• Dominik Gehrig,
• Stefan Tenzer,
• Wiebke Storck,
• Karl Fischer,
• Dennis Strand,
• Frédéric Laquai and
• Wolfgang Tremel

Beilstein J. Nanotechnol. 2014, 5, 2346–2362, doi:10.3762/bjnano.5.244

• amphiphilic particle. Kumacheva et al. reported a microfluidic method for fast continuous synthesis of Janus particles as well as three-phase particles with narrow size distribution by emulsification of monomer liquids and in situ photoinitiated polymerization of multiphase droplets (Figure 3e) [27]. Another

Liquid-phase exfoliated graphene: functionalization, characterization, and applications

• Mildred Quintana,
• Jesús Iván Tapia and
• Maurizio Prato

Beilstein J. Nanotechnol. 2014, 5, 2328–2338, doi:10.3762/bjnano.5.242

• [19]. The physical and chemical phenomena associated with ultrasonic waves are cavitation and nebulization. Cavitation induces extreme conditions by collapsing air bubbles which initiates chemical reactions, while nebulization furthers the reaction within the heated droplets. These processes induce

Biopolymer colloids for controlling and templating inorganic synthesis

• Laura C. Preiss,
• Katharina Landfester and
• Rafael Muñoz-Espí

Beilstein J. Nanotechnol. 2014, 5, 2129–2138, doi:10.3762/bjnano.5.222

• : (i) biopolymers as controlling agents of nucleation and growth of inorganic materials; (ii) biopolymers as supports, either as molecular supports or as carrier particles acting as cores of core–shell structures; and (iii) so-called “soft templates”, which include on one hand stabilized droplets

• “soft templates”, two subgroups can be considered: (C1) Biopolymer-stabilized spherical geometries (stabilized droplets, micelles, and vesicles) that confine the inorganic formation. (C2) Biopolymer structures acting as “scaffolds”, with more complex geometries than simple spheres. This is typically the

• as “soft templates” C1. Biopolymer-stabilized simple geometries (droplets, micelles, and vesicles): Surface-active polymers can assemble in solution and in heterophase systems to form defined geometries, most typically spherical, such as micelles, vesicles, or even stabilized droplets. As in the case

Effect of silver nanoparticles on human mesenchymal stem cell differentiation

• Christina Sengstock,
• Jörg Diendorf,
• Matthias Epple,
• Thomas A. Schildhauer and
• Manfred Köller

Beilstein J. Nanotechnol. 2014, 5, 2058–2069, doi:10.3762/bjnano.5.214

• to cells that were cultivated in the presence of RPMI/FCS (negative control; Figure 3A). Differentiated hMSCs changed their morphology from a fibroblast-like form (Figure 3A) to a spherical one with intracellular lipid droplets (Figure 3C). Cells that were additionally treated with 10 µg·mL−1 Ag-NP

• (Figure 3B) or 1.0 µg·mL−1 Ag+ ions (Figure 3D) revealed no significant morphological changes compared with cells cultured without silver (Figure 3C). However, a large decrease in the number of formed lipid droplets was observed in the presence of a high concentration of Ag-NP or Ag+ ions (Figure 3B and

• Figure 3D). The adipogenic differentiation of hMSCs was quantified by the optical density (520 nm) of the extracted oil red-stained lipid droplets and by phase analysis of cells stained with Bodipy493/503. As shown in Figure 4, the quantification of oil red (Figure 4A) and Bodipy493/503 (Figure 4B

The impact of the confinement of reactants on the metal distribution in bimetallic nanoparticles synthesized in reverse micelles

• Concha Tojo,
• Elena González and
• Nuria Vila-Romeu

Beilstein J. Nanotechnol. 2014, 5, 1966–1979, doi:10.3762/bjnano.5.206

• synthesize nanoparticles by this method, one reactant is solved inside the droplets of a microemulsion, and another reactant is solved inside the droplets of a second microemulsion. After mixing, the microemulsions reactants can cross intermicellar channels and come into contact when they are located inside

• mixing, the micelles move and collide, allowing reactants to come into contact with one another due to material transfer between colliding droplets. It is assumed that this intermicellar exchange occurs when a collision between two micelles results in the merger of the micelles, establishing a water

• droplets of the microemulsion can be conceived as tiny compartments or nano-reactors. The isolation of each nanoparticle inside a micelle avoids nanoparticle aggregation with particles located in nearby micelles. In this way, microemulsion droplets act as ideal templates, providing a compartmentalized

Towards bottom-up nanopatterning of Prussian blue analogues

• Virgile Trannoy,
• Marco Faustini,
• David Grosso,
• Sandra Mazerat,
• François Brisset,
• Alexandre Dazzi and
• Anne Bleuzen

Beilstein J. Nanotechnol. 2014, 5, 1933–1943, doi:10.3762/bjnano.5.204

• nanoperforated layer. This suggests a dewetting of the gold layer from the silicon surface to form gold droplets between the silicon wafer and the nanoperforated oxide layer corresponding to the light areas. The bottom of the nanoperforations in the dark areas would therefore be made of silicon rather than of

Silica nanoparticles are less toxic to human lung cells when deposited at the air–liquid interface compared to conventional submerged exposure

• Alicja Panas,
• Andreas Comouth,
• Harald Saathoff,
• Thomas Leisner,
• Marco Al-Rawi,
• Michael Simon,
• Gunnar Seemann,
• Olaf Dössel,
• Sonja Mülhopt,
• Hanns-Rudolf Paur,
• Susanne Fritsch-Decker,
• Carsten Weiss and
• Silvia Diabaté

Beilstein J. Nanotechnol. 2014, 5, 1590–1602, doi:10.3762/bjnano.5.171

• particle interactions prevent the monomers from restructuring within the atomized droplets. Hence Aerosil200 agglomerates are rather composed of irregular shaped aggregates [30] than of spherical monomers behaving like hard spheres. For this reason the actual effective density decreases with increasing

• . This value is close to the 1.8–2.2 g·cm−3 stated by the manufacturer (Postnova Analytics) and to literature data for amorphous silica particles of 2.2 g·cm−3 [43]. For agglomerates remaining from droplets containing more than one particle an effective density cannot easily be defined. For hard spheres

The study of surface wetting, nanobubbles and boundary slip with an applied voltage: A review

• Yunlu Pan,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2014, 5, 1042–1065, doi:10.3762/bjnano.5.117

• voltage are used to describe the oscillation: one is the droplet with the maximum CA, the other is the droplet with the minimum CA. Figure 8 shows the images of the droplet with different frequencies of the applied AC voltage with a peak-to-peak voltage value of 30 V. The maximum CA of the droplets are

• labeled high, and the minimum CA of the droplets are labeled low. Figure 9 shows the measured CA as a function of the frequency of the applied AC voltage. Both the high CA and the low CA remain constant, followed by a steady increase above a frequency of about 1 Hz [76]. The CAH as a function of the

Controlling mechanical properties of bio-inspired hydrogels by modulating nano-scale, inter-polymeric junctions

• Seonki Hong,
• Hyukjin Lee and
• Haeshin Lee

Beilstein J. Nanotechnol. 2014, 5, 887–894, doi:10.3762/bjnano.5.101

• gelation time through vial inversion method was typically 10–20 s. For a naccurate determination of the gelation time, we used PTFE plate setup with 45 degree slope and droplets of PEG solutions (10 µL) allowed to flow until the solutions stopped when became hydrogels. Oscillatory rheometry Oscillatory

Scale effects of nanomechanical properties and deformation behavior of Au nanoparticle and thin film using depth sensing nanoindentation

• Dave Maharaj and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2014, 5, 822–836, doi:10.3762/bjnano.5.94

• ) image (S-4300 SEM, Hitachi HTA Inc., Pleasanton, CA) of the nanoparticles. For the nanoparticle experiments conducted, several droplets of Au nanoparticles suspended in DI water were deposited onto the clean Si(100) substrates by using a syringe. A solution concentration of 0.01 mg/mL was used. The

Measuring air layer volumes retained by submerged floating-ferns Salvinia and biomimetic superhydrophobic surfaces

• Matthias J. Mayser,
• Holger F. Bohn,
• Meike Reker and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2014, 5, 812–821, doi:10.3762/bjnano.5.93

• of the surface structures (Cassie–Baxter wetting state) [13]. The contact angle of water droplets can be equally high in both wetting states [14][15]. However, in the Wenzel wetting state the water is in full contact with the surface and individual droplets adhere firmly [16]. In contrast to this in

• the Cassie wetting state the solid–water interface is strongly reduced while the majority of the interface is between water and air, thereby trapping an air layer between water and surface. As a result the adhesion of the water to the surface is minimised and individual droplets often roll off at very

Effects of the preparation method on the structure and the visible-light photocatalytic activity of Ag₂CrO₄

• Difa Xu,
• Shaowen Cao,
• Jinfeng Zhang,
• Bei Cheng and
• Jiaguo Yu

Beilstein J. Nanotechnol. 2014, 5, 658–666, doi:10.3762/bjnano.5.77

• homogeneous morphology and smaller particle size of Ag2CrO4 can be achieved since the precipitation reaction is restricted in nanosized water droplets, which are dispersed as liquid entities in a continuous oil media and act as nanoreactors for the synthesis of nanoparticles [52][53][54][55]. Furthermore

Constant-distance mode SECM as a tool to visualize local electrocatalytic activity of oxygen reduction catalysts

• Michaela Nebel,
• Thomas Erichsen and
• Wolfgang Schuhmann

Beilstein J. Nanotechnol. 2014, 5, 141–151, doi:10.3762/bjnano.5.14

• (Sigradur G, 1 mm thickness, HTW, Thierhaupten, Germany). 1 mL of the catalyst suspension consisted of 2.5 mg catalyst powder in a solution of 49.5% ethanol, 49.5% water and 1% Nafion (solution of 5 wt % Nafion from Sigma-Aldrich, Steinheim, Germany). The spot was prepared by 3200 droplets dispensing 45 pL