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

• surfactant which accumulates at the oil–water interface. The flexibility of the surfactant film surrounding micelles is a parameter associated with the interfacial curvature, which depends on the interactions on both sides of the interface. The flexibility is dictated by the microemulsion composition (mainly

• by the surfactant), and is directly related to the facility with which intermicellar channels can be established. The intermicellar exchange of material takes place through the intermicellar channel, thus the kinetics of the nanoparticle formation will strongly depend on the channel feature. Two

• aspects must be taken into account in order to establish how surfactant film flexibility is included in the simulation model. First, the material exchange between micelles will only be possible if the dimer remains intact for a sufficient amount of time. The longer that two colliding micelles stay

The surface properties of nanoparticles determine the agglomeration state and the size of the particles under physiological conditions

• Christoph Bantz,
• Olga Koshkina,
• Thomas Lang,
• Hans-Joachim Galla,
• C. James Kirkpatrick,
• Roland H. Stauber and
• Michael Maskos

Beilstein J. Nanotechnol. 2014, 5, 1774–1786, doi:10.3762/bjnano.5.188

• (organosiloxane) nanoparticles: Poly(organosiloxane) NPs are synthesized in an aqueous dispersion by co-condensation of mixtures of dialkyldialkoxysilanes and alkyltrialkoxysilanes in the presence of a surfactant. By sequential addition of mixtures with different ratios of bi- to tri-functional monomers

• nanotoxicology research: the investigation of the interaction of nanoparticles with the components of the alveolar surfactant film [71][72][73]. As the lung surfactant is the first barrier that inhaled nanoparticles encounter after passing the respiratory tract [74], interactions with this barrier are crucial in

• nanomaterial is mainly determined by three factors. The first one is the question of how the nanomaterial interacts with biological barriers. Here, interactions with the alveolar surfactant film are of special interest, because it is the first biological barrier after exposure via the lung. Therefore, the

Controlling the dispersion of supported polyoxometalate heterogeneous catalysts: impact of hybridization and the role of hydrophilicity–hydrophobicity balance and supramolecularity

• Gijo Raj,
• Colas Swalus,
• Eglantine Arendt,
• Pierre Eloy,
• Michel Devillers and
• Eric M. Gaigneaux

Beilstein J. Nanotechnol. 2014, 5, 1749–1759, doi:10.3762/bjnano.5.185

• hybrids are deposited. For instance, surfactant-encapsulated clusters of POM anions, formed through electrostatic interactions, were reported to form well-ordered straight nanorods on graphite [17], whereas hybrid materials formed through covalent functionalization of POM formed planar layer-by-layer

• surface, the alkyl chains of DODA are known to orient with a tilt angle of θ ≈ 30° with respect to the normal of the surface [30]. As expected, no epitaxial arrangement of DODA was observed. The conformation of the DODA surfactant, as shown here, can thus be tuned as a function of the surface properties

• driven through the electrostatic interaction of POM anions with the positively charged DODA surfactant. Firstly, we study the DODA–POM hybrids deposited on HOPG. Drop-casting of a small amount (about 9.5 µL) of a very dilute solution (0.025 g·L−1) allows for the formation of molecular layers that are of

Nanocrystalline ceria coatings on solid oxide fuel cell anodes: the role of organic surfactant pretreatments on coating microstructures and sulfur tolerance

• Chieh-Chun Wu,
• Ling Tang and
• Mark R. De Guire

Beilstein J. Nanotechnol. 2014, 5, 1712–1724, doi:10.3762/bjnano.5.181

• coatings from aqueous solution, were applied to anodes of solid oxide fuel cells. The cells were then operated in hydrogen/nitrogen fuel streams with H2S contents ranging from 0 to 500 ppm. Two surfactant treatments were studied: immersion in dodecanethiol, and a multi-step conversion of a siloxy-anchored

• [6][19][20][28]. In the present work the microstructural changes and the degree of sulfur tolerance were related to the presence or absence of the ceria coating, its morphology (which depended on the prior surfactant treatment), and the extent of sulfur exposure. Results First we illustrate general

• characteristics of the performance of the cells in sulfur-containing environments. Then SEM and EDXS analyses of the microstructures of the cells, before and after operation, with and without surfactant pretreatments are presented. The performance of the cells, grouped by type of anode treatment, is then

Non-covalent and reversible functionalization of carbon nanotubes

• Antonello Di Crescenzo,
• Valeria Ettorre and
• Antonella Fontana

Beilstein J. Nanotechnol. 2014, 5, 1675–1690, doi:10.3762/bjnano.5.178

• ionic surfactant such as sodium dodecyl sulfate (SDS). The chemical adsorption of SDS molecules on the surface of the nanotube induces electrostatic repulsion between polar heads that expose in the aqueous solution thus preventing CNTs aggregation and inducing the formation of stable aqueous black

• ultracentrifugation to equilibrium by exploiting a density gradient (see Figure 2) [62]. Different papers have faced the possible organizations of surfactant molecules on the surface of CNTs and still several conflicting evidences are reported in the literature. Richard et al. were among the first authors envisaging

• surfactant on the individual SWCNTs (see Figure 3, arrangement C). Analogously, we have evidenced [66][67] that gemini surfactants, characterized by two alkyl chains and two polar head groups separated by a spacer in a single molecule, are relatively effective dispersants also below their CMC or at very low

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

• , the importance of shear forces to exacerbate NP-induced toxicity has been described previously [8][33]. Another explanation could also be the secretion of surfactant by A549 cells under ALI conditions [34] which may have a protective effect due to binding of surfactant proteins to the particles [35

Growth evolution and phase transition from chalcocite to digenite in nanocrystalline copper sulfide: Morphological, optical and electrical properties

• Priscilla Vasthi Quintana-Ramirez,
• Ma. Concepción Arenas-Arrocena,
• José Santos-Cruz,
• Marina Vega-González,
• Omar Martínez-Alvarez,
• Víctor Manuel Castaño-Meneses,
• Laura Susana Acosta-Torres and
• Javier de la Fuente-Hernández

Beilstein J. Nanotechnol. 2014, 5, 1542–1552, doi:10.3762/bjnano.5.166

• from the chalcocite to the digenite phase. According to Wang et al., the growth and rearrangement of the nanodisks are dependent on the concentration of precursors, amount of surfactant, the reaction temperature, and the reaction time. We found that this rearrangement of nanodisks is necessary for the

Current state of laser synthesis of metal and alloy nanoparticles as ligand-free reference materials for nano-toxicological assays

• Christoph Rehbock,
• Jurij Jakobi,
• Lisa Gamrad,
• Selina van der Meer,
• Daniela Tiedemann,
• Ulrike Taylor,
• Wilfried Kues,
• Detlef Rath and
• Stephan Barcikowski

Beilstein J. Nanotechnol. 2014, 5, 1523–1541, doi:10.3762/bjnano.5.165

• controlled independently while their uniquely high purity is retained. Hence, this article will highlight totally surfactant-free size control strategies for laser-fabricated nanoparticles and will comment on the stability of these particles in biological fluids. Additionally, laser-based synthesis methods

In vitro interaction of colloidal nanoparticles with mammalian cells: What have we learned thus far?

• Moritz Nazarenus,
• Qian Zhang,
• Mahmoud G. Soliman,
• Pablo del Pino,
• Beatriz Pelaz,
• Susana Carregal-Romero,
• Joanna Rejman,
• Barbara Rothen-Rutishauser,
• Martin J. D. Clift,
• Reinhard Zellner,
• G. Ulrich Nienhaus,
• James B. Delehanty,
• Igor L. Medintz and
• Wolfgang J. Parak

Beilstein J. Nanotechnol. 2014, 5, 1477–1490, doi:10.3762/bjnano.5.161

• , proteins which are initially bound to the NP surface can later be replaced by others [140][141], which also is referred to as the Vroman effect [142]. It has been shown, for example, that surfactant lipids bound on multiwall carbon nanotubes are replaced with blood plasma proteins after a subsequent

• effects can result from the NPs themselves (e.g., by their catalytic surface or by their organic coating, such as in the case of cetyltrimethylammonium bromide (CTAB), a surfactant commonly used to synthesize gold nanorods) or by ions released from the NPs [154][155]. Ion release from certain materials

Protein-coated pH-responsive gold nanoparticles: Microwave-assisted synthesis and surface charge-dependent anticancer activity

• Dickson Joseph,
• Nisha Tyagi,
• Christian Geckeler and
• Kurt E.Geckeler

Beilstein J. Nanotechnol. 2014, 5, 1452–1462, doi:10.3762/bjnano.5.158

• influence on the shape of the nanoparticle [22]. We observed that, by using a single protocol, we could obtain four different gold nanostructures depending on the surfactant used for the capping. For this purpose sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTA), N-dodecyl-N,N-dimethyl-3

The protein corona protects against size- and dose-dependent toxicity of amorphous silica nanoparticles

• Dominic Docter,
• Christoph Bantz,
• Dana Westmeier,
• Hajo J. Galla,
• Qiangbin Wang,
• James C. Kirkpatrick,
• Peter Nielsen,
• Michael Maskos and
• Roland H. Stauber

Beilstein J. Nanotechnol. 2014, 5, 1380–1392, doi:10.3762/bjnano.5.151

• MTT assay (Figure 6). Similar to the lung surfactant [32], also epithelial cell of the GI tract are covered by an additional biobarrier, i.e., by mucous matrices [33]. To investigate the impact of mucus associated to GI tract cells on the observed effects, we included the mucus-secreting colorectal

• and thus, results in a reduced intracellular NP dose. However, whether reduced uptake is the (only) major determinant of the cytoprotective impact of the protein corona remains to be verified [44]. Clearly, the underlying mechanisms are not yet fully resolved. Of note, similar to the lung surfactant

Nanoporous composites prepared by a combination of SBA-15 with Mg–Al mixed oxides. Water vapor sorption properties

• Amaury Pérez-Verdejo,
• Alvaro Sampieri,
• Heriberto Pfeiffer,
• Mayra Ruiz-Reyes,
• Juana-Deisy Santamaría and
• Geolar Fetter

Beilstein J. Nanotechnol. 2014, 5, 1226–1234, doi:10.3762/bjnano.5.136

• attributed to the basic synthesis conditions. A basic medium can cause a partial destruction of the SBA-15 network [15]. Since the HT/SBA(NC) still presents the organic surfactant and TEOS during the coprecipitation of Mg and Al salts, the dissolution of the silanols species is not strongly affected by the

• that preserve the textural SBA-15 properties and also the basic properties. Indeed, Mg–Al precursors are homogenously dispersed mainly on the mesoporous SBA-15 surface. Furthermore, if the SBA-15 still contains surfactant (i.e., not calcined), the grafting through the HT coprecipitation of metal salts

Characterization and photocatalytic study of tantalum oxide nanoparticles prepared by the hydrolysis of tantalum oxo-ethoxide Ta₈(μ₃-O)₂(μ-O)₈(μ-OEt)₆(OEt)₁₄

• Subia Ambreen,
• N D Pandey,
• Peter Mayer and
• Ashutosh Pandey

Beilstein J. Nanotechnol. 2014, 5, 1082–1090, doi:10.3762/bjnano.5.121

• ) was used as the surfactant for dispersing the nanoparticles in chloroform. It was found that the nanoparticles are almost uniformly distributed. TOPO is reported to fragment bigger nanoparticles or agglomerates into smaller ones. TOPO molecules attach to the metal oxide particle surface in such a

Functionalized nanostructures for enhanced photocatalytic performance under solar light

• Liejin Guo,
• Dengwei Jing,
• Maochang Liu,
• Yubin Chen,
• Shaohua Shen,
• Jinwen Shi and
• Kai Zhang

Beilstein J. Nanotechnol. 2014, 5, 994–1004, doi:10.3762/bjnano.5.113

• microclusters with exposed {001} facets via a facile and surfactant-free hydrothermal reaction. The light absorption, charge separation and surface reaction were simultaneously optimized through the unique structure assembled from nanosheets, leading to the greatly enhanced photocatalytic activity [49]. Micro

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

• , although its XRD pattern exhibits a relatively lower intensity (Figure 1a). In our experiment, a dynamically stable and isotropic W/O reverse microemulsion system is established by using cyclohexane as oil phase, Triton X-100 as surfactant, and n-hexanol as co-surfactant, respectively. Hence a more

• , Triton X-100 serves as a nonionic surfactant in the W/O reverse microemulsion system to avoid the introduction of ionic impurities. These results suggest that the microemulsion method is superior for preparing Ag2CrO4 nanoparticles with homogenous distribution, as compared to the precipitation and

Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes

• Subas K. Muduli,
• Songling Wang,
• Shi Chen,
• Chin Fan Ng,
• Cheng Hon Alfred Huan,
• Tze Chien Sum and
• Han Sen Soo

Beilstein J. Nanotechnol. 2014, 5, 517–523, doi:10.3762/bjnano.5.60

• Polycrystalline Ce7O12 samples have been previously synthesized, but harsh conditions (up to 1030 °C) by reduction of CeO2 with CO were employed [25][26]. Instead, mild, surfactant-free solvothermal conditions were used to prepare mesoporous cerium oxide with oxygen vacancies. A solution of ceric ammonium nitrate

One-step synthesis of high quality kesterite Cu₂ZnSnS₄ nanocrystals – a hydrothermal approach

• Vincent Tiing Tiong,
• John Bell and
• Hongxia Wang

Beilstein J. Nanotechnol. 2014, 5, 438–446, doi:10.3762/bjnano.5.51

• , pure kesterite phase CZTS nanocrystals with uniform size distribution have been successfully synthesized by a facile one-step hydrothermal route based on a precursor solution containing thioglycolic acid (TGA) as surfactant. The role of TGA in the hydrothermal reaction is clarified and a formation

Preparation of poly(N-vinylpyrrolidone)-stabilized ZnO colloid nanoparticles

• Tatyana Gutul,
• Emil Rusu,
• Nadejda Condur,
• Veaceslav Ursaki,
• Evgenii Goncearenco and
• Paulina Vlazan

Beilstein J. Nanotechnol. 2014, 5, 402–406, doi:10.3762/bjnano.5.47

• was precipitated and washed with absolute ethanol several times after cooling to room temperature. The excess surfactant, unreacted precursor, and high-boiling point solvents were removed by means of a solvent containing hexane, anhydrous ethanol, and acetone in the proportion of 2:1:5 [14

Manipulation of nanoparticles of different shapes inside a scanning electron microscope

• Boris Polyakov,
• Sergei Vlassov,
• Leonid M. Dorogin,
• Jelena Butikova,
• Mikk Antsov,
• Sven Oras,
• Rünno Lõhmus and
• Ilmar Kink

Beilstein J. Nanotechnol. 2014, 5, 133–140, doi:10.3762/bjnano.5.13

• onto oxidized silicon wafers (Semiconductor Wafer Inc., 50 nm of thermal oxide). The samples were annealed for 1 h at 500 °C prior to every experiment to remove the surfactant. Rounded Ag NPs were produced by laser-induced (532 nm, Expla, NL200) partial melting [19] of pentagonal Ag nanowires (Blue

• other shapes can be identified in the SEM image (Figure 2b). Some particles exhibit truncated edges and apexes. Typical morphologies of Au NPs are listed in Table 1. It should be noted, that after the removal of the surfactant by thermal treatment partial rounding of the particles might occur [20]. The

Cytotoxic and proinflammatory effects of PVP-coated silver nanoparticles after intratracheal instillation in rats

• Nadine Haberl,
• Stephanie Hirn,
• Alexander Wenk,
• Jörg Diendorf,
• Matthias Epple,
• Blair D. Johnston,
• Fritz Krombach,
• Wolfgang G. Kreyling and
• Carsten Schleh

Beilstein J. Nanotechnol. 2013, 4, 933–940, doi:10.3762/bjnano.4.105

• alveolar region [10][11][12]. Once deposited there, nanoparticles are found to interact with the epithelial lining fluid including pulmonary surfactant, lung macrophages and epithelial cells [13][14][15]. Depending on their physico-chemical properties, a small portion of the inhaled nanomaterials may even

Controlled synthesis and tunable properties of ultrathin silica nanotubes through spontaneous polycondensation on polyamine fibrils

• Jian-Jun Yuan,
• Pei-Xin Zhu,
• Daisuke Noda and
• Ren-Hua Jin

Beilstein J. Nanotechnol. 2013, 4, 793–804, doi:10.3762/bjnano.4.90

• may collapse upon calcination at temperatures higher than 750 °C [40]. Regarding this, it should be noted that the conventional surfactant-based sol–gel reaction is catalyzed by HCl or NaOH. In this system, the silica sol forms in aqueous solution and then subsequently precipitates within the space of

• reports on the carbonization of porous silica–polymer [47] and organosilica/surfactant composites [48][49]. However, the synthesis of silica–carbon composite nanotube materials is still very rare. Liu and co-workers [50] have recently reported the fabrication of silica–carbon nanotubes by carbonization of

Structural, optical and photocatalytic properties of flower-like ZnO nanostructures prepared by a facile wet chemical method

• Sini Kuriakose,
• Neha Bhardwaj,
• Jaspal Singh,
• Biswarup Satpati and
• Satyabrata Mohapatra

Beilstein J. Nanotechnol. 2013, 4, 763–770, doi:10.3762/bjnano.4.87

• synthesized by Umar et al. [31] for an efficient photocatalysis and the fabrication of efficient dye sensitized solar cells. Shi et al. [33] fabricated flower-like ZnO on ZnO nanorods without use of any surfactant. Self-supported ZnO photocatalysts in the form of plates were prepared by Yassitepe et al. [24

Large-scale atomistic and quantum-mechanical simulations of a Nafion membrane: Morphology, proton solvation and charge transport

• Pavel V. Komarov,
• Pavel G. Khalatur and
• Alexei R. Khokhlov

Beilstein J. Nanotechnol. 2013, 4, 567–587, doi:10.3762/bjnano.4.65

• the minority component [66]. Possible bicontinuous architectures are naturally associated with well known bicontinuous cubic phases (BCPs). Among many BCPs found in block copolymers and concentrated surfactant systems, the double-diamond (DD) structure with the space group , and the Schoen's double

• than in H- or P-bulk phase. This means that the HP unit possesses a significant surface activity and behaves as an interface modifier (surfactant). This behavior should be seen particularly clearly in the presence of one more polar component, namely water. The tendency to form interfaces between

Nanoscopic surfactant behavior of the porin MspA in aqueous media

• Ayomi S. Perera,
• Hongwang Wang,
• Tej B. Shrestha,
• Deryl L. Troyer and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2013, 4, 278–284, doi:10.3762/bjnano.4.30

• that MspA behaves like a nanoscale surfactant. The extreme thermostability of MspA allows these investigations to be carried out at temperatures as high as 343 K, at which most other proteins would quickly denature. The principles of vesicle formation of MspA as a function of temperature and the

• underlying thermodynamic factors are discussed here. The results obtained provide crucial evidence in support of the hypothesis that, during vesicle formation, nanoscopic surfactant molecules, such as MspA, deviate from the principles underlined in classical surface chemistry. Keywords: charge-interaction

• behavior of MspA in aqueous buffers, further expanding the pioneering work of Engelhardt et al. In 1× PBS (phosphate-buffered saline), MspA is capable of forming vesicles in the absence of added surfactant. Owing to the great thermal stability of MspA [3], we were able to study the influence of ionic

Sub-10 nm colloidal lithography for circuit-integrated spin-photo-electronic devices

• Adrian Iovan,
• Marco Fischer,
• Roberto Lo Conte and
• Vladislav Korenivski

Beilstein J. Nanotechnol. 2012, 3, 884–892, doi:10.3762/bjnano.3.98

• for two minutes in order to make the surface hydrophilic [31]. As an alternative route, we found that a good quality monolayer, with a well-defined long-range order, can be obtained if a small amount of Triton X surfactant [32] is added into the colloidal solution. However, the subsequent extensive