Reasons and remedies for the agglomeration of multilayered graphene and carbon nanotubes in polymers

• Rasheed Atif and
• Fawad Inam

Beilstein J. Nanotechnol. 2016, 7, 1174–1196, doi:10.3762/bjnano.7.109

• mechanical stirring, to disentangle the nano-filler followed by the enclosure of dispersed nano-filler in a polymer matrix or a surfactant complex. This enclosure hinders the re-aggregation and yields a metastable dispersion. Or the nano-filler is disentangled by dispersion in a suitable solvent. In the case

• surfactant solution. The reactions involved are carried out in argon atmosphere [117]. A typical disorder band in Raman spectrum gives proof of the sidewall functionalization. This sidewall functionalization not only improves purity and solubility, but it also changes the physical properties. In fact, the

• driving force for the formation of aggregates. The CNT dispersion can be enhanced by non-ionic surfactants in case of water-soluble polymers [40]. Both ionic and non-ionic aqueous surfactant solutions can be used to disperse the CNT in low concentrations. Examples of surfactants include sodium

An ellipsometric approach towards the description of inhomogeneous polymer-based Langmuir layers

• Falko O. Rottke,
• Burkhard Schulz,
• Klaus Richau,
• Karl Kratz and
• Andreas Lendlein

Beilstein J. Nanotechnol. 2016, 7, 1156–1165, doi:10.3762/bjnano.7.107

• will observe lateral movement for almost every surfactant film. This movement originates from thermal and/or surface pressure gradients or even from air draft. This movement does not significantly hinder the recording of a fully focused IE or BAM image, which takes about one second; whereas it takes

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• reaction by-products typical of nonaqueous sol–gel routes using precursors that do not contain hydrate species. Here, the amine species capping acts not only as a surfactant but also as a shape and size controlling agent during growth of the NP. Since our MWCNTs were not acid treated, the particles are

Synthesis of cobalt nanowires in aqueous solution under an external magnetic field

• Xiaoyu Li,
• Lijuan Sun,
• Hu Wang,
• Kenan Xie,
• Qin Long,
• Xuefei Lai and
• Li Liao

Beilstein J. Nanotechnol. 2016, 7, 990–994, doi:10.3762/bjnano.7.91

• pressures, cobalt nanowires were synthesized by chemical reduction in aqueous solution with the assistance of polyvinylpyrrolidone (PVP) as surfactant under moderate conditions for the first time, while an external magnetic field of 40 mT was applied. Uniform linear cobalt nanowires with relatively smooth

• . Keywords: aqueous solution; cobalt nanowires; external magnetic field; magnetic properties; surfactant; Findings In recent years, cobalt nanowires, as a ferromagnetic material, have attracted considerable attention due to their outstanding magnetic properties and excellent performance in applications in

• preparing cobalt nanowires in aqueous solution up to now [13]. In our previous studies, we have successfully prepared nickel and nickel/copper nanowires [14][15][16], and cobalt nanowires were synthesized using NaBH4 as initiator without surfactant in ethylene glycol solution with an external magnetic field

Reconstitution of the membrane protein OmpF into biomimetic block copolymer–phospholipid hybrid membranes

• Matthias Bieligmeyer,
• Franjo Artukovic,
• Stephan Nussberger,
• Thomas Hirth,
• Thomas Schiestel and
• Michaela Müller

Beilstein J. Nanotechnol. 2016, 7, 881–892, doi:10.3762/bjnano.7.80

• (0.01% w/v) is below its cmc value and a channel-like structure, formed by the surfactant is very unlikely. Current fluctuations through single and multiple channels were recorded in voltage-clamp mode using an Axon Axopatch 200B amplifier (Molecular Devices, Sunnyvale, USA) with a capacitive headstage

The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures

• Yevgeniy R. Davletshin and
• J. Carl Kumaradas

Beilstein J. Nanotechnol. 2016, 7, 869–880, doi:10.3762/bjnano.7.79

• account for separation by surfactant or coupling molecules on the particles surface while still keeping a strong plasmonic coupling effect [43]. The 3D geometry was reduced to one quarter of the full geometry (see Figure 1) by utilizing symmetry planes and absorbing boundary conditions. PEC and PMC

Direct formation of gold nanorods on surfaces using polymer-immobilised gold seeds

• Majid K. Abyaneh,
• Pietro Parisse and
• Loredana Casalis

Beilstein J. Nanotechnol. 2016, 7, 809–816, doi:10.3762/bjnano.7.72

• “seed solution” containing small gold nanoparticles is added to a “growth solution” in which particles grow by slow diffusion of gold atoms onto the surface of the seeds to form GNRs. The growth solution contains Au(III) ions, a reducing agent and a surfactant. Many efforts also have been made to align

• size and preferred growth planes of {111}. On the other hand, it is proposed [40] that cetyltrimethylammonium bromide (CTAB), used as a surfactant in this work, has a preferential binding to specific side faces of gold particles, slowing down the nucleation on these side planes and allowing growth of

• -reduction procedure without using any surfactant, capping agent or reducing agent in the solid form. Fabrication of Au–PMMA nanocomposites using UV irradiation has been reported previously in [30]. Briefly, PMMA with two different molecular weights, Mw, was chosen (P1 with Mw = 120 kDa, d = 1.188 and P2

Assembling semiconducting molecules by covalent attachment to a lamellar crystalline polymer substrate

• Rainhard Machatschek,
• Patrick Ortmann,
• Renate Reiter,
• Stefan Mecking and
• Günter Reiter

Beilstein J. Nanotechnol. 2016, 7, 784–798, doi:10.3762/bjnano.7.70

• process [7][11], we refrained from adding surfactants as we wanted to avoid to have surfactant molecules included in the monolayers transferred onto a solid substrate. Accordingly, we spread CPE45 nanocrystals from a 1:1 methanol–water dispersion onto a water surface at pH 11. After Langmuir–Schäfer

Magnetic switching of nanoscale antidot lattices

• Ulf Wiedwald,
• Joachim Gräfe,
• Kristof M. Lebecki,
• Maxim Skripnik,
• Felix Haering,
• Gisela Schütz,
• Paul Ziemann,
• Eberhard Goering and
• Ulrich Nowak

Beilstein J. Nanotechnol. 2016, 7, 733–750, doi:10.3762/bjnano.7.65

Tight junction between endothelial cells: the interaction between nanoparticles and blood vessels

• Yue Zhang and
• Wan-Xi Yang

Beilstein J. Nanotechnol. 2016, 7, 675–684, doi:10.3762/bjnano.7.60

• equilibrium molecular dynamics simulations [84]. An experimental investigation showed a positive correlation between the concentration of Cu nanoparticles and the viscosity of viscoelastic surfactant solutions [85]. Interestingly, viscoelastic nanofluids containing multiwalled carbon nanotubes also showed non

Gold nanoparticles covalently assembled onto vesicle structures as possible biosensing platform

• M. Fátima Barroso,
• M. Alejandra Luna,
• Juan S. Flores Tabares,
• Cristina Delerue-Matos,
• N. Mariano Correa,
• Fernando Moyano and
• Patricia G. Molina

Beilstein J. Nanotechnol. 2016, 7, 655–663, doi:10.3762/bjnano.7.58

• process of FeCl2 and FeCl3. Using an adsorptive process the vesicles structure was incorporated with super-paramagnetic iron oxide nanoparticles [7]. Additionally, the molecular deposition of silica from water was carried out [8]. Silica-coated unilamellar surfactant vesicles were prepared by hydrolysis

Characterisation of thin films of graphene–surfactant composites produced through a novel semi-automated method

• Nik J. Walch,
• Alexei Nabok,
• Frank Davis and
• Séamus P. J. Higson

Beilstein J. Nanotechnol. 2016, 7, 209–219, doi:10.3762/bjnano.7.19

• bromide (CTAB). The formation of individual graphene flakes was confirmed by Raman spectroscopy, while the interaction of graphene with surfactants was proven by NMR spectroscopy. The resulting graphene–surfactant composite material formed a stable suspension in water and some organic solvents, such as

• -coated glass using a method of total internal reflection ellipsometry (TIRE) which revealed the enhancement of the surface plasmon resonance in thin gold films by depositing graphene layers. Keywords: characterization; ellipsometry; graphene; 1H NMR; surfactant; Introduction Since its initial discovery

• sensor applications, for use in flexible electronics [2] and graphene-based printable inks for printed electrical circuits [3]. Graphene has reportedly been produced in a number of different ways. The method chosen for this research is sonochemical exfoliation in water in the presence of a surfactant, as

Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2016, 7, 22–31, doi:10.3762/bjnano.7.3

• completely removed after the annealing at higher temperature. Moreover, after the annealing the carbon percentage decreased, confirming that all the surfactant shell was partially (at 300 °C) or almost completely (at 550 °C) removed trough thermal annealing. The total amount of elemental gold (Au0) deposited

Two step formation of metal aggregates by surface X-ray radiolysis under Langmuir monolayers: 2D followed by 3D growth

• Smita Mukherjee,
• Marie-Claude Fauré,
• Michel Goldmann and
• Philippe Fontaine

Beilstein J. Nanotechnol. 2015, 6, 2406–2411, doi:10.3762/bjnano.6.247

• -assembly properties of surfactant molecules in solution. By the choice of the organic molecule, we can tune the surface charge of the formed self-assembly in order to attract the ions in their vicinity. Therefore, we expect that during the irradiation process, the aggregation of the reduced atoms takes

• were able to form a dense, metallic silver layer anchored underneath an organic monolayer by irradiating with an X-ray beam in grazing incidence geometry, a Langmuir monolayer (mono-molecular layer of insoluble surfactant molecules) deposited on the free surface of a silver-ion aqueous solution. The

Surfactant-controlled composition and crystal structure of manganese(II) sulfide nanocrystals prepared by solvothermal synthesis

• Elena Capetti,
• Anna M. Ferretti,
• Vladimiro Dal Santo and
• Alessandro Ponti

Beilstein J. Nanotechnol. 2015, 6, 2319–2329, doi:10.3762/bjnano.6.238

• Ricerche, via C. Golgi 19, 20133 Milano, Italy 10.3762/bjnano.6.238 Abstract We investigated how the outcome of the solvothermal synthesis of manganese(II) sulfide (MnS) nanocrystals (NCs) is affected by the type and amount of long chain surfactant present in the reaction mixture. Prompted by a previous

• sulfur and carboxylic acid. MnS NCs were obtained provided that the S/Mn ratio was larger than the L/Mn ratio, otherwise MnO NCs were produced. Since MnS can crystallize in three distinct phases (rock salt α-MnS, zincblende β-MnS, and wurtzite γ-MnS), we also investigated whether the surfactant affected

• the NC polymorphism. We found that MnS polymorphism can be controlled by appropriate selection of the surfactant. γ-MnS nanocrystals formed when a 1:2 mixture of long chain carboxylic acid and amine was used, irrespective of the presence of carboxylic acid as a free surfactant or ligand in the metal

Green synthesis, characterization and catalytic activity of natural bentonite-supported copper nanoparticles for the solvent-free synthesis of 1-substituted 1H-1,2,3,4-tetrazoles and reduction of 4-nitrophenol

• Akbar Rostami-Vartooni,
• Mohammad Alizadeh and
• Mojtaba Bagherzadeh

Beilstein J. Nanotechnol. 2015, 6, 2300–2309, doi:10.3762/bjnano.6.236

• NPs/bentonite The Cu NPs/bentonite composite was prepared by a simple and inexpensive method involving the immobilization of Cu NPs on bentonite using an aqueous extract of Thymus vulgaris without the usage of any special capping agents or surfactant template. The plant not only functioned as a

Silica-coated upconversion lanthanide nanoparticles: The effect of crystal design on morphology, structure and optical properties

• Uliana Kostiv,
• Miroslav Šlouf,
• Hana Macková,
• Alexander Zhigunov,
• Hana Engstová,
• Katarína Smolková,
• Petr Ježek and
• Daniel Horák

Beilstein J. Nanotechnol. 2015, 6, 2290–2299, doi:10.3762/bjnano.6.235

• then added, and the mixture was stirred (600 rpm) at room temperature for 2 days. The resulting NaYF4:Yb3+/Er3+&SiO2 nanoparticles were precipitated by the addition of acetone (10 mL), separated by centrifugation and washed five times with ethanol and ethanol/water (1:1 v/v) to remove the surfactant

Nanofibers for drug delivery – incorporation and release of model molecules, influence of molecular weight and polymer structure

• Jakub Hrib,
• Jakub Sirc,
• Radka Hobzova,
• Zuzana Hampejsova,
• Zuzana Bosakova,
• Marcela Munzarova and
• Jiri Michalek

Beilstein J. Nanotechnol. 2015, 6, 1939–1945, doi:10.3762/bjnano.6.198

• molecular weights of 2,000, 6,000, 10,000 and 20,000 g/mol were selected as model molecules. Polyethylene glycol (PEG) is a hydrophilic polyether commercially available in various molecular weights with narrow distribution. It is widely used in various medical applications, for example as surfactant

Temperature-dependent breakdown of hydrogen peroxide-treated ZnO and TiO₂ nanoparticle agglomerates

• Sinan Sabuncu and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 1897–1903, doi:10.3762/bjnano.6.193

• treating them with hydrogen peroxide and heating up to 90 °C was demonstrated. The ZnO and TiO2 NPs were successfully dispersed in aqueous media without using a surfactant or other dispersing agents. Since H2O2 is decomposed into H2O and O2 during the NP treatment, the process is environmentally friendly

PLGA nanoparticles as a platform for vitamin D-based cancer therapy

• Maria J. Ramalho,
• Joana A. Loureiro,
• Bárbara Gomes,
• Manuela F. Frasco,
• Manuel A. N. Coelho and
• M. Carmo Pereira

Beilstein J. Nanotechnol. 2015, 6, 1306–1318, doi:10.3762/bjnano.6.135

• electrostatic forces due to the PLGA carboxylate groups at the NP surface, and the surfactant behavior that also plays a crucial role in maintaining nanosuspension stabilization. During particle formation, the Pluronic®F127 is adsorbed onto the NP surface, providing steric and thermodynamic stabilization

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

• duration, and laser fluence) and the properties of the environment (e.g., surfactant concentration, pH value, or size and length of ligands) [1][2][3][4][5][6]. Laser ablation is an explosive material removal process using strong pulsed-laser irradiation. The LAL process causes the ejection of nanoclusters

A simple approach to the synthesis of Cu_1.8S dendrites with thiamine hydrochloride as a sulfur source and structure-directing agent

• Xiaoliang Yan,
• Sha Li,
• Yun-xiang Pan,
• Zhi Yang and
• Xuguang Liu

Beilstein J. Nanotechnol. 2015, 6, 881–885, doi:10.3762/bjnano.6.90

• nitrate and thiamine hydrochloride were selected as the starting materials in the water phase under hydrothermal conditions. No addition of a surfactant or a complex reagent was required for the synthesis of the Cu1.8S dendrite structures. Thiamine hydrochloride was employed as a sulfur source and

Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

• Shanka Walia and
• Amitabha Acharya

Beilstein J. Nanotechnol. 2015, 6, 546–558, doi:10.3762/bjnano.6.57

• trimethylammonium bromide (CTAB), butanol and hexane as surfactant, co-surfactant and oil phase, respectively. The silica coating of the Gd2(CO3)3:Tb complex was done by using tetraethylorthosilicate (TEOS) under ammonical conditions. The synthesized NPs were characterized by HRTEM, EDX and FTIR. The size of the

• synthesis was enhanced by using Y(NO3)3·6H2O and Eu2O3 as reactants, CTAB as surfactant and TEOS as alkyl silicate. Finally, the anticancer drug doxyrubicin (DOX) was loaded into the prepared NPs. Characterization of mesoporous silica NPs (MSN), YVO4:Eu3+ NPs and YVO4-MSNs were done by XRD, FTIR, TEM and

• -shell-encapsulated hybrid nanomaterials consisting of paramagnetic Gd3+ ions and QDs or Au nanocrystals. The citric-acid-capped gold colloids and CdSe/ZnS QDs were silanized by using mercaptopropyltrimethoxysilane (MPS) as surfactant. Further, a Gd3+-DOTA (tetraazacyclododecanetetraacetic acid) complex

Pulmonary surfactant augments cytotoxicity of silica nanoparticles: Studies on an in vitro air–blood barrier model

• Jennifer Y. Kasper,
• Lisa Feiden,
• Maria I. Hermanns,
• Christoph Bantz,
• Michael Maskos,
• Ronald E. Unger and
• C. James Kirkpatrick

Beilstein J. Nanotechnol. 2015, 6, 517–528, doi:10.3762/bjnano.6.54

• to investigate the potential hazard of NPs. However, in most in vitro studies a crucial alveolar component has been neglected. Before aspirated NPs encounter the cellular air–blood barrier, they impinge on the alveolar surfactant layer (10–20 nm in thickness) that lines the entire alveolar surface

• . Thus, a prior interaction of NPs with pulmonary surfactant components will occur. In the present study we explored the impact of pulmonary surfactant on the cytotoxic potential of amorphous silica nanoparticles (aSNPs) using in vitro mono- and complex coculture models of the air–blood barrier

• . Furthermore, different surface functionalisations (plain-unmodified, amino, carboxylate) of the aSNPs were compared in order to study the impact of chemical surface properties on aSNP cytotoxicity in combination with lung surfactant. The alveolar epithelial cell line A549 was used in mono- and in coculture

Conformal SiO₂ coating of sub-100 nm diameter channels of polycarbonate etched ion-track channels by atomic layer deposition

• Nicolas Sobel,
• Christian Hess,
• Manuela Lukas,
• Anne Spende,
• Bernd Stühn,
• M. E. Toimil-Molares and
• Christina Trautmann

Beilstein J. Nanotechnol. 2015, 6, 472–479, doi:10.3762/bjnano.6.48

• narrow size distribution [4][5][6]. Typically, polymers such as polycarbonate (PC), polyethylene terephthalate, and polyimide are employed as templates. Hydrophilicity is sometimes improved by immersing the etched membrane in a surfactant solution such as polyvinylpyrrolidone. The addition of surfactants