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

• dispersion state of filler as multilayered graphene (MLG) and carbon nanotubes (CNTs) tend to agglomerate due to van der Waals forces. The agglomeration can be avoided by using organic solvents, selecting suitable dispersion and production methods, and functionalizing the fillers. Another proposed method is

• the use of hybrid fillers as synergistic effects can cause an improvement in the dispersion state of the fillers. In this review article, various aspects of each process that can help avoid filler agglomeration and improve dispersion state are discussed in detail. This review article would be helpful

• for both current and prospective researchers in the field of MLG- and CNT-based polymer nanocomposites to achieve maximum enhancement in mechanical, thermal, and electrical properties of produced polymer nanocomposites. Keywords: agglomeration; carbon nanotubes (CNTs); dispersion state; multilayered

Multiwalled carbon nanotube hybrids as MRI contrast agents

• Nikodem Kuźnik and
• Mateusz M. Tomczyk

Beilstein J. Nanotechnol. 2016, 7, 1086–1103, doi:10.3762/bjnano.7.102

• agglomeration, while the lipophilic surface of the MWCNT has sufficiently high affinity to the cell membrane for permanent connections. Chen subjected pristine MWCNT to LBL (layer-by-layer) non-covalent functionalizations with the polyelectrolyte poly(allylamine hydrochloride) (PAH) followed by silica coating

• °C) allowed for the production of hybrids uniformly coated with metallic superparamagnets, yet an increased temperature was responsible for agglomeration of the nanoparticles on the nanotube walls. Yin, finally, presented a method of SPIO deposition by thermal decomposition of ferrocene under aerobic

• micelle formation as a mechanism of preventing MWCNT from agglomeration and sedimentation with a critical micelle concentration (cmc) equal to 0.06 mM. On the other hand, in the course of Richard’s studies it was found that Gd-L1 adsorption on the nanotube takes place, thus also this form is adequate for

Development of highly faceted reduced graphene oxide-coated copper oxide and copper nanoparticles on a copper foil surface

• Rebeca Ortega-Amaya,
• Yasuhiro Matsumoto,
• Andrés M. Espinoza-Rivas,
• Manuel A. Pérez-Guzmán and
• Mauricio Ortega-López

Beilstein J. Nanotechnol. 2016, 7, 1010–1017, doi:10.3762/bjnano.7.93

• , (c) surface diffusion, (d) agglomeration and (e) coalescence of adjacent NPs. (f) At the partially melted Cu surface, rGO sheets self-assemble to develop the rGO coating. (g) Equilibrium crystal shape of representative rGO-CuNPs at 1000 °C. FE-SEM images picturing the steps described above: (d1

• ) agglomeration, (e1), coalescence (circle) and (g1) equilibrium crystal shape. Note that, at annealing temperatures of 800–1000 °C, copper oxide transforms into copper via reduction by CO (Cu2O + CO → 2Cu + CO2). (a) TEM image of a sample annealed at 800 °C for 1 h. (b,c) Low- and high-magnification FE-SEM. (d

Improved biocompatibility and efficient labeling of neural stem cells with poly(L-lysine)-coated maghemite nanoparticles

• Igor M. Pongrac,
• Marina Dobrivojević,
• Lada Brkić Ahmed,
• Michal Babič,
• Miroslav Šlouf,
• Daniel Horák and
• Srećko Gajović

Beilstein J. Nanotechnol. 2016, 7, 926–936, doi:10.3762/bjnano.7.84

• tracking [16]. Biocompatible polymers are used to modify the surface of nanoparticles, prevent their agglomeration and facilitate internalization. The most widely used coating for surface modification of nanoparticles is dextran, which promotes nanoparticle internalization, in particular in different

• of both types of the nanoparticles occurred via macropinocytosis as confirmed by TEM. Recently, PLL-γ-Fe2O3 agglomeration properties were studied in biological cell culture media with or without common serum protein, which showed the increase of size and negative ζ-potential in comparison to

• , Great Britain). The agglomeration properties and the surface charge properties of PLL-γ-Fe2O3 nanoparticles in biological cell culture medium with and without addition of common serum protein were previously described [26]. The crystal structure of both types of nanoparticles was investigated using the

Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field

• Amanda García-García,
• Ricardo Vergaz,
• José F. Algorri,
• Gianluigi Zito,
• Teresa Cacace,
• Antigone Marino,
• José M. Otón and
• Morten A. Geday

Beilstein J. Nanotechnol. 2016, 7, 825–833, doi:10.3762/bjnano.7.74

• SWCNT orientation is detected at all (Figure 6). This lack of reversibility can be linked to agglomeration, or imperfect dispersion, of the nanotubes. The agglomerates may become so large that the anchoring force that the LC exerts is not sufficient to realign the agglomerate, or they may even become

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

• formed by UV photoreduction. PMMA has amazing properties such as transparency, flexibility and light weight. Moreover, it is able to immobilise the nanoparticles avoiding their agglomeration and thus maintaining the novel size-dependent properties of nanomaterials. PMMA is widely used in lithography and

• with a wide distribution (±500 nm). The average distance for the P2-60 nanocomposite is 180 nm with a narrower distribution (±50 nm). In all samples, the gold nanoparticles are well dispersed in the polymer matrix and no agglomeration is observed. These well-dispersed and protruded gold nanoparticles

Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles

• Jacek Wojnarowicz,
• Roman Mukhovskyi,
• Elzbieta Pietrzykowska,
• Sylwia Kusnieruk,
• Jan Mizeracki and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2016, 7, 721–732, doi:10.3762/bjnano.7.64

• employed methods. The lack of simultaneous control over chemical composition, stoichiometry, dopant homogeneity, particle size distribution, shape, phase purity, surface modification and agglomeration, makes it difficult to obtain NPs [22]. The primary cause of the lack of reproducibility of magnetic

• content, high efficiency, and surface modification [47]. MSS products are characterised by homogeneous morphology, purity, narrow size distribution and low agglomeration. The present paper contains an attempt to obtain ZnO nanoparticles with a Mn2+ dopant content of up to 25 mol %. For the synthesis we

• agglomeration and formation of conglomerates of Zn1−xMnxO NPs. Phase composition The XRD tests of the samples did not reveal a presence of foreign phases in the obtained Zn1−xMnxO NPs, and all diffraction peaks can be attributed to the hexagonal phase ZnO (Figure 5). Zinc oxide is characterised by hexagonal

Fabrication and properties of luminescence polymer composites with erbium/ytterbium oxides and gold nanoparticles

• Julia A. Burunkova,
• Ihor Yu. Denisiuk,
• Dmitri I. Zhuk,
• Lajos Daroczi,
• Attila Csik,
• István Csarnovics and
• Sándor Kokenyesi

Beilstein J. Nanotechnol. 2016, 7, 630–636, doi:10.3762/bjnano.7.55

• macroscopic elements. At the same time one of the main disadvantages of nanocomposites is the high level of light scattering, which can be caused by agglomeration of nanoparticles. So the development of low-scattering, transparent nanocomposites is an important challenge nowadays. The method of thermal

• decomposition of rare earth salts is usually used for the fabrication of luminescent rare earth oxide (REO) nanoparticles [3]. Unfortunately, the agglomeration of nanoparticles during high temperature annealing (above 900 °C) causes a high level of light scattering in the nanocomposite made from these materials

• chlorides [9] for the fabrication of Er/Yb oxide nanoparticles with defined parameters and without agglomeration, and the fabrication of optically transparent nanocomposites on their basis in selected polymer matrices with tunable luminescent parameters. Introduction of preformed gold nanoparticles and

Surface coating affects behavior of metallic nanoparticles in a biological environment

• Darija Domazet Jurašin,
• Marija Ćurlin,
• Ivona Capjak,
• Tea Crnković,
• Marija Lovrić,
• Michal Babič,
• Daniel Horák,
• Ivana Vinković Vrček and
• Srećko Gajović

Beilstein J. Nanotechnol. 2016, 7, 246–262, doi:10.3762/bjnano.7.23

• fluids [19][20][21][22][23][24][25][26][27]. NP agglomeration is intended in some applications, such as in immunoassays [28], while many others require stable colloidal dispersions of NPs at high physiological ionic strength [29]. Stabilization of metallic NPs at high electrolyte content, i.e., in

• biological media, may be achieved by electrostatic or steric repulsions [30][31][32]. Various types of surface coatings have been shown to affect NP properties, particularly to improve their biocompatibility and stability against agglomeration [30][33][34][35]. Proteins or biologically-compatible surfactants

• may serve as desirable barriers preventing NPs from agglomeration in biomedical applications [18]. Moreover, when NPs enter a biological fluid, electrostatic, dispersive, and covalent interactions cause proteins to adsorb on NP surfaces, leading to the formation of a dynamic protein corona [30][36][37

Linear and nonlinear optical properties of hybrid metallic–dielectric plasmonic nanoantennas

• Mario Hentschel,
• Bernd Metzger,
• Bastian Knabe,
• Karsten Buse and
• Harald Giessen

Beilstein J. Nanotechnol. 2016, 7, 111–120, doi:10.3762/bjnano.7.13

• depicts a tilted-view SEM micrograph of a single gold bowtie nanoantenna. One can clearly see the nanocrystals that have agglomerated in the gap region. In Figure 2b, additional SEM micrographs of the fabricated structures are shown. In order to track the agglomeration using an optical microscope, large

Chemical bath deposition of textured and compact zinc oxide thin films on vinyl-terminated polystyrene brushes

• Nina J. Blumenstein,
• Caroline G. Hofmeister,
• Peter Lindemann,
• Cheng Huang,
• Johannes Baier,
• Andreas Leineweber,
• Stefan Walheim,
• Christof Wöll,
• Thomas Schimmel and
• Joachim Bill

Beilstein J. Nanotechnol. 2016, 7, 102–110, doi:10.3762/bjnano.7.12

• at a flow rate of 1.044 mL·min−1 under gentle stirring. The reaction solution was prepared anew every day to prevent agglomeration of particles. The functionalized Si wafers and the reference samples without brush were immersed in 1 mL of the precursor solution in a closed vessel, each. The vessels

Green and energy-efficient methods for the production of metallic nanoparticles

• Mitra Naghdi,
• Mehrdad Taheran,
• Satinder K. Brar,
• M. Verma,
• R. Y. Surampalli and
• J. R. Valero

Beilstein J. Nanotechnol. 2015, 6, 2354–2376, doi:10.3762/bjnano.6.243

• methods involve the use of dispersants, surfactants or chelating agents to prevent the agglomeration of particles. Most of these reagents can be considered environmental pollutants, if they are going to be used in large scale production [16]. As a consequence, there have been growing concerns about the

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

• spherical morphology with a low tendency for agglomeration. Figure 6d (SAED) shows the measured selected area electron diffraction pattern of as-prepared Cu NPs/bentonite. This result indicates that the nanoparticles are crystalline and mainly composed of fcc Cu. The SAED patterns of the Cu NPs/bentonite

An adapted Coffey model for studying susceptibility losses in interacting magnetic nanoparticles

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2015, 6, 2173–2182, doi:10.3762/bjnano.6.223

• , magnetite is considered the most favourable material in magnetic hyperthermia. At about 30 nm particle diameter the behaviour of magnetite nanoparticles changes from single-domain to multi-domain state [7], representing the critical dimension of magnetite-based nanoparticles. The tendency for agglomeration

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

• devices due to their unique physicochemical properties. One of the major problems with their widespread implementation is their uncontrolled agglomeration. One approach to reduce agglomeration is to alter their surface chemistry with a proper functionality in an environmentally friendly way. In this study

• individual nanoparticles. It was shown that the combined effect of hydroxylation and heating enhances the dispersion of ZnO and TiO2 NPs in water. Keywords: agglomeration; hydrogen peroxide; metal oxide nanoparticles; TiO2; ZnO; Introduction Dispersion of metal oxide nanoparticles (MONPs) in aqueous media

• degree of the agglomeration is mostly governed by the synthesis method, which defines their surface properties. During the synthesis processes or in subsequent process steps, the agglomeration of primary particles occurs as a result of the weak bonding between NPs. These primary aggregates then form

Metal hydrides: an innovative and challenging conversion reaction anode for lithium-ion batteries

• Luc Aymard,
• Yassine Oumellal and
• Jean-Pierre Bonnet

Beilstein J. Nanotechnol. 2015, 6, 1821–1839, doi:10.3762/bjnano.6.186

• actually x = 0.26Li. The particle size cannot be reduced below 0.1 μm through grinding, because immediate agglomeration of smaller particles occurs (Figure 12b,c). So, even if crystallite size of few nanometers can be reached during grinding, the formation of agglomerates of 5 to 30 μm (consisting of

• conductive additive and a coating agent, which prevents the agglomeration of the hydride particles during grinding. A detailed study of the effect of mechanical milling on the physical/chemical and electrochemical properties compared to AB5 alloys is available in [34]. Figure 15 shows the evolution of the

• [35][36]. Note that the C-free bonds created during the fracture of the graphene layer serve as oxygen scavengers, and their agglomeration and coating of the alloy particles enable a better chemical/physical protection against oxidation [34]. Based on the milling behavior of carbonaceous material [34

NanoE-Tox: New and in-depth database concerning ecotoxicity of nanomaterials

• Katre Juganson,
• Angela Ivask,
• Irina Blinova,
• Monika Mortimer and
• Anne Kahru

Beilstein J. Nanotechnol. 2015, 6, 1788–1804, doi:10.3762/bjnano.6.183

• ENMs generally include chemical composition, purity, primary particle size, shape, surface area, coating, agglomeration and/or aggregation, hydrodynamic size in the aqueous test medium, surface charge, stability and solubility of ENMs. For the current NanoE-Tox database (Supporting Information File 2

Template-controlled mineralization: Determining film granularity and structure by surface functionality patterns

• Nina J. Blumenstein,
• Jonathan Berson,
• Stefan Walheim,
• Petia Atanasova,
• Johannes Baier,
• Joachim Bill and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2015, 6, 1763–1768, doi:10.3762/bjnano.6.180

• these sites. The ZnO particles are attracted to these polar areas. Other particles are highly mobile due to the decreased interaction with the template. They can diffuse to the immobilized ones and decrease the interfacial energy by agglomeration. The result is a coarse granular structure that can be

Synthesis, characterization and in vitro biocompatibility study of Au/TMC/Fe₃O₄ nanocomposites as a promising, nontoxic system for biomedical applications

• Hanieh Shirazi,
• Maryam Daneshpour,
• Soheila Kashanian and
• Kobra Omidfar

Beilstein J. Nanotechnol. 2015, 6, 1677–1689, doi:10.3762/bjnano.6.170

• effect with respect to the exchange of TMC for chitosan: The TMC-coated nanoparticles exhibited a smaller diameter as compared to the chitosan-coated nanoparticles. No significant nanoparticle agglomeration was observed upon introduction of the polymers. The core–shell structure of the TMC/Fe3O4

In situ SU-8 silver nanocomposites

• Søren V. Fischer,
• Basil Uthuppu and
• Mogens H. Jakobsen

Beilstein J. Nanotechnol. 2015, 6, 1661–1665, doi:10.3762/bjnano.6.168

• homogeneously distributed silver nanoparticles in the photoresist matrix. No particle growth or agglomeration of nanoparticles is observed at this point. The reported new in situ silver nanocomposite materials can be spin coated as homogeneous thin films and structured by using UV lithography. A resolution of 5

• results in further AgNP formation in the composite and not particle growth or agglomeration. The plasmonic absorption maximum is close to 435 nm and is independent of the AgNO3 precursor concentration up to 125 mg·mL−1. The AgNPs formed in the SU-8 matrix is approximately 25 nm and distributed evenly in

How decision analysis can further nanoinformatics

• Matthew E. Bates,
• Sabrina Larkin,
• Jeffrey M. Keisler and
• Igor Linkov

Beilstein J. Nanotechnol. 2015, 6, 1594–1600, doi:10.3762/bjnano.6.162

• selected as it is well suited for the classification of nanomaterials with uncertain or unavailable physiochemical properties. Five extrinsic characteristics (agglomeration, reactivity, critical functional groups, particle size and contaminant dissociation) and three factors that are dependent on the

Influence of surface chemical properties on the toxicity of engineered zinc oxide nanoparticles to embryonic zebrafish

• Zitao Zhou,
• Jino Son,
• Bryan Harper,
• Zheng Zhou and
• Stacey Harper

Beilstein J. Nanotechnol. 2015, 6, 1568–1579, doi:10.3762/bjnano.6.160

• capping agents or surface ligands with differing chemical properties to functionalize the surface and improve stability against agglomeration and dispersibility in a given medium [16]. These surface alterations have the potential to alter their toxicity as a result of differences in the release of Zn2

• + ions and ROS production compared to bare ZnO NPs [17][18]. In addition, the behaviour of surface functionalized ZnO NPs may vary compared to non-functionalized (bare) ZnO NPs by altering stability and/or agglomeration, potentially altering bioavailability and toxicity to aquatic organisms [18][19][20

• ][21]. While the dissolution kinetics and agglomeration state of the ZnO NPs is known to influence the toxicity of the materials, this study aimed to determine if specific intrinsic features could be used in lieu of empirical data on the material’s behaviour. Surface chemical ligands and capping agents

Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

• Xiaoxing Ke,
• Carla Bittencourt and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2015, 6, 1541–1557, doi:10.3762/bjnano.6.158

• is presented in Figure 4a,b. Displaced carbon atoms may form adatoms (A) on the lattice. Atomistic computer simulations predict that the reconstruction of the atomic network near vacancies and adatoms is very likely to happen, resulting in an agglomeration of 5- to 8-membered rings [44][45]. As shown

Peptide-equipped tobacco mosaic virus templates for selective and controllable biomineral deposition

• Klara Altintoprak,
• Axel Seidenstücker,
• Alexander Welle,
• Sabine Eiben,
• Petia Atanasova,
• Nina Stitz,
• Alfred Plettl,
• Joachim Bill,
• Hartmut Gliemann,
• Holger Jeske,
• Dirk Rothenstein,
• Fania Geiger and
• Christina Wege

Beilstein J. Nanotechnol. 2015, 6, 1399–1412, doi:10.3762/bjnano.6.145

• peptides KD5 or KD10 showed continuous inorganic surface coatings on every single particle, with no significant agglomeration of the virus hybrids. Furthermore, deposition on these templates was highly specific; only a low amount of non-bound silica particles had formed (Figure 4b). The templates TMV–AH

• originally identified due to their ZnO binding properties (data not shown) [60]. The agglomeration and bundle formation we found for all three respective mineralized TMV templates might be due to their aggregation before the mineralization process, as it is known for histidine-presenting TMV particles [51

The Kirkendall effect and nanoscience: hollow nanospheres and nanotubes

• Abdel-Aziz El Mel,
• Ryusuke Nakamura and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2015, 6, 1348–1361, doi:10.3762/bjnano.6.139

• , vacancies are created and injected at the Co(core)/CoSe(shell) interface. The migration and agglomeration of vacancies result in the formation and merging of the initial voids located at the interface and extended along the Co core (Figure 4a). The increase in size of these voids was found to lead to the