Nanoparticle shapes by using Wulff constructions and first-principles calculations

• Georgios D. Barmparis,
• Zbigniew Lodziana,
• Nuria Lopez and
• Ioannis N. Remediakis

Beilstein J. Nanotechnol. 2015, 6, 361–368, doi:10.3762/bjnano.6.35

• . The quantity γhkl is the energy required to create a surface of unit area normal to the [hkl] vector, and is the analogous of the surface tension for liquids. This process is repeated for all sets of Miller indexes, (hkl). The space that lies inside all these planes defines the equilibrium shape for

• theorem is a generalization that considers lateral strain [14]. When the material under study is at equilibrium with another gas- or liquid-phase material, the interface tension, , is used in the Wulff construction instead of the surface tension, γhkl. The two are connected by a simple formula that

• , they have a much higher surface tension than low-index faces; (if a high-index surface and a low-index surface have equal surface tensions, the low-index will have a greater area as the high-index face will be steeper and will be hidden in the Wulff construction); does not take into account edge- and

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

• since ethanol has a lower liquid–vapor surface tension (γLV = 22 mJ·m−2) than water (γLV = 72 mJ·m−2), the higher the ethanol concentration in water, the lower the surface tension of the solution. Furthermore, the contact angle is generally proportional to the liquid surface tension by the Young’s

• relation where γSV and γSL are the solid–vapor and solid–liquid surface tensions, respectively. Therefore, also the contact angles of the carbon nanotube films decrease with the decrease in surface tension of the liquid droplet. This phenomenon is connected to the lipophilicity of the apolar surface of the

• respect to the MWCNT surface. Wetting states are studied changing the liquid surface tension by adding different ethanol concentrations in water. Wenzel regime (green solid line) fit reports a roughness factor r = 1.08 ± 0.01, while lipophilic (blue solid line) and hydrophobic (red solid line) Cassie

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

• area at a given indentation depth and A0 the surface area prior to indentation. Static equilibrium can be expressed by the Young–Laplace equation, which describes the pressure difference across the fluid interface as a function of surface tension T and mean curvature. The task is to determine the

The capillary adhesion technique: a versatile method for determining the liquid adhesion force and sample stiffness

• Daniel Gandyra,
• Stefan Walheim,
• Stanislav Gorb,
• Wilhelm Barthlott and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2015, 6, 11–18, doi:10.3762/bjnano.6.2

• is required, which consists of the surface energy of the meniscus plus the interface energy of the tip–water contact area minus the surface energy of the original flat air–water interface before formation of the capillary contact. Here, σ = 0.07275 N/m [25] is the surface tension of the liquid (here

Intake of silica nanoparticles by giant lipid vesicles: influence of particle size and thermodynamic membrane state

• Florian G. Strobl,
• Florian Seitz,
• Christoph Westerhausen,
• Armin Reller,
• Adriano A. Torrano,
• Christoph Bräuchle,
• Achim Wixforth and
• Matthias F. Schneider

Beilstein J. Nanotechnol. 2014, 5, 2468–2478, doi:10.3762/bjnano.5.256

• . Mechanical aspects of such a colloid–membrane interaction are treated by several theoretical models. A simple, purely mechanical picture of such an interaction involves at least three mechanical parameters: the adhesion energy per unit area gad, the bending stiffness of the membrane κ and its surface tension

• mJ/m2 (see below). This results in rcrit = 14 nm. Hence, the bending stiffness of the membrane should be considered for particles in the nano-regime. As soon as the membrane under observation exhibits a finite surface tension, its area compressibility modulus gten has to be considered as well, since

• consume a membrane patch with a surface area of Ap = 4πr2. If the vesicle volume would stay constant, the uptake of particles would stop at latest as soon as the surface tension of the vesicle σ exceeds the adhesion energy per unit area: Here, gten denotes the area compressibility modulus and ε the

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

• attachment mechanism of sessile aquatic animals and the aquatic realm presents many challenges to this mode of attachment. Viscous forces and the lack of surface tension under submerged conditions also affect frictional interactions in the aquatic environment. Moreover, the limitation of suction to the

• separates two hydrophilic surfaces in air. Pulling the surfaces apart will create a larger air–water boundary surface area. The surface tension of the liquid will resist to this increase and this is manifest as an adhesive force. According to [3] Laplace's law ought to be applied: The pressure difference

• (Δp) can be calculated from surface tension (γ), the overall radius of the liquid (ro) and the radius of the curved edge (re) (Figure 4). In contrast, under fully immersed conditions the surface tension should be zero, so that generally no capillary forces will occur under these conditions. This is an

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

• surface. The strong molecular interactions between graphene layers and DMF or NMP molecules, in addition to the fact that both solvents have a high boiling point and high surface tension, make their complete evaporation or removal very difficult. The presence of these residual molecules modifies the

Characterization of 10,12-pentacosadiynoic acid Langmuir–Blodgett monolayers and their use in metal–insulator–metal tunnel devices

• Saumya Sharma,
• Mohamad Khawaja,
• Manoj K. Ram,
• D. Yogi Goswami and
• Elias Stefanakos

Beilstein J. Nanotechnol. 2014, 5, 2240–2247, doi:10.3762/bjnano.5.233

• (PDA) and their use in metal–insulator–metal (MIM) devices were studied. The Langmuir monolayer behavior of the PDA film was studied at the air/water interface using surface tension–area isotherms of polymeric and monomeric PDA. Langmuir–Blodgett (LB, vertical deposition) and Langmuir–Schaefer (LS

• were characterized for suitability for small signal rectification in MIM tunnel diodes. The Langmuir monolayer behavior of PDA was studied at the air–water interface to find the ideal surface tension for a close-packed film at the water surface. This was followed by deposition of the film on silicon

• (>99.8%, Sigma-Aldrich). Figure 1 shows the molecular structure and UV-polymerized structure of the PDA molecule. The pH value of the water subphase was found to be 6.8. Surface tension–area isotherms were obtained using the KSV NIMA Langmuir–Blodgett Trough system for samples with varying volume and

Influence of stabilising agents and pH on the size of SnO₂ nanoparticles

• Olga Rac,
• Patrycja Suchorska-Woźniak,
• Marta Fiedot and
• Helena Teterycz

Beilstein J. Nanotechnol. 2014, 5, 2192–2201, doi:10.3762/bjnano.5.228

• with Sn4+ ions, and then the precipitated nanoparticles are surrounded by a polymer, resulting in a polymer matrix which is formed on its surface (Figure 5). To facilitate this process, the corresponding change in the surface tension by the addition of a surfactant in the solution is required. To

• showed that during the preparation of the tin dioxide nanoparticles (which result from the precipitation reaction), it is necessary to use both a polymer as well as a surfactant. This reduces the surface tension, making it easier to change the structure of the stabilising polymer chain. In addition, not

Properties of plasmonic arrays produced by pulsed-laser nanostructuring of thin Au films

• Katarzyna Grochowska,
• Katarzyna Siuzdak,
• Peter A. Atanasov,
• Carla Bittencourt,
• Anna Dikovska,
• Nikolay N. Nedyalkov and
• Gerard Śliwiński

Beilstein J. Nanotechnol. 2014, 5, 2102–2112, doi:10.3762/bjnano.5.219

• confirmed by investigation of the surface tension-driven flow leading to the Rayleigh–Taylor (R–T) instability. The R–T process has been concluded from coincidence between the droplet dimension (0.5 μm) obtained from the experiment and the model simulations, and with values of the Weber number as reported

• coalescence both result in the formation of the NP structure. The final geometry and NP distribution depends on the surface tension forces at equilibrium characterized by a minimal ratio of the NP surface-area-to-volume [31]. The short-range order observed for structures in Figure 1a–c confirms the NP self

• postulated how the NP shapes depend on the equilibrium of the surface tension forces [34]. The partially spherical/spheroidal shapes correspond to the case of partial wetting of the substrate by the molten metal and are characterized by a contact angle value of less than 90°. This angle approaches 180° in

Synthesis of Pt nanoparticles and their burrowing into Si due to synergistic effects of ion beam energy losses

• Pravin Kumar,
• Udai Bhan Singh,
• Kedar Mal,
• Sunil Ojha,
• Indra Sulania,
• Dinakar Kanjilal,
• Dinesh Singh and
• Vidya Nand Singh

Beilstein J. Nanotechnol. 2014, 5, 1864–1872, doi:10.3762/bjnano.5.197

• coupling. The melting of materials along the ion trajectory generates a surface tension gradient due to an imbalance of the surface and the interface energies, which further gives rise to mass transport through capillary action. The migration of metallic atoms and subsequent agglomeration can result in the

Surface topography and contact mechanics of dry and wet human skin

• Alexander E. Kovalev,
• Kirstin Dening,
• Bo N. J. Persson and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2014, 5, 1341–1348, doi:10.3762/bjnano.5.147

• regions covered by water is described by where γ is the surface tension of water. If ΔA is the surface area occupied by the capillary bridges then the attractive force is The contact area and the distribution of interfacial separations are determined by using the Persson contact mechanics model with the

Physical principles of fluid-mediated insect attachment - Shouldn’t insects slip?

• Jan-Henning Dirks

Beilstein J. Nanotechnol. 2014, 5, 1160–1166, doi:10.3762/bjnano.5.127

• , undeformable disk and substrate with a mediating continuous fluid-layer (see Figure 2 and [30][38][39][40][41][42]). In this simple model, the total adhesive force is basically the sum of three components: the surface tension of the fluid, the Laplace pressure (both often combined as “capillary forces”) and

• mediating fluid volume should decline over time. In a static adhesive pad with a Newtonian fluid, only the (negligible) surface tension and the small Laplace pressure would thus determine the overall adhesive force of the insect foot (Table 1). Fluid-mediated friction forces In a fluid mediated system with

• a continuous Newtonian fluid film, the friction forces between the substrates can in general be described by using two basic principles: the surface tension of the mediating fluid and the laws of hydrodynamic lubrication [55][56]. Surface tension The contribution of the surface tension of the

Nanoforging – Innovation in three-dimensional processing and shaping of nanoscaled structures

• Andreas Landefeld and
• Joachim Rösler

Beilstein J. Nanotechnol. 2014, 5, 1066–1070, doi:10.3762/bjnano.5.118

• also limited by the surface tension of the cast-material. Some complex three dimensional shapes were realized by casting of metal with a low melting temperature [3][4]. Dimensions of cast details are in the submillimeter- and microscale, and due to the mentioned limitations, applications in the

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

• section, a summary and an outlook are provided. Review 1 Contact angle and contact angle hysteresis with applied voltage When a voltage is applied to a droplet deposited on a solid surface, the surface tension between solid and liquid changes, which leads to a change of the wettability of the surface, the

• so called electrowetting [10][11][64][65]. The surface tension between solid and liquid decreases with increasing applied voltage, leading to a decrease of the CA. The change of the CA with the applied voltage V can be expressed by the Young–Lippmann equation [64][66] as: where θ0 is the original CA

• in the absence of an voltage, C is the capacitance of the dielectric layer, and γlv is the surface tension between liquid and vapor. In 1875, Lippmann found the electrowetting phenomenon and presented the Young–Lippmann equation, which is acknowledged as the basic of the electrowetting theory. In

Nanoscale particles in technological processes of beneficiation

• Sergey I. Popel,
• Vitaly V. Adushkin and
• Anatoly P. Golub'

Beilstein J. Nanotechnol. 2014, 5, 458–465, doi:10.3762/bjnano.5.53

• side of the vapor, and η and σ are the viscosity and surface tension of the liquid, respectively. The set of equations of gas-dynamics, which is solved together with the van der Waals equation of state describes the vapor motion as well as the pressure, the temperature, and the internal energy inside

Ni nanocrystals on HOPG(0001): A scanning tunnelling microscope study

• Michael Marz,
• Keisuke Sagisaka and
• Daisuke Fujita

Beilstein J. Nanotechnol. 2013, 4, 406–417, doi:10.3762/bjnano.4.48

• theory [27]), i.e., in the limit of small deformations. Thus, the adhesive force can be written as where γx is the surface tension and R the radius of the cluster, assuming a spherical particle. With γHOPG = 1.75 J/m2, γNi = 2.45 J/m2, and R = 5.9 nm, a pull off force of Fa = −4.36 nN is expected. The

Electrospinning preparation and electrical and biological properties of ferrocene/poly(vinylpyrrolidone) composite nanofibers

• Ji-Hong Chai and
• Qing-Sheng Wu

Beilstein J. Nanotechnol. 2013, 4, 189–197, doi:10.3762/bjnano.4.19

• morphologies of the fibers. It is considered that the viscosity and surface tension of the solution changes with increasing Fc content, which leads to this result [30][31]. The characterization of typical samples obtained was summarized in Table 1. In the experiment we found that when the amount of the Fc was

Direct monitoring of opto-mechanical switching of self-assembled monolayer films containing the azobenzene group

• Einat Tirosh,
• Enrico Benassi,
• Silvio Pipolo,
• Marcel Mayor,
• Michal Valášek,
• Veronica Frydman,
• Stefano Corni and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2011, 2, 834–844, doi:10.3762/bjnano.2.93

• molecular-level mechanical manipulators. As an example, macroscopic transport at the solid–liquid interface was driven by modifying the solid–liquid surface tension at a droplet front by using a molecular switch based on a SAM of rotaxane [8]. Central to the function of such systems are changes in the inter

Surface induced self-organization of comb-like macromolecules

• Konstantin I. Popov,
• Vladimir V. Palyulin,
• Martin Möller,
• Alexei R. Khokhlov and
• Igor I. Potemkin

Beilstein J. Nanotechnol. 2011, 2, 569–584, doi:10.3762/bjnano.2.61

• . The free energy was calculated by summation of the bending energy of the wormlike chain of the backbone, the Maier–Saupe contribution for LC ordering of side LC chains, the stretching energy of the amorphous block, the surface tension and the mixing Flory–Huggins contributions. Later studies [95][96

• of two different cylindrical and four different types of lamellar phases were found (Figure 3). Conditions for stability of each structure can be summarized as follows [96]: Amorphous cylinders: Long macromolecules; high fraction of the B and C (LC) units; any values of the surface tension

• coefficients satisfying the strong segregation conditions. Liquid crystalline cylinders: Long macromolecules; high fraction of the A units and small enough fraction of the liquid crystalline units; any values of the surface tension coefficients satisfying the strong segregation conditions. AB lamellae: Long

Dynamics of capillary infiltration of liquids into a highly aligned multi-walled carbon nanotube film

• Sławomir Boncel,
• Krzysztof Z. Walczak and
• Krzysztof K. K. Koziol

Beilstein J. Nanotechnol. 2011, 2, 311–317, doi:10.3762/bjnano.2.36

• understood [17]. The Hildebrand solubility parameter, expressed as a square root of cohesive energy density, can also be correlated with the surface tension (γL) [32], e.g., by the Equation 1 (where VL is molar volume of a liquid) [33][34]: However, a critical parameter for the flow of a liquid through

• law refers to a quasi-steady state of the liquid flow by the capillary action, where capillary force, expressed by the above thermodynamic parameters, contact angle (θ) and surface tension (γL), is compensated by gravity and viscous drag [35]. The height of the meniscus of the infiltrating liquid

• (penetration depth, radius of the channel) and variable parameters (surface tension and contact angle) (Equation 4): were H is the final height of the liquid in the capillary. The values of the surface tension for all infiltrating liquids are all within the same order of magnitude. The values of contact angle

Moisture harvesting and water transport through specialized micro-structures on the integument of lizards

• Philipp Comanns,
• Christian Effertz,
• Florian Hischen,
• Konrad Staudt,
• Wolfgang Böhme and
• Werner Baumgartner

Beilstein J. Nanotechnol. 2011, 2, 204–214, doi:10.3762/bjnano.2.24

• pressure, i.e., the atmospheric pressure plus the hydrostatic pressure acting on the liquid. γ is the surface tension, φ is the contact angle of the liquid on the unstructured capillary material, r is the radius of the capillary, η is the viscosity of the liquid, and ε is the coefficient of slip. The

Superhydrophobicity in perfection: the outstanding properties of the lotus leaf

• Hans J. Ensikat,
• Petra Ditsche-Kuru,
• Christoph Neinhuis and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2011, 2, 152–161, doi:10.3762/bjnano.2.19

• . Only the lotus leaves showed no significant loss of water repellency when water vapour condensed on the surface of the cooled samples at 5 °C. Wagner et al. (2003) [9] examined the morphology of the epidermal structures and the wettability with liquids of varying surface tension such as methanol–water

• drops touch only the highest papillae [12]. At higher pressures, e.g., at the impact of raindrops, the water intrudes deeper between the papillae (Figure 4a) and forms a meniscus at the still superhydrophobic wax tubules coating. The deformation of the non-wetting droplet surface due to surface tension

Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

• Bharat Bhushan

Beilstein J. Nanotechnol. 2011, 2, 66–84, doi:10.3762/bjnano.2.9

• ][43][44] and experimental studies [33][45][46][47] suggest that the presence of nanobubbles at the solid-liquid interface is responsible for boundary slip on hydrophobic surfaces. Roughness-induced superoleophobicity The surface tension of oil and organic liquids is lower than that of water, so to

• et al. [54] showed that surface curvature, in conjunction with chemical composition and roughened texture, can be used for liquids with low surface tension, including alkanes such as decane and octane. Liu et al. [18] performed experiments in a solid-water-oil interface. They found that hydrophilic

• hydrophilic surface (γSA > γSW), an oleophobic surface in the solid–water–oil interface can be created if γOA·cos θO is lower than γWA·cos θW. Since the surface tension of oil and organic liquids is much lower than that of water, most hydrophilic surfaces can be made oleophobic in a solid–water–oil interface