Growth behaviour and mechanical properties of PLL/HA multilayer films studied by AFM

• Cagri Üzüm,
• Johannes Hellwig,
• Narayanan Madaboosi,
• Dmitry Volodkin and
• Regine von Klitzing

Beilstein J. Nanotechnol. 2012, 3, 778–788, doi:10.3762/bjnano.3.87

• the film bilayer number n. This result contradicts the results of Richert et al. [4], who reported a decrease in E from 90 kPa for n = 20 to 40 kPa for n = 60. The authors suggested a possibility of film softening due to greater hydration of the upper layers rather than due to a change in surface

• structure, heterogeneity or roughness. The film thickness range reported in the mentioned study [4] is nearly threefold larger than ours, which may result in significant structural differences. Despite some fluctuations, E in our study ranges between 10 and 40 kPa, being in the same order of magnitude with

Macromolecular shape and interactions in layer-by-layer assemblies within cylindrical nanopores

• Thomas D. Lazzara,
• K. H. Aaron Lau,
• Wolfgang Knoll,
• Andreas Janshoff and
• Claudia Steinem

Beilstein J. Nanotechnol. 2012, 3, 475–484, doi:10.3762/bjnano.3.54

• adsorbing components, to generate multilayered structures. Different functional materials can be stepwise incorporated by LbL, within a single surface structure by electrostatic self-assembly [3][4], molecular-recognition pairs [5][6][7], or covalent-bond formation [8]. Homogeneous and heterogeneous layered

Repulsive bimodal atomic force microscopy on polymers

• Alexander M. Gigler,
• Christian Dietz,
• Maximilian Baumann,
• Nicolás F. Martinez,
• Ricardo García and
• Robert W. Stark

Beilstein J. Nanotechnol. 2012, 3, 456–463, doi:10.3762/bjnano.3.52

• between both types of polymers, which differ considerably in stiffness. However, if the amplitude of the additional oscillation becomes too large, the bimodal technique may become destructive to the surface structure, counteracting a good phase contrast. Figure 5 shows an SB sample measured in the

The morphology of silver nanoparticles prepared by enzyme-induced reduction

• Henrik Schneidewind,
• Thomas Schüler,
• Katharina K. Strelau,
• Karina Weber,
• Dana Cialla,
• Marco Diegel,
• Roland Mattheis,
• Andreas Berger,
• Robert Möller and
• Jürgen Popp

Beilstein J. Nanotechnol. 2012, 3, 404–414, doi:10.3762/bjnano.3.47

• silver nanoparticles consist of single-crystalline plates of pure silver. The surface-enhanced Raman spectroscopic (SERS) activity of the EGNP structures is promising due to the exceptionally rough surface structure of the silver nanoparticles. SERS measurements of the vitamin riboflavin incubated on the

Modeling noncontact atomic force microscopy resolution on corrugated surfaces

• Kristen M. Burson,
• Mahito Yamamoto and
• William G. Cullen

Beilstein J. Nanotechnol. 2012, 3, 230–237, doi:10.3762/bjnano.3.26

• -supported graphene, due to apparent differences in surface structure between the carefully UHV-prepared quartz in that study and the SiO2 substrates used for graphene. As with the barium silicate measurements, for high-resolution measurements of SiO2, special conditions were necessary [18]. In order to

Noncontact atomic force microscopy study of the spinel MgAl₂O₄(111) surface

• Morten K. Rasmussen,
• Kristoffer Meinander,
• Flemming Besenbacher and
• Jeppe V. Lauritsen

Beilstein J. Nanotechnol. 2012, 3, 192–197, doi:10.3762/bjnano.3.21

• and in particular a direct atomic-scale characterization of the surface structure is largely missing for a range of important metal oxides. In recent years, the noncontact atomic force microscope (NC-AFM) has been established as a unique tool to provide atomic-resolution real-space images of all types

• atomic scale of this important group of materials. In this work, a new surface-structure model of the MgAl2O4(111) surface, based on experimental NC-AFM data obtained on this surface, prepared under well-controlled ultrahigh vacuum (UHV) conditions, is presented. MgAl2O4 is a prototypical material with

• available concerning the surface structure. According to a theoretical study by Harding et al., and other theoretical studies [15][16][17], the oxygen-terminated MgAl2O4(111) is evaluated to be in its lowest energy state with 42% of the oxygen atoms removed from the oxygen crystal plane to fulfill the

Quantitative multichannel NC-AFM data analysis of graphene growth on SiC(0001)

• Christian Held,
• Thomas Seyller and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2012, 3, 179–185, doi:10.3762/bjnano.3.19

• , the surface structure remains the same upon oxide removal (Figure 2b). The width of the large terraces is slightly reduced and a number of smaller and larger pits and islands with lateral extensions of only a few nanometers up to hundreds of nanometers are found. Except for a few remaining rough spots

• change in contact potential (Figure 3b). The underlying surface structure is analyzed in Figure 3c and represented in an atomic ball-and-stick scheme in Figure 3d. The left step is a substrate step of three bilayers of SiC with a height of 0.75 nm, indicated by the three blue blocks representing the

• graphene spots are regularly observed to grow over a SiC bilayer substrate step. No change in contact potential is observed without a corresponding change in step height. The much simpler surface structure of samples prepared in an argon atmosphere is demonstrated in Figure 4b. The identification of

qPlus magnetic force microscopy in frequency-modulation mode with millihertz resolution

• Maximilian Schneiderbauer,
• Daniel Wastl and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2012, 3, 174–178, doi:10.3762/bjnano.3.18

• -polarized tip and the spin-dependent local density of states of the sample (Figure 1b). STM is unable to probe insulating surfaces but AFM can be used: The antiferromagnetic surface structure of NiO (001) was imaged by Magnetic Exchange Force Microscopy (MExFM) [5]. In MExFM the magnetic exchange force

• systems [19] and low-temperature systems [12][20][21]. For this sensor setup, see inset in Figure 3a, we found an amplitude of 25 nm in both paths and a lift height of 35 nm to be a good choice. The first-pass topography data set shows the expected surface structure (Figure 3a). The scan speed again had

Effect of the tip state during qPlus noncontact atomic force microscopy of Si(100) at 5 K: Probing the probe

• Adam Sweetman,
• Sam Jarvis,
• Rosanna Danza and
• Philip Moriarty

Beilstein J. Nanotechnol. 2012, 3, 25–32, doi:10.3762/bjnano.3.3

• -prepared tips and surfaces, however, a wide range of imaging interactions are often observed, resulting in varying apparent topographic structures [5][6][7]. In cases where there has been debate as to the surface structure (for example TiO2 [8] and Si(100) [9]) different imaging mechanisms can result in

Approaches to nanostructure control and functionalizations of polymer@silica hybrid nanograss generated by biomimetic silica mineralization on a self-assembled polyamine layer

• Jian-Jun Yuan and
• Ren-Hua Jin

Beilstein J. Nanotechnol. 2011, 2, 760–773, doi:10.3762/bjnano.2.84

• -driven self-assembly of preformed PSS-wrapped CNTs. In our case, the presence of IPA in the media was assumed to play an essential role in the formation of the pyramidlike structure since the use of neat water did not give this kind of surface structure. However, the detailed formation mechanism is still

• (Figure 2f). There was no aggregation of nanoribbon heads on the film surface. TEM images indicate that this nanograss is composed of well-defined nanoribbons with a typical width of about 50 nm and a very smooth surface structure (Figure 3c and d). Cross-sectional observation showed a nanograss thickness

• silica source. However, the TEM study illustrates the obvious difference in the surface structure of the ribbon film. The ribbons from TMOS source show a particulatelike and rough surface (Figure 3e and 3f), whereas the use of MS51 as the source led to ribbons with a very smooth surface (Figure 3d). This

The effect of surface anisotropy in the slippery zone of Nepenthes alata pitchers on beetle attachment

• Elena V. Gorb and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2011, 2, 302–310, doi:10.3762/bjnano.2.35

• given in Figure 2. These cells are responsible for the anisotropic surface relief of up to 10 μm in height, whereas crystalline wax coverage creates an additional roughness in the range of about 1 µm. De-waxed pitcher samples and their polymer replicas displayed a very similar surface structure with a

Sorting of droplets by migration on structured surfaces

• Wilfried Konrad and
• Anita Roth-Nebelsick

Beilstein J. Nanotechnol. 2011, 2, 215–221, doi:10.3762/bjnano.2.25

• . In our approach, it is essentially the surface structure which is varied, not the contact angle. It may be speculated that suitably patterned surfaces are also utilised in biological surfaces where a large variety of ornamentations and surface structuring are often observed. Keywords: microdroplets

• droplet diameter. In our approach, it is essentially the surface structure which is varied, not the contact angle. The actual movement of the droplet on the continuously varying solid surface pattern depends both on the surface pattern and on the contact angle between droplet and solid. Therefore, it is

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

• , these replicas have a good resemblance to the surface structure (see Supporting Information File 4). As expected, the replicas did not exhibit an improved wetting behaviour if they were dried before the experiment. Under these conditions the contact angle is almost identical to the contact angle of the

• were recorded with a frame rate of 18 frames per second. Even in the first frame after contact, thus at about 50 ms after the droplet contacts the surface, the droplet is mostly spread and within 2 s the water is completely spread on the surface structure. Scale of Phrynosoma cornutum dipped into

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

• structure consisting of papillae with a dense coating of agglomerated wax tubules, which is the basis for the famous superhydrophobicity (Figure 1). However, a hierarchical surface structure which induces strong water repellency and contact angles above 150° is not a special feature of lotus leaves. It has

• regenerate damaged or lost waxes. Conclusion It is true that lotus exhibits outstanding water repellency on the upper side of its leaves. The basis of this behaviour is the hierarchical surface structure. In comparison to other species with a hierarchical surface structure composed of papillae and wax

• (SEM) image of the upper leaf side prepared by ‘glycerol substitution’ shows the hierarchical surface structure consisting of papillae, wax clusters and wax tubules. (c) Wax tubules on the upper leaf side. (d) Upper leaf side after critical-point (CP) drying. The wax tubules are dissolved, thus the

Capillary origami: superhydrophobic ribbon surfaces and liquid marbles

• Glen McHale,
• Michael I. Newton,
• Neil J. Shirtcliffe and
• Nicasio R. Geraldi

Beilstein J. Nanotechnol. 2011, 2, 145–151, doi:10.3762/bjnano.2.18

• origami or droplet wrapping. In this work, we consider how the conditions for the spontaneous, capillary induced, folding of a thin ribbon substrate might be altered by a rigid surface structure that, for a rigid substrate, would be expected to create Cassie–Baxter and Wenzel effects. For smooth thin

• consideration to ribbon-type substrates and disconnected solid grains with a rigid surface structure. We review the case for surface roughness that has low aspect ratio so that the liquid can penetrate into the structure – the Wenzel case [14][15]. We then consider whether droplet wrapping can occur without

• penetration into the surface structure – the Cassie–Baxter case [16][17]. We show that droplet wrapping should occur with both types of configuration and we derive a condition for the transition between these two cases; this condition is the same as for the Wenzel to Cassie–Baxter transition on a

Superhydrophobic surfaces of the water bug Notonecta glauca: a model for friction reduction and air retention

• Petra Ditsche-Kuru,
• Erik S. Schneider,
• Jan-Erik Melskotte,
• Martin Brede,
• Alfred Leder and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2011, 2, 137–144, doi:10.3762/bjnano.2.17

• gaps (underside of elytra) or even vanished completely after a few days (sternites). Moreover, the upper side of the elytra was able to keep an air film up to flow velocities of 5 m/s. Obviously the complex surface structure with tiny dense microtrichia and two types of larger specially shaped setae is

• ? (2) Is there a correlation between surface structure and air film persistence? (3) How is it possible to hold the air film under hydrodynamic conditions? (4) How much is the friction on the elytron surface reduced? Results and Discussion Characteristics of air retaining surfaces Notonecta glauca is

• surfaces in order to exclude an influence of a possibly different surface chemistry. The results show similar air film persistence on untreated and treated surfaces (Table 3). Consequently, the surface structure can be identified as the relevant feature. The air covering the surfaces can be identified by

Schottky junction/ohmic contact behavior of a nanoporous TiO₂ thin film photoanode in contact with redox electrolyte solutions

• Masao Kaneko,
• Hirohito Ueno and
• Junichi Nemoto

Beilstein J. Nanotechnol. 2011, 2, 127–134, doi:10.3762/bjnano.2.15

• surface structure by ligand exchange of the Fe2+/3+ center between CN− and Ti–O−. When both the methanol and the [Fe(CN)6]4− were present in the aqueous phase, the behavior was interesting. In the dark, the CV also showed clear reversible redox waves for the [Fe(CN)6]4−/3− couple (Figure 7) at 0.26 V vs

Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

• Bharat Bhushan

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

• 5°, respectively. As shown in Figure 11 and Table 3, it is observed that both surfaces are oleophilic in solid–water–oil interface. To study the surface structure of an aquatic animal, experiments with water and oil droplets on the shark skin replica were performed in a three phase interface [20

Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

• Thomas König,
• Georg H. Simon,
• Lars Heinke,
• Leonid Lichtenstein and
• Markus Heyde

Beilstein J. Nanotechnol. 2011, 2, 1–14, doi:10.3762/bjnano.2.1

• height that is 10 pm lower than the average height of corresponding terrace sites (see Figure 11b). Knowing the surface structure with highest accuracy, it is still very desirable to determine aspects of electronic structures to gain further insight. In Figure 12, the effective contact potential is

• defect-free MgO. The NC-AFM investigation on aluminum oxide on NiAl(110) unveils the surface structure of the domain and at the APDBs with atomic resolution. Apart from the determined topography, F2+-like centers, which have been predicted by DFT calculations, were experimentally verified for the APDBs

The description of friction of silicon MEMS with surface roughness: virtues and limitations of a stochastic Prandtl–Tomlinson model and the simulation of vibration-induced friction reduction

• W. Merlijn van Spengen,
• Viviane Turq and
• Joost W. M. Frenken

Beilstein J. Nanotechnol. 2010, 1, 163–171, doi:10.3762/bjnano.1.20

• micronscale. This surface structure is formed by the 2-step RIE (Reactive Ion Etching) process used for etching the structures from an initially continuous polycrystalline silicon film. These surface features are consistently there, from die to die, and from run to run, although they are, of course, also

A collisional model for AFM manipulation of rigid nanoparticles

• Enrico Gnecco

Beilstein J. Nanotechnol. 2010, 1, 158–162, doi:10.3762/bjnano.1.19

• which is determined by several factors such as the scan pattern, the surface structure and the geometry of both tip and particle. Predicting the direction of motion of nanoparticles is very important, especially if it is desired to manipulate several particles at the same time. Here, we show that this

Sensing surface PEGylation with microcantilevers

• Natalija Backmann,
• Natascha Kappeler,
• Thomas Braun,
• François Huber,
• Hans-Peter Lang,
• Christoph Gerber and
• Roderick Y. H. Lim

Beilstein J. Nanotechnol. 2010, 1, 3–13, doi:10.3762/bjnano.1.2

• surface structure (Figure 6). In contrast, the Au surface topography does not change regardless of the scanning force used in 20% 2-propanol (poor solvent). This is due to the collapsed conformation of tethered PEG chains that offers minimal resistance against the AFM tip. The influence of solvent quality