Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions

• Robert Kozioł,
• Marcin Łapiński,
• Paweł Syty,
• Damian Koszelow,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2020, 11, 494–507, doi:10.3762/bjnano.11.40

• type of dewetting [19][20][21]. If dewetting is of the spinodal type, then the above parameters are related in the following way: where f(θ) is a geometric factor based on the particle contact angle θ, γ is the surface tension of the metal and A is the Hamaker constant. This is valid for the

An investigation on the drag reduction performance of bioinspired pipeline surfaces with transverse microgrooves

• Weili Liu,
• Hongjian Ni,
• Peng Wang and
• Yi Zhou

Beilstein J. Nanotechnol. 2020, 11, 24–40, doi:10.3762/bjnano.11.3

• viscous drag was mainly caused by the above effects. (2) Wettability: Jung and co-workers [41] found through experiments that microstructures with a higher contact angle provided a higher reduction of pressure drop in both laminar and turbulent water flows. Since surface wettability had a significant

• influence on the turbulent flow drag, the contact angle of the experimental specimen was measured by the sessile drop method to investigate the impact of the microgrooves on the wettability of the pipeline surface. As shown in Figure 20, the contact angles were 68 and 99° on the smooth and the microgrooved

• surface. In this case, the hydrophobicity of the pipeline surface was improved by the transverse microgrooves. The better the hydrophobicity of the surface was, the lower the adhesion of water was. Therefore, the increased contact angle of the bionic pipeline was beneficial for reducing the drag

Multiwalled carbon nanotube based aromatic volatile organic compound sensor: sensitivity enhancement through 1-hexadecanethiol functionalisation

• Nadra Bohli,
• Meryem Belkilani,
• Juan Casanova-Chafer,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2019, 10, 2364–2373, doi:10.3762/bjnano.10.227

• spectroscopy, X-ray photoelectron spectroscopy (XPS) and contact angle measurements. In summary, the obtained FTIR results confirm the covalent functionalisation of Au-decorated MWCNTs with HDT. Sensing results Au-MWCNT sensing of aromatic VOCs Figure 4 shows the response of the Au-MWCNT sensor to benzene and

• the sensor response was studied in a previous work [32]. The response to vapours remains basically unchanged for sensors employing hydrophobic thiols due to their hydrophobicity [31]. Such long-chain alkanethiol functionalised and decorated MWCNTs showed a high contact angle with water, which remains

The importance of design in nanoarchitectonics: multifractality in MACE silicon nanowires

• Stefania Carapezzi and
• Anna Cavallini

Beilstein J. Nanotechnol. 2019, 10, 2094–2102, doi:10.3762/bjnano.10.204

• force FC between two cylindrical pillars when partially immersed in a liquid is [29] where γliq is the liquid surface tension, θ is the contact angle between the liquid and the surface of the pillar, r is the radius of the pillar and 2x is the interdistance between the axes of the two pillars (see

Ion mobility and material transport on KBr in air as a function of the relative humidity

• Dominik J. Kirpal,
• Korbinian Pürckhauer,
• Alfred J. Weymouth and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2019, 10, 2084–2093, doi:10.3762/bjnano.10.203

• small and sharp splinter of a smashed sapphire bulk crystal was used as a tip. Sapphire is a very hard material, it is hydrophobic with a contact angle to water above 80°[20], and it is chemically inert [21]. The high hardness allows us to create large artificial defects in our sample (as described

Nanostructured and oriented metal–organic framework films enabling extreme surface wetting properties

• Andre Mähringer,
• Julian M. Rotter and
• Dana D. Medina

Beilstein J. Nanotechnol. 2019, 10, 1994–2003, doi:10.3762/bjnano.10.196

• were synthesized as highly crystalline bulk materials. The M-CAT-1 surface energy was estimated by contact angle measurements using pellet samples exposing nonoriented crystallites on the surface. Next, oriented and compact Co- and Ni-CAT-1 films were deposited on gold surfaces by vapor-assisted

• activated MOF, roughness (RMS): 37 nm). Scanning electron microscope (SEM) micrographs reveal densely packed and randomly oriented MOF crystallites throughout the sample (see Figure S3.2, Supporting Information File 1). For the contact angle (CA) measurements at the solid/air interface we chose

• chlorinated oils such as dichloromethane on M-CAT-1 pellets (see Figure S3.3, Supporting Information File 1). This further illustrates the amphiphilic nature of the M-CATs, showing hydrophilic as well as superoleophilic behavior towards several different oils. Interestingly, the underwater oil contact angle

Upcycling of polyurethane waste by mechanochemistry: synthesis of N-doped porous carbon materials for supercapacitor applications

• Christina Schneidermann,
• Pascal Otto,
• Desirée Leistenschneider,
• Sven Grätz,
• Claudia Eßbach and
• Lars Borchardt

Beilstein J. Nanotechnol. 2019, 10, 1618–1627, doi:10.3762/bjnano.10.157

• materials has been confirmed by using the dynamic contact angle technique (Figure S7, Supporting Information File 1). As expected, the samples absorbed the water droplet almost immediately after its release. The sample PUUPC-800-2 absorbed the water droplet completely after only 8 s, whereas sample PUPC-800

Rapid, ultraviolet-induced, reversibly switchable wettability of superhydrophobic/superhydrophilic surfaces

• Yunlu Pan,
• Wenting Kong,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2019, 10, 866–873, doi:10.3762/bjnano.10.87

• switching and extreme wettability changes upon ultraviolet (UV) illumination were investigated. TiO2 nanoparticles were modified in solutions of trimethoxy(alkyl)silane, and the suspensions were sprayed on glass substrates. For such samples, the water contact angle (WCA) was shown to transition from a

• surfaces exhibiting reversible wettability [20]. Wang et al. [21] prepared a TiO2 polycrystalline film which achieved drastic changes in wettability when the water contact angle (WCA) was changed from 72° and 0° under UV illumination, followed by recovery at around 70° after storing in the dark. Jin et al

• spectroscopy (FTIR, Nicolet iS50, Thermo Scientific, USA). The contact angles were measured at room temperature with an optical contact angle meter (DropMeterTM Element A-60, Maist, Ningbo, China), where the static CAs of the droplets (6 µL) placed onto the surfaces were measured five times at different

Novel reversibly switchable wettability of superhydrophobic–superhydrophilic surfaces induced by charge injection and heating

• Xiangdong Ye,
• Junwen Hou and
• Dongbao Cai

Beilstein J. Nanotechnol. 2019, 10, 840–847, doi:10.3762/bjnano.10.84

• ], temperature [12][13][14][15], pH [16][17][18], and electric field [19][20][21][22][23][24][25] stimulation. Zhang et al. [4] reported that superhydrophobic titanium dioxide surfaces become hydrophilic with a contact angle of 0° after 240 min of ultraviolet radiation. Nishimoto et al. [5] developed a method

• ] deposited thin films of titanium dioxide nanorods on glass substrates by a low-temperature hydrothermal method. The films were stored in the dark for two weeks to yield films with a contact angle of 154 ± 1.3°. Film irradiation with ultraviolet light for 2 h rendered the films superhydrophilic with a

• contact angle of 0°. Li et al. [8] prepared a superhydrophobic and superhydrophilic zinc oxide film on a bamboo surface. The surface was irradiated by ultraviolet radiation/darkroom for 12 h. A storage period of ten days induced the reversible switching between superhydrophilicity and superhydrophobicity

Self-assembly and wetting properties of gold nanorod–CTAB molecules on HOPG

• Imtiaz Ahmad,
• Floor Derkink,
• Tim Boulogne,
• Pantelis Bampoulis,
• Harold J. W. Zandvliet,
• Hidayat Ullah Khan,
• Rahim Jan and
• E. Stefan Kooij

Beilstein J. Nanotechnol. 2019, 10, 696–705, doi:10.3762/bjnano.10.69

• nonwetting substrates, suspension droplets typically leave a deposit of particles after evaporation of the solvent in the form of a cluster [54][55][56]. For instance, to maintain its contact angle on nonwetting surface like HOPG, the inward motion of the shrinking droplet will sweep away all particles from

Ultrathin hydrophobic films based on the metal organic framework UiO-66-COOH(Zr)

• Miguel A. Andrés,
• Clemence Sicard,
• Christian Serre,
• Olivier Roubeau and
• Ignacio Gascón

Beilstein J. Nanotechnol. 2019, 10, 654–665, doi:10.3762/bjnano.10.65

• /surfactant films containing 10 wt % octadecylphoshonic acid (ODP) have been deposited on substrates of different nature by Langmuir–Blodgett (LB) and Langmuir–Schaefer (LS) methods, showing that the presence of even only one MOF/ODP monolayer can increase the water contact angle of highly hydrophilic

• ) and water contact angle (WCA) measurements. The results obtained demonstrate the hydrophobic character of the films obtained, since a single mixed ODP/MOF LB film can increase the water contact angle of highly hydrophilic substrates (glass and mica) up to 120° while maintaining a high transparency

• of LB films were higher due to the low deposition of MOF (2 µg for the LB film and ≈6 µg for the drop-cast sample). Ultrathin hydrophobic coatings To study the hydrophobic character of LB, LS and RLS films, water contact angle (WCA) values were measured on glass and mica substrates before and after

Topochemical engineering of composite hybrid fibers using layered double hydroxides and abietic acid

• Liji Sobhana,
• Lokesh Kesavan,
• Jan Gustafsson and
• Pedro Fardim

Beilstein J. Nanotechnol. 2019, 10, 589–605, doi:10.3762/bjnano.10.60

• purity, bonding, and morphology. These fibers further were tested for water contact angle (hydrophobicity), oil absorption (lipophilicity), tensile strength and ISO brightness measurements. The performance of C-HF was compared with unmodified reference fibers (REF), fibers composed with only AA (C-F) and

• our earlier reported work. Those methods are 1) pulp disintegration, 2) LDH preparation in the presence of pulp fibers, 3) water contact angle measurements, 4) oil absorption measurements, 5) tensile strength measurements, 6) fiber handsheet making. The remainder of the protocols are reported here for

• characterization of fiber surfaces. The samples were coated with carbon in a Temcarb TB500 sputter coater (Emscope Laboratories, Ashford, UK), the optimum accelerating voltage was 2.70 kV. Material testing Water contact angle measurements The hydrophobicity of reference and modified cellulose handsheets was

Hydrophilicity and carbon chain length effects on the gas sensing properties of chemoresistive, self-assembled monolayer carbon nanotube sensors

• Juan Casanova-Cháfer,
• Carla Bittencourt and
• Eduard Llobet

Beilstein J. Nanotechnol. 2019, 10, 565–577, doi:10.3762/bjnano.10.58

• (which accounted for 5.7 wt % in bare samples) is almost no longer “visible” by XPS after the formation of the SAM. The hydrophilicity of the different coatings was studied via contact angle measurements. It was found that bare Au-MWCNTs showed a hydrophilic character due to the presence of carboxyl

• XPS technique. Contact angle measurements. Sensor fabrication process detailed. Alumina heater description and sensor wire-bonded to a PCB. Supporting Information File 106: Figures related to thiol-Au-carbon nanotubes and experimental data obtained during the material characterization

Biocompatible organic–inorganic hybrid materials based on nucleobases and titanium developed by molecular layer deposition

• Leva Momtazi,
• Henrik H. Sønsteby and
• Ola Nilsen

Beilstein J. Nanotechnol. 2019, 10, 399–411, doi:10.3762/bjnano.10.39

• unaffected by exposure to air. The wettability of the surfaces was investigated by measuring the contact angle of water for different films using a goniometer. The contact angle was measured on three different spots for each sample. Each spot was measured 10 times in steps of adding 2 µL of water. All three

• and Ti-L-aspartic acid films where a contact angle of approximately 30° was measured on the surface of these materials in our previous study [22]. The growth dynamics of the individual systems were further investigated by adding an extra water pulse after the organic precursor to shed light on the

• purging system. An uncoated Si(100) substrate was used to collect the background. Atomic force microscopy (AFM) measurements were performed in contact mode using a Park XE70 device. The data were analyzed using the Gwyddion 2.44 SPM visualization tool. The contact angle measurements were performed using a

Development of an anti-pollution coating process technology for the application of an on-site PV module

• Sejin Jung,
• Wonseok Choi,
• Jung Hyun Kim and
• Jang Myoun Ko

Beilstein J. Nanotechnol. 2019, 10, 332–336, doi:10.3762/bjnano.10.32

• using different periods of time. For the fabricated specimens, the contact angle, anti-pollution characteristics, hardness, and adhesion were measured. The process conditions were optimized by analyzing the measurement results. Experimental The coating solution that was used to improve the anti

• angles of the fabricated functional coating films were measured using a contact angle analyzer (Phoenix 300 Touch, S.E.O. Co., South Korea). The anti-pollution characteristics were measured using permanent markers instead of actual pollutants. This method is useful for checking the level of pollutant

• . The light transmittance increased for the first three times of torch annealing. After the fourth and fifth treatment the transmittance was similar to that after the third annealing. Figure 2 and Figure 3 show the contact angle characteristics according to the annealing treatment method. The contact

A comparison of tarsal morphology and traction force in the two burying beetles Nicrophorus nepalensis and Nicrophorus vespilloides (Coleoptera, Silphidae)

• Liesa Schnee,
• Benjamin Sampalla,
• Josef K. Müller and
• Oliver Betz

Beilstein J. Nanotechnol. 2019, 10, 47–61, doi:10.3762/bjnano.10.5

• in N. vespilloides. The body-size-corrected numbers are almost identical in both species. Surface roughness and contact angle measurements The contact angles (CA) of static droplets of doubly distilled water on the epoxy casts (10 surfaces for each combination) were about 40° on the hydrophilic

• Stork [8]. For each species, four males and four females were examined. The diameters of some claw tips were also measured to gain further information on the effect of the claws. Preparation of test surfaces and contact angle measurements Traction-force experiments In order to investigate the effect of

• s in Antispread E2 (E2/200 Fluorocarbon 60, Horb-Ahldorf, Germany) solution and air-dried for 24 h at room temperature, a method used previously [14][55]. All treated surfaces were controlled by means of static contact angle measurements by using five 4 µL droplets of doubly distilled water. Images

Femtosecond laser-assisted fabrication of chalcopyrite micro-concentrator photovoltaics

• Franziska Ringleb,
• Stefan Andree,
• Berit Heidmann,
• Jörn Bonse,
• Katharina Eylers,
• Owen Ernst,
• Torsten Boeck,
• Martina Schmid and
• Jörg Krüger

Beilstein J. Nanotechnol. 2018, 9, 3025–3038, doi:10.3762/bjnano.9.281

• islands and the associated contact angle were significantly influenced by the temperature during PVD. At higher temperatures the islands became flatter, probably due to the decrease in surface tension of the liquid indium. The deposition rate of indium, however, had little influence on the contact angle

In situ characterization of nanoscale contaminations adsorbed in air using atomic force microscopy

• Jesús S. Lacasa,
• Lisa Almonte and
• Jaime Colchero

Beilstein J. Nanotechnol. 2018, 9, 2925–2935, doi:10.3762/bjnano.9.271

• [31] and the RCA process [32], both of which are very successful in the removal of organic and metal contamination. Several methods for tip characterization have been proposed, such as X-ray analysis, Raman spectroscopy, contact angle measurements, and scanning and transmission electron microscopy [33

• 50 nm diameter and 10–20 nm height (contact angle of these drop-like particles assuming a spherical surface: about 45°). From this topographic image we deduce that the surface of the cantilever is severely contaminated. Moreover, as observed in Figure 1c, essentially the same kind of contamination is

• the contact angle of the (nano-)meniscus within the tip–sample system. Usually, the system “wets”, then cos(φ) ≈ 1). In our experiments we have observed with an optical microscope how the probe-tip jumps into contact with the sample-tip. Then, the whole probe system, i.e., the mesoscopic cantilever

Controlling surface morphology and sensitivity of granular and porous silver films for surface-enhanced Raman scattering, SERS

• Sherif Okeil and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 2813–2831, doi:10.3762/bjnano.9.263

• microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron (XPS and Auger) and ultraviolet–visible spectroscopy (UV–vis) as well as contact angle measurements. It was found that different morphologies of the roughened Ag films could be obtained under controlled

• Scientific UV–vis spectrophotometer (Evolution 600). The water contact angle was measured using a Krüss DSA 30 model drop-shape analysis system. The water contact angle was measured by placing 5 µL water droplets on the silver surface. Atomic layer deposition (ALD) of Al2O3 Silver films on glass substrates

• contact angle measurements of the plasma treated silver films (Figure 10). A change in surface wettability was obtained after the different plasma treatments. Obviously all rf plasma treatments lead to better wettabilities (water contact angles between 44.7° ± 0.11° and 106.6° ± 0.53°) when compared to

Biomimetic surface structures in steel fabricated with femtosecond laser pulses: influence of laser rescanning on morphology and wettability

• Camilo Florian Baron,
• Alexandros Mimidis,
• Daniel Puerto,
• Evangelos Skoulas,
• Emmanuel Stratakis,
• Javier Solis and
• Jan Siegel

Beilstein J. Nanotechnol. 2018, 9, 2802–2812, doi:10.3762/bjnano.9.262

• for mimicking this structure by exploiting self-organization mechanisms. In particular, employing a combination of such isotropic microstructures shown in Figure 2B (which determine the water contact angle, as will be shown in Figure 4) with an anisotropic overstructure with dimensions of hundreds of

• rough surfaces, an important question is whether the liquid on top completely fills up the roughness grooves (homogeneous wetting regime) or leaves air inclusions entrapped inside the grooves (homogeneous wetting regime), which strongly affects the apparent contact angle [44][45]. For these two regimes

• dependence of surface wetting on surface energy and topography makes it particularly difficult to predict the wetting scenario, knowledge of the apparent contact angle alone is often sufficient for practical applications. For the particular case of steel, it is known that the laser-processed material evolves

Low cost tips for tip-enhanced Raman spectroscopy fabricated by two-step electrochemical etching of 125 µm diameter gold wires

• Antonino Foti,
• Francesco Barreca,
• Enza Fazio,
• Cristiano D’Andrea,
• Paolo Matteini,
• Onofrio Maria Maragò and
• Pietro Giuseppe Gucciardi

Beilstein J. Nanotechnol. 2018, 9, 2718–2729, doi:10.3762/bjnano.9.254

• apex region (Figure 3c). This is a consequence of the burst-like behavior observed during the etching process. The tip length and its aspect ratio are determined by the meniscus height h (Equation 4), where h depends on the wire diameter, d, and contact angle, θc according to [46] where γE ≈ 0.577 is

• contact angle for a starting diameter of 125 µm (blue line) and 77 µm (orange line), corresponding to the initial wire size and to the wire diameter at the beginning of the second etching step. The meniscus height h2 predicted for the second etching step assuming very small contact angles (θc ≈ 0, Figure

• , t2 = 90 s, V2 = 2.1 VDC). (a) SEM image of a tip highlighting the dimensions of the tapered zones. The dashed lines are a contour of the upper taper that would have been obtained in a single step etching. (b) Plot of the expected meniscus height as a function of the contact angle assuming a wire

Characterization of the microscopic tribological properties of sandfish (Scincus scincus) scales by atomic force microscopy

• Weibin Wu,
• Christian Lutz,
• Simon Mersch,
• Richard Thelen,
• Christian Greiner,
• Guillaume Gomard and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2018, 9, 2618–2627, doi:10.3762/bjnano.9.243

• contact angle of sandfish scales was measured with the sessile drop method using an OCA 40 system with the corresponding SCA20 software (DataPhysics Instruments, Germany) Results and Discussion It is well-known that many parameters influence the frictional properties of surfaces. Comparable small

• contact angle of a single sandfish scale is about 100° (droplet volume 1 µL). SEM images of some probes used in this study. (a) Sharp tip of a conventional AFM cantilever made from silicon. (b) Sand particle glued to the end of a tipless cantilever (“sand probe”). The inset is a side view. (c) Glass

Au–Si plasmonic platforms: synthesis, structure and FDTD simulations

• Anna Gapska,
• Marcin Łapiński,
• Paweł Syty,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2018, 9, 2599–2608, doi:10.3762/bjnano.9.241

• of the contact angle in this system is about 40° [2]. As a consequence, Au–Si nanodroplets do not dissolve on the Si surface, forming the nanostructures during cooling. In the case of the studied layers, it cannot be unequivocally determined which of the two processes discussed above dominates at the

Friction reduction through biologically inspired scale-like laser surface textures

• Johannes Schneider,
• Vergil Djamiykov and
• Christian Greiner

Beilstein J. Nanotechnol. 2018, 9, 2561–2572, doi:10.3762/bjnano.9.238

• lizards and insects [39][40][45]. There are four effects that are classically used to argue why laser surface texturing has a beneficial influence on tribological properties – the trapping of wear debris [46], changes in the contact angle [47], the storage of lubricant [48] and an additional micro

• -hydrodynamic pressure build-up effect [49] – however, these seem not to be able to explain our results presented here. Wear is negligible in our experiments (see below), changes in contact angle between the differently textured surfaces are expected to be minimal, and there cannot be any storage of lubricant

A visible-light-controlled platform for prolonged drug release based on Ag-doped TiO₂ nanotubes with a hydrophobic layer

• Caihong Liang,
• Jiang Wen and
• Xiaoming Liao

Beilstein J. Nanotechnol. 2018, 9, 1793–1801, doi:10.3762/bjnano.9.170

• to modify the surface of nanotubes. In the present work, NDM was chosen to alter the hydrophilic layer to hydrophobic by attaching it to the Zn-Ag-TNTs material. The contact angle of NDM-Zn-Ag-TNTs (118°) in Figure 5d demonstrates that the surface wettability of nanotubes does transform from

• diffraction (XRD, SHIMADZU 61000, Japan), respectively. The chemical composition of the prepared samples was characterized by energy dispersive X-ray spectroscopy (EDS, Oxford) attached to the SEM. The wettability of the samples was measured by a contact angle meter (JC2000C1; Shanghai, China), and all of the

• contact angle measurements were conducted in triplicate. The light absorbance of bare TNTs, Ag-TNTs, Zn-Ag-TNTs and NDM-Zn-Ag-TNTs samples ranged from 450 nm to 800 nm and was detected by a UV–vis spectrophotometer (U-3010, Hitachi, Japan). X-ray photoelectron spectrometry (XPS, Escalab 250Xi, USA) of Zn