Oberflächen mit Rauhigkeiten im Nanometer-Bereich und erhöhter Benetzbarkeit halten dem Vereisen merklich länger stand als typisch superhydrophobe Oberflächen mit erhöhter hierarchischer Rauhigkeit und verminderter Benetzbarkeit. The best cleaning efficiency has been measured for Genapol® LRO (alkyl diglycol ether In cooperation with CAM-D Technologies GmbH Oberflächen: Funktionserhaltung durch Regeneration”. Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies. In addition, the predicted degree of counterion binding yielded a lower bound to the experimentally measured value. The environment for methylene groups in the hemimicelle is more favorable than that in a micelle. At this concentration, hemimicelles resulting from lateral interaction between adsorbed surfactants first appear on the most energetic surface patches. However, at the pH values considered, the pH sensitivity of C16Bet could be neglected, and it was equivalently modeled as a zwitterionic surfactant. Roughness enhances hydrophobicity of a solid surface leading to high contact angles with water. Results obtained in this study on the thickness of adsorbed surfactant films, as well as on adsorbed amounts, are in good agreement with those obtained by other techniques. In nonionic NP-15 rich mixtures, negative hysteresis is observed for the desorption of both TTAC and NP-15. hydrophobic oily/greasy soils at low concentrations without damaging the surface. Objekte beliebiger Größe und Form können beschichtet werden. droplet size), microscale (surface texture size), and nanoscale (molecular size). The best cleaning efficiency has been measured for Genapol® LRO (alkyl diglycol ether At still higher concentrations, successively less energetic patches are sites for two-dimensional phase transitions forming hemimicelles. sample, the super- hydrophobic plastic surface showed smaller roughness and higher waviness The use of ion-selective membrane electrodes for, In article 1 of this series, we developed a molecular-thermodynamic (MT) theory to model the micellization of mixtures containing an arbitrary number of conventional (pH-insensitive) surfactants. As in the case of benzene, the Ham bands of pyrene were assigned to the 0–0 and ag-vibration bands. The isotherm of the C14E6−C10E6 system exhibits a maximum at low total concentrations, while the C12E5−C12E8 system acts as a single surfactant system with similar cmc but intermediate adsorbed amount compared with those of the individual components. conventional surfactant, which effectively behave like ternary surfactant mixtures. Non-contact, optical profilometry parameters. By the solution of equations of adsorption, one can obtain directly the values of surface excess of all components (surfactant ions, counterions, and nonionic surfactants molecules), which are present in the investigated system. Subsequent mechanical load tests showed the resistance of the functionalization. But the micelle-to-vesicle or vesicle-to-micelle transitions induced by the increase of temperature have not been observed at the studied temperature range. The thermodynamic parameters ΔG10, ΔH10, and ΔS10 for these two steps were determined. However, it is currently becoming well established that both models explain the wetting behavior more from a qualitative or practical point of view rather than giving a quantitative description. Request. Superhydrophobic surfaces were fabricated by the complex coating of silica nanoparticles with functional groups onto cotton textiles to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane or their combination. In cooperation with CAM-D Technologies GmbH Both surfactants display pronounced cooperative adsorption behavior (S-shaped isotherms). The dynamic contact angle measurements revealed that the glass surface was In addition, use of RSA has been extended, with fair success, to predict partition coefficients of ternary surfactant systems using data of binary surfactants systems. In conclusion, in cooperation with the industrial project partners a cleaning agent for micro- and The conical micro structures were varied in diameter and height ranging from 5 to 20 μ$\upmu $ m as were the process parameters within the framework of a statistical experimental plan. property not covered in the first two editions). about 156.1° ± 3.7°, 177° and 156°, respectively. Scanning electron microscopy, contact In general the superhydrophobic plastic surface was easier to clean than the The cationic surfactants dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), A novel separation technique known as an aqueous surfactant two-phase (ASTP) extraction is a promising method to remove organic contaminants from wastewater. This is because TiO2 has the most efficient photoactivity, the highest stability and the lowest cost. The stability of the lamellar phase is a function of the periodic repeat distances and surfactant head group areas as measured by small angle X-ray scattering, and the results are discussed in terms of the inter- and intra-bilayer interactions. a contact angle of 167.7° ± 1.5°. The results show that these mixed cationic/nonionic surfactant mixtures (II to X) can be used to inhibit, A simultaneous determination of cationic and nonionic surfactants has been developed using ion-association titration. ), the adsorption increases dramatically as hemimicelles form on the adsorbent through association between hydrocarbon chains of the adsorbed molecules. the surface. excellent. The MT theory presented here represents the first molecular-based quantitative description of the micellization behavior of mixtures of pH-sensitive surfactants and conventional surfactants, and allows qualitative and quantitative predictions of the micellization behavior of a variety of surfactant systems. grayscale evaluations. Mixed surfactants may improve the performance of surfactant-enhanced remediation of soils and sediments by decreasing the applied surfactant level and thus remediation cost. Although the pH values of solutions with no added acid were modeled with only qualitative accuracy, the MT theory resulted in quantitatively accurate predictions of solution pH for mixtures containing added acid. Oberflächen: Funktionserhaltung durch Regeneration”. µm, The wetting behavior of superhydrophobic surfaces can be classified into two types, in terms of the variation of contact angle with surfactant concentration cs. Antifingerprint- Oberflächen. For non-wetting liquids the contact angle with a rough surface is greater than with a flat surface and may approach 180°, as reported for leaves of water-repellent plants, such as lotus. cleaning formulation were examined using several optical methods. template_1. Roughening or texturing surfaces provides super-liquid repellent or film forming properties without alteration of the surface chemistry. 172° were measured. Die Forscher aus Bonn, Rostock und Karlsruhe haben nun enträt- cleaning process and the resulting adsorption of surfactants at the surfaces. Es erfolgt eine Optimierung der Herstellungsprozedur durch die Verwendung gebogener SH-Oberflächen, was den Eintrocknungsprozess beschleunigt und die räumliche Orientierung von A festlegt. The interaction parameters that measure the interaction between the surfactant molecules in the mixed micelle were computed by Rubingh's approach. The MT theory was validated by examining mixtures containing both a pH-sensitive surfactant and a, Benzene, toluene, ethylbenzene, and xylene are frequently observed contaminants in industrial wastewaters causing concerns about environmental and health effects. Hier könnt ihr unser wissenschaftliches Protokoll zum Abschluss der Forschungsarbeit lesen. a minimum of mathematics in explanation of topics, making it The adsorbed layer structure observed at the different surfaces was interpreted in terms of the effective interaction between different parts of the surfactant and the solid surface. UV/VIS-spectroscopy was best suited for a quantitative analysis of the cleaning In recent years These results justified the strong relationship between the corrosion inhibition efficiency and the micellar interaction parameters of the mixed surfactants which used as an organic corrosion inhibitors. An aqueous surfactant two-phase (ASTP) extraction system using mixtures of cationic and anionic surfactants have been shown to be a promising surfactant-based separation technique to concentrate solutes such as proteins and dyes from, The stability of the lamellar phases formed with the anionic surfactant sodium 4-(1′-heptylnonyl)benzenesulfonate, the cationic surfactant didodecyldimethylammonium bromide, and the nonionic surfactant pentaethylene glycol mono-n-dodecyl ether (C12E5) is reported as water is gradually replaced with propylene glycol. The anomalously large Ham effect observed in pyrene has been studied in various solvents at room temperature by measuring the fluorescence and absorption spectra. III. The variation of these group adsorption energies with intramolecular electronic and steric effects was also studied. The mixed micelles remain spherical with SDS and Triton X‐100. The addition of inorganic salts and alcohols will increase and decrease the value of nhm, respectively. surfactant), superspreading (or superwetting) by aqueous surfactant Superhydrophobe Oberflächen haben eine ausgeprägte Oberflächenstruktur mit Nano- und Mikrometer großen Vorsprüngen. ist inzwischen möglich, superhydrophobe Oberflächen nach dem Vorbild der Natur zu konstruieren. The effect of relative humidity is also investigated to study the environmental effects on adhesion and friction. The parallel determination of the average aggregation number (N) and aggregate number density (Nag) in the fragmented-phase domain shows three distinct regimes: (i) a growing regime, from θ = 0 to θ = 0.17, where the size of the surface aggregates increases at constant number density; (ii) a self-repeating regime, from θ = 0.17 to θ ∼ 0.5, where the number density increases, while the size of the aggregates remains constant; the surface aggregates in this regime are undistinguishable from the regular micelles formed by TX 100 in aqueous solution (N = 110); (iii) again a growing regime, up to a point (θ = 0.8) where the adsorbed phase can be described as an assembly of surface micelles (N = 200) in close packing. For the cleanability studies of the standard soil eleven additional surfactants were considered in recommendations for the design of superhydrophobic surfaces are formulated. the contaminated areas and that can be easily removed after cleaning by rinsing without damaging sulfate sodium salt, 78%) and REWOPOL® SB DO 75 (di-isooctyl sulfosuccinate, 87%). In recent years Based on the assumption that each adsorbed surface-active cation in the first plateau is an active centre for surface aggregation, the minimum average aggregation number of hemimicelle, nhm, is equal to the ratio between the adsorption amounts of two plateaux, Γ∞2nd and Γ∞1st, or, more generally, between Γcmc and Γhmc, the values of adsorption at the c.m.c. IV. are consistent with half-cylinders on crystalline hydrophobic substrates, full cylinders on mica, and spheres on amorphous This suggests that the formation of cationic/anionic surfactant complexes reduces the electrostatic adsorption barrier. Patent, DE 10 … following the total wetting Wenzel regime whereas the plastic surface could be described by the The effect of micropatterning and nanopatterning on the hydrophobicity was investigated for two different polymers with micropatterns and nanopatterns. surfactant concentration, surfactant structure and type of contamination were investigated. Finally, we have to identify bacteria and viruses, achieving ultimate speed and ultimate sensitivity of their detection. The wettability and morphology of the as-fabricated surfaces were investigated by contact angle measurement and scanning electron microscopy. Observed trends due to change in salt concentration, temperature and oil type, and due to the addition of cosurfactants, are correlated and emerge from a simple global framework. They exhibited inhibition efficiency expressed by the rate of corrosion as 5.15 and 1.53 miles per year respectively, at 400 ppm. When cationic and anionic surfactants are mixed at certain surfactant concentrations and compositions, the solution separates into two immiscible aqueous phases. fundamental physical mechanisms of wetting, including the transition between Various leaf surfaces on the microscale and nanoscale have been characterized in order to separate out the effects of the microbumps and nanobumps and the wax on the hydrophobicity. To achieve low contact angle hysteresis along with a high contact angle, superhydrophobic surfaces should form composite interface (0) with air pockets in the valleys between asperities. Non-contact, optical profilometry Comparisons with adsorption on silica, Contact Angle Hysteresis. The molar enthalpies of aggregate formation at the silica/water interface were found to be close to those in the bulk solution, indicating that surface aggregation and bulk micellization are very similar phenomena. The tendency to form dye–cationic surfactant complexes in a micellar solution of the nonionic surfactant decreases as the hydrophile–lipophile balance of the nonionic surfactant increases. It is the combination of surface roughness and low-surface-energy modification that leads to superhydrophobicity. The resulting experimental relationships are compatible with a hydrogen-bonding adsorption mechanism on silica, but not on alumina. The present thesis is part of the BMBF project “Biomimetische superhydrophobe Molecules of biological importance and especially proteins, nucleic acids and glycopolymers, are the targets, where the principles of biomolecular recognition are of great utility. Oberflächen ein außerordentliches Verhalten hinsichtlich Eis-Resistenz und Gefrierverzögerung. The unique surface structure of the lotus leaf in combination with hydrophobic epicuticular wax Starting with the outside of the epidermis cell, ones finds the outermost layer of a thin extracellular membrane, called cuticle. The values of the amplitude parameters Ra, Rq and Rz for the plastic surface are 0.920 We show, on the basis of experimental evidence, that there can be two contact angles on the same rough surface, depending on how a drop is formed. models. This is always attributed to the formation of cationic surfactant complexes through the electrostatic attraction of hydrophilic groups. Here, we review the progress of the scientific research on TiO2 photocatalysis as well as its industrial applications, and describe future prospects of this field mainly based on the present authors' work. The wettability of hydrophobic surfaces is generally improved by surfactant solutions. Contact angle is controlled by surface tension for common linear surfactants and becomes independent of cs as cs>critical micelle concentration. It is not clear whether microstructures or nanostructures or their certain combination on the surface, are required for superhydrophobicity. 95 KONSTRUKTIONEN UND GERÄTE 97 Turbinenoptimierung nach dem Riesenhaiprinzip 99 Windkonzentrator „Berwian“ 100 Bionische Schaufelprofile für einen Axialventilator 101 Windradblätter mit „Schmetterlingsschuppen“ 102 Frost formation in cold environments is causing massive ongoing socioeconomic costs, due to material damage, energy waste, and measures for the prevention of hazards , .Numerous commercial sectors are affected by the negative impact of frost formation, such as the automotive, aerospace, railway, telecommunication, and power engineering industries , , . In this article, we extend the MT theory to model mixtures containing a pH-sensitive surfactant. 172° were measured. typical basic cleaning formulation and the influence of the additives as a function of surfactant Superhydrophobic functional surfaces have numerous applications. these cleaning results were utilized to evaluate a relationship between the surfactant structure The cmc's predicted using the MT theory agreed well with the experimental cmc's and were found to be comparable to and sometimes better than the cmc's determined using the regular solution theory (RST), even though the empirical RST utilizes experimentally measured cmc's as an input. Four different surfactants were examined and the cationic surfactant TEGOTENS® DO of biomimetic superhydrophobic surfaces have been fabricated by mimicking the structure of the While in the low-affinity region the amount adsorbed and the integral enthalpies of displacement are only slightly smaller for C8G1 than for C8E4, the deviation increases to 1 order of magnitude in the aggregative adsorption region. Spray techniques have been demonstrated to be more effective in the cleaning of structured surfaces devised a suspension of coated titanium dioxide nanoparticles that can be spray-painted or dipcoated onto a range of hard and soft surfaces, including paper, cloth, and glass. Most of the organic contaminants tend to solubilize and concentrate in the surfactant-rich phase, leaving the surfactant-dilute phase containing only small amounts of contaminants as remediated water. 2). To read the full-text of this research, you can request a copy directly from the author. Verification of the model is conducted using experimental data for the contact angle of water droplet on a lotus leaf surface. Results of dynamic surface properties show that MQAS/TX-100 mixtures exhibit the best dynamic surface activity among these surfactant mixtures, resulting from the good dynamic surface activity of TX-100 and the weak interaction between MQAS and TX-100. We also compared predictions to data from the literature for mixtures of C12DAO and SDS. Branching decreases the contribution of hydrophobic interactions to two-dimensional condensation (hemi-micelle formation) at the solid-liquid interface.