用接触角法测量聚合物共混体系的表面性能

利用接触角的方法研究了聚合物HDPF、PET及其共混物HDPE／PET的表面自由能、极化度以及与不同液体一水和甘油间界面张力的大小。     

羧甲基纤维素钠对表面张力和接触角的影响

本文利用各种样品的表面张力和接触角的实验数据,说明羧甲基纤维素钠对洗涤作用的影响。     

羧甲基纤维素钠对表面张力和接触角的影响

本文利用各种样品的表面张力和接触角的实验数据，说明羧甲基纤维素钠对洗涤作用的影响。     

Maximum Force Technique for the Measurement of the Surface Tension of a Small Droplet by AFM

An atomic force microscope (AFM) is used to measure the meniscus force on a vertical quartz rod as the rod is pulled through an air/liquid interface. A fluid bridge forms between the liquid and the base of the rod as the rod is withdrawn from the liquid. The force reaches a maximum as the bridge necks down and finally detaches from the rod. The maximum force on the rod is independent of the material of the rod and can be used to calculate the surface tension of the liquid. Alternately, if the surface tension of the liquid is known, the maximum force of the meniscus can be used to calibrate the spring constant of the AFM cantilever. The contact angle of the liquid on the rod was calculated as the rod was inserted into the liquid droplet. Contact angle hysteresis was observed. Results are presented of the measurement of the meniscus force of water, 10^-3 M cetyl trimethyl ammonium bromide (CTAB) and tetradecane as the rod is withdrawn from the liquid.     

Maximum Force Technique for the Measurement of the Surface Tension of a Small Droplet by AFM

An atomic force microscope (AFM) is used to measure the meniscus force on a vertical quartz rod as the rod is pulled through an air/liquid interface. A fluid bridge forms between the liquid and the base of the rod as the rod is withdrawn from the liquid. The force reaches a maximum as the bridge necks down and finally detaches from the rod. The maximum force on the rod is independent of the material of the rod and can be used to calculate the surface tension of the liquid. Alternately, if the surface tension of the liquid is known, the maximum force of the meniscus can be used to calibrate the spring constant of the AFM cantilever. The contact angle of the liquid on the rod was calculated as the rod was inserted into the liquid droplet. Contact angle hysteresis was observed. Results are presented of the measurement of the meniscus force of water, 10^?3 M cetyl trimethyl ammonium bromide (CTAB) and tetradecane as the rod is withdrawn from the liquid.     

Correlation between surface tension and physical paint properties

Surface tension is a parameter of decisive importance for characterizing painted and unpainted surfaces related to wetting and adhesion phenomena. Measurements of the surface tension of solids by means of an automatic contact angle measurement device are presented. The theoretical evaluations provide for a separation of the surface tension into polar and disperse components. In addition, this paper briefly touches on other more far-reaching approaches (acid/base) and discusses a method for the determination of the dynamic surface tension of liquids.     

花生壳粉表面性能及木塑复合材料界面性能的研究

通过动态法研究了浸润粉层的液体质量的平方随时间的变化规律,测定了不同探测液对花生壳的接触角。采用平衡接触角仪测定了探测液对改性聚乙烯的接触角,进而根据Focks理论推导出花生壳和改性聚乙烯的表面自由能及其极性分量和非极性分量,并计算出花生壳粉/聚乙烯复合材料的界面张力和黏附功。结果表明:相容剂Bondyram 5108的加入,使聚乙烯的极性分量和非极性分量都不同程度地增加,改善了花生壳粉在聚乙烯基体中的分散性,降低了复合材料的界面张力,增大了黏附功。     

Some curious observations of soap film contact lines

Contact lines between soap films and solid surfaces have been studied comparatively little. This is surprising, as a network of these contact lines constitutes the contact between an aqueous foam and an imperfectly wetted surface, and is critical for understanding foam slip on this type of surface. Data on the tension at a ‘creeping’ soap film contact line are presented. Surprisingly, given that viscous interactions were shown to be unimportant at these low velocities, this was substantially less than the sum of the ‘creeping’ tension for one wetting and one de-wetting contact line on the same surfaces. A possible explanation for this observation is presented, involving a free energy analysis of the deformed lamellae.     

纤维临界表面张力测定技术

用ＷＤＳ－Ｉ型接触角测定仪可测定纤维材料的临界表面张力，用硅烷偶联剂处理玻璃纤维，测定偶联剂处理前后玻璃纤维临界表面张力的变化，可了解偶联剂对玻璃纤维表面浸润性能的影响。因此临界表面张力测定技术是复合材料界面研究的一种重要方法。     

Surface energy measurements of coated titanium dioxide pigment

In this study surface energy measurements have been carried out on titanium dioxide pigments coated with different types of organic compounds. The organic coatings investigated were polymethylsiloxane and octyl triethoxy-silane. The level of coating applied was increased from 0.2 up to 1.5 wt%. Contact angles were measured using an advancing sessile drop method. To allow for the fact that measurements were made on pressed discs of particles rather than on a perfectly flat surface, a correction was applied to convert each measured contact angle to the true Young's contact angle. Surface energies were calculated from the corrected contact angles using the Owens and Wendt equation. From the values of surface energy it was possible to determine at what coating level the surface characteristics changed from hydrophilic to hydrophobic and hence when complete coverage had taken place. For both the siloxane and the silane coatings it was found that complete coating coverage occurred at an addition level of around 0.8 wt%. The surface energies of all the coated pigments were found to correlate well with their dispersion behaviour in liquid paraffin.     

Surface tension of Nanofluid-type fuels containing suspended nanomaterials

ABSTRACT: The surface tension of ethanol and n-decane based nanofluid fuels containing suspended aluminum (Al), aluminum oxide (Al2O3), and boron (B) nanoparticles as well as dispersible multi-wall carbon nanotubes (MWCNTs) were measured using the pendant drop method by solving the Young-Laplace equation. The effects of nanoparticle concentration, size and the presence of a dispersing agent (surfactant) on surface tension were determined. The results show that surface tension increases both with particle concentration (above a critical concentration) and particle size for all cases. This is because the Van der Waals force between particles at the liquid/gas interface increases surface free energy and thus increases surface tension. At low particle concentrations, however, addition of particles has little influence on surface tension because of the large distance between particles. An exception is when a surfactant was used or when (MWCNTs) was involved. For such cases, the surface tension decreases compared to the pure base fluid. The hypothesis is the polymer groups attached to (MWCNTs) and the surfactant layer between a particle and the surround fluid increases the electrostatic force between particles and thus reduce surface energy and surface tension.     

Surface properties and surface patterning of UV-curable coating using perfluorosilane-treated nanosilica

In this work, a one-step film formation method is demonstrated to obtain the patterned surface of an acrylate photocuring coating using nano-silica particles treated with a perfluoroalkoxysilane ((heptadecafluoro-1,1,2,2-tetra hydrodecyl) triethoxysilane) as a nanoadditive. Nanosilica particles were treated with perfluoroalkoxysilane and used in a UV-curable matrix. The typical patterns on the surface of the UV-cured films are revealed in AFM images. The surface properties of the cured films were investigated by measuring water contact angle and surface energy. The degree of conversion of the samples was obtained by FTIR analysis and pendulum hardness was measured using a Konig hardness meter. Scratch resistance of cured films was measured by standard scratch measuring pens. The characteristics obtained from AFM analysis showed that rough surface patterns in this system are controlled linearly by changes in the treated nano-particle concentration. The subtraction of surface energy of the cured film was clear and the water contact angle showed a 60% increase with the addition of a fluorinated nano-particle concentration. Surface hardness decreased and scratch resistance increased as the concentration of treated nanoparticles increased, while the final degree of conversion of the film remained unchanged.     

Surface modification of silica particles assisted by CO2

This paper reports the synthesis of coating silica particles, in order to design hybrid materials with hydrophobic surface properties. The silica particles were prepared in basic conditions under atmosphere of carbon dioxide (CO₂), using tetraethylorthosilicate (TEOS) as a precursor and octyltriethoxysilane (OTES) as a surface modifying agent. It was demonstrated that the contact angles of silica hybrid films could be changed by varying temperature and pressure of CO₂. The investigation of the prepared hybrid materials by dynamic light scattering (DLS) and environmental scanning electron microscopy (ESEM), respectively, showed that they consisted mainly of particles with a diameter of 100–250 nm. Fourier transform infrared (FT-IR) spectra indicate that the interaction between the coupling reagents, at different conditions, is mainly through chemical bonding.     

Elimination of Perfluorinated Surfactants – Adsorbent Evaluation Applying Surface Tension Measurements

The adsorption of perfluorooctane sulfonate (PFOS) onto activated carbons, nonfunctionalized polymeric adsorbents, and anion exchange resins was evaluated in batch as well as column experiments. It was found that the total PFOS capacity, adsorption kinetics, breakthrough times, and minimum effluent concentrations were highly dependent on the material properties, such as the inner surface area, pore size, functionalization, and hydrophobic character of the material, and on process parameters like temperature and ionic strength of the solution. The experiments furthermore revealed that surface tension measurements are a suitable method for online determination of PFOS concentrations above a defined value.     

Corrosion resistant performance of hydrophobic poly(N-vinyl imidazole-co-ethyl methacrylate) coating on mild steel

Functional copolymers are often used as protective coating against corrosion. In this research article, we have applied poly(NVI-co-EMA) coating over the mild steel surface which provides barrier protection against corrosion in aggressive environment. Hydrophobic nature of the copolymer film may augment the corrosion resistance behavior and thermal stability of the copolymer also influences the corrosion protection. Thus, the coating precluded the corrosive elements and corrosion products from diffusing through the coating. EIS technique revealed that the mild steel coated with hydrophobic copolymer film, which is immersed in 3% NaCl solution provides excellent protection from corrosion. Further, it is evidenced by protection efficiency of the copolymer which is greater than 90%. The results from surface analysis techniques like SEM, AFM and FTIR also supports and confirms a very thin film on the metal surface with excellent anticorrosion effects.     

Surface properties of polymer films including multiblock copolymer

B(AB)_n multiblock copolymers of which the A block and the B block are hydrophobic and hydrophilic, respectively, were blended into crosslinkable coating compositions for preparing a hydrophilic surface, and compared with the graft copolymers including A and B as the pendant groups. The main constituent of A was polydimethyl-siloxane and that of B was poly(ethylene oxide). While the block copolymer slightly increased the hydrophobicity of the surface, it quickly became hydrophilic on contact with water. On the contrary, the graft copolymer increased the hydrophobicity even after its contact with water. Elementary analysis with ESCA demonstrated that both the silicon atoms and ether groups were concentrated on the very top of the surface in the films including the block copolymers but only silicon atoms were concentrated on the film surface which included the graft copolymers. In spite of their propensity to remain in the bulk due to their high surface energy, hydrophilic poly(ethylene oxide) moieties in the block copolymers migrated onto the near surface accompanying the movement of the hydrophobic polydimethyl-siloxane. because their mobility would be restricted by the bonding of both sides. Inclusion of the block copolymers significantly improved soil resistance. The advantage of the block copolymers as a surface modifier was further developed as an adhesion promoter. The introduction of a larger amount of the hydroxyl group into the hydrophilic block was effective for this purpose. This was discussed with respect to the change in the γ_p parameter.     

Surface properties of a segmented polyurethane containing amphiphilic polymers as additives

Two different types of amphiphilic polymers were used as surface-modifying additives to a polyetherurethane, Pellethane 2363–75D, which has T_g close to room temperature. The additives used were a segmented polyetherurethane designated Pol C, and Pluronics PE6800 and PE9400, i.e., triblock copolymers of propylene oxide and ethylene oxide. Pol C was prepared from poly(ethylene glycol), methylene diphenylene diisocyanate, and a fatty acid monoglyceride. The properties of the blends were investigated in their unhydrated state and after water immersion at 23°C and 80°C. Surface composition, water absorption, and leakage of additives to the aqueous phase have been studied. From ESCA and contact angle measurements it was concluded that Pol C was enriched in the surface layer of the matrix material after water immersion at 80°C. The Pluronics showed less effects on the surface properties of the matrix material, probably because of their high water solubility. © 1994 John Wiley & Sons, Inc.     

Surface coating properties of different shape and size pigment blends

The effect of different shape and size of pigments in blends on latex coating surface properties was investigated. Two pigment blends were compared. Both blends were made of plate-like kaolin pigment but with different size prismatic precipitated calcium carbonate at different volume ratios. All coatings were applied on absorbent as well as non-absorbent substrates. Surface coating properties investigated include surface morphology, surface chemistry and surface energy. Surface morphology was characterized by measuring gloss and roughness, surface chemistry was characterized by X-ray Photoelectron Spectroscopy and surface energy was estimated by Kaelable approach.     

ＴＡＴＢ与氟聚合物界面张力及粘附功的计算

用ＴＹ－８２株皎皎 测定仪测定了三氨基三硝基苯（ＴＡＴＢ）、氟聚合物与标准溶液的接触角,用几何平均法计算ＴＡＴＢ与不同氟聚合物的界面张力及粘附功,结果表明,ＴＡＴＢ与氟聚合物间界面张力及粘附功的大小主要由它们的极性匹配情况决定,极性越区配,则界面张力越小,附粘功越大,粘接越牢固。