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。     

几种农用增效助剂的表面张力及接触角研究

[目的]以期获得各种农用增效剂在植物靶标上的润湿铺展效果,并为田间应用提供理论指导.[方法]对4种助剂:有机硅类增效剂Silwet 408和Silwet(R)L-7608、非离子型增效剂SYNPERONIC 13/6.5-LQ-(TH)及植物源类增效剂LI-700的静态表面张力及动态接触角进行研究.[结果]通过测定上述...     

表面张力对微挤出流场的影响

针对表面张力对微挤出成型流场的影响,利用Polyflow软件进行了微圆管流场的数值模拟,研究了表面张力的尺度效应及熔体表面张力系数和接触角对微挤出流场的影响。结果表明,挤出口模尺寸越小,表面张力对熔体挤出胀大的影响越明显;挤出口模尺寸及熔体法向进口速度不变时,表面张力系数增大,熔体挤出胀大增大,挤出口模内熔体的进出口压强增大,自由表面出口负压增大;随着接触角的增大,熔体挤出胀大减小、挤出口模内熔体的进出口压强减小,自由表面出口负压先增大后减小。     

腐植酸溶液在煤表面接触角的实验研究

测定了不同浓度及不同ＰＨ值下黄腐酸溶液的表面张力及其在煤表面的接触角。结果表明：随浓度的增大,黄腐酸溶液的表面张力减小,而在煤表面的接触角增大;在酸性条件下随ＰＨ值的增大黄酸溶液在煤表面的接触角减小且变化明显,在碱性条件下,接触角变化不明显。     

接触角测量方法及其对纤维/树脂体系的适应性研究

接触角是衡量材料表面润湿性能的重要参数。接触角测试是材料表面探测的重要技术手段,通过接触角测试可得到固液、气液、气固界面相互作用的许多重要信息,诸如表面湿润性能、固液界面张力、表面粗糙度、化学多相性等。本文介绍了常见的接触角的测量方法,并针对玻璃纤维/树脂体系的特点,详细分析了常用接触角测量方法对玻璃纤维/树脂体系的适应性,以此探讨新的实验技术。     

接触角对粘接技术的应用

本文所介绍接触角对粘接技术的应用原理,以及接触角的测量与计算方法。     

无机盐对SDS溶液表面张力的影响

通过最大气泡法表面张力的测定,研究了无机盐NaCk、CuCl2、ZnSO4、AICI,和Al2(SO4)3等对十二烷基硫酸钠(SDS)溶液表面张力的影响.结果表明:在一定浓度范围内,随着无机盐浓度的增大,SDS溶液的表面张力逐渐减小;相同浓度的不同无机盐,价态越高,对SDS溶液表面张力降低越明显,3种无机盐对SDS溶液表面张力影响程度依次为:NaCl＜ZnSO4＜Al2(SO4)3.     

表面张力对传质过程的影响

表面张力对传质过程的影响主要是影响传质界面积,当物系为正物系时,对板式塔有较小较稳定的汽泡,对填料塔和湿壁塔,有较稳定的液膜,结果使二者均有较大的传质界面积,传质效果较好;负物系的情况相反。当液体混合物的平均表面张力较小时,也有利于形成较小较稳定的汽泡,从而有利于传质。表面张力对传质过程的影响机理相当复杂,这方面的研究工作有待深入开展。     

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。     

Some surface tension and contact angle problems in industry

Contact angle, surface tension and wetting properties are of fundamental importance in many industrial processes, e.g. coating of television screens and fluorescent lights. In addition, different stages of many processes may involve immersion cleansing and subsequent drying. We consider two different problems: one being very practical and involving cleansing and drying of silicon substrates in the semiconductor industry, and the other being theoretical whereby the problem of the shape of scssile and pendant drops is addressed with a possible practical application for making contact angle and surface tension measurements. In the case of cleansing of silicon substrates, we model a process whereby dirt particles are removed as a result of the surface tension forces exerted on a particle passing through a water/air interface and give a possible explanation as to why the efficiency of the process is vclocity dependent. For the case of small liquid drops, a new formulation of the governing equation yields solutions for multiple pendant and extended sessile drops.     

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.     

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。     

Surface properties of urethane coating containing perfluorinated additives

A series of alcohols containing perfluorinated segments F(CF₂)_m(CH₂)_n–OH (m = 8, 10 and n = 10) were synthesized. First, the alcohols were reacted with fatty acid to produce several esters (i.e. F(CF₂)_m(CH₂)_n–OOC–R (m = 8, 10 and n = 10)) containing perfluoro group by a condensation reaction, and characterized by FT-IR, GC, and surface tension. The esters were found to be soluble in ethyl ether, toluene, hexane, ethyl acetate, chloroform, and acetone, but insoluble in methyl alcohol, ethyl alcohol and isopropyl alcohol. Preliminary experiments on 1,2-dichloroethane solutions showed a remarkable decrease of surface tension upon the addition of the esters. In addition, the esters using urethane resin were coated onto a glass substrate using a spin-coating method. It was found that the contact angle of coated films ranged from 100° to 120°, depending on the structure of fatty acid esters. As a part of experiments, the water-repellency of coated paper and cotton was evaluated, and it was observed that the water droplet on the film surface was not permeated for 2 weeks.     

Contact Angles and Coating Film Thickness

The effect of film thickness and surface preparation techniques on contact angles of water, 1-bromonaphtalene, and n-hexadecane on Teflon® AF 1600 polymeric surfaces is studied. It was found that contact angles of water on different thicknesses of spin-coated films ranging from 27?nm to 420?nm are essentially constant. This is due to the homogeneity and smoothness of the coating layers as shown by the scanning force microscopy of the samples. Furthermore, the contact angle measurements with these three liquids on both dip-coated and spin-coated films suggested that the film preparation technique does not affect contact angles dramatically. Interestingly, slightly higher contact angles on dip-coated surfaces were measured. It is also argued that the anomaly of the water contact angle—in the sense that the measured contact angle is much higher than the expected ideal value—is due to specific interactions between water and Teflon®.     

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。     

Contact angle of surfactant solutions on precipitated surfactant surfaces

In this study, the contact angle of a saturated aqueous surfactant solution onto the surface of a precipitate of that surfactant is investigated. Those precipitates include fatty acids (C₁₀, C₁₂, C₁₄, C₁₆, and C₁₈), sodium salts of fatty acids (C₁₄, C₁₆, and C₁₈), calcium salts of fatty acids (C₈, C₁₀, C₁₂, C₁₄, C₁₆, and C₁₈). On virgin surfaces, free fatty acids and calcium salts of fatty acids have advancing contact angles (θ_A) between 77 and 92°, with little dependence on alkyl chain length for C₁₂ and higher alkyl chains. The sodium salt of a fatty acid has a lower θ_A than the free fatty or the calcium salt of the soap. The calcium salt of dodecyl sulfate has a lower θ_A than the calcium salt of dodecanoic acid (θ_A = 46 vs. 82°), but the calcium salt of the 18-carbon hydrophobes showed nearly the same contact angle for the soap and the alkyl sulfate. Greasiness, or slipperyness, or a scummy feel of a precipitated surfactant does not necessarily correspond to a hydrophobic surface.     

Low-rate Dynamic Contact Angles on Poly(methyl methacrylate/n-butyl methacrylate) and the Determination of Solid Surface Tensions

Low-rate dynamic contact angles of 12 liquids on a poly(methyl methacrylate/n-butyl methacrylate) P(MMA/nBMA) copolymer are measured by an automated axisymmetric drop shape analysis-profile (ADSA-P). It is found that 6 liquids yield non-constant contact angles, and/or dissolve the polymer on contact. From the experimental contact angles of the remaining 6 liquids, it is found that the liquid- vapour surface tension times the cosine of the contact angle changes smoothly with the liquid-vapour surface tension, i.e., γ_iv cos θ depends only on γ_iv for a given solid surface (or solid surface tension). This contact angle pattern is in harmony with those from other inert and noninert (polar and non-polar) surfaces [34-42, 51 -53]. The solid-vapour surface tension calculated from the equation-of-state approach for solid -liquid interfacial tensions [14] is found to be 34.4 mJ/m², with a 95% confidence limit of \pm 0.8mJ/m², from the experimental contact angles of the 6 liquids.