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液态金属的表面张力,同分子或离子液体比较是很高的。许多有机液体的表面张力为20~40dyn/cm。水为100dyn/cm,熔盐一般为100~250dyn/cm,而液态金属一般要大于500dyn/cm。 在元素周期表中直到95号元素,实验测定的液态金属的表面张力只有75%。其中17%的液态金属表面张力较为精确,而6%是近似的。而且不同作者的测量偏差可达30~ 相似文献
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液体的表面张力与内压 总被引:1,自引:0,他引:1
在利用Onsager模型推导液体表面张力与内压间的关系时,文献[4]忽视了曲率对表面张力的影响,致使计算值与实验值的偏差较大。本文对此作了修正,建立了一个新的关系式,用实验数据检验表明,它能满意地适用于广阔温度范围内的各种液体。 相似文献
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在利用Onsager模型推导液体表面张力与内压间的关系时, 文献[4]忽视了曲率对表面张力的影响, 致使计算值与实验值的偏差较大。本文对此作了修正, 建立了一个新的关系式, 用实验数据检验表明, 它能满意地适用于广阔温度范围内的各种液体。 相似文献
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本文用中和法合成了基于烷基咪唑的甘氨酸离子液体[C3mim][Gly](1-丙基-3-甲基咪唑甘氨酸离子液体)和[c4miml[Gly](1-丁基-3.甲基咪唑甘氨酸离子液体),在298.15K下,0.0400-0.5000molkg^-1浓度范围内测定了不同浓度[C4mim][Oly]和[c3mim][Gly]离子液体水溶液的密度和表面张力,得到了溶液等张比容的实验值,提出了预测不同浓度溶液等张比容的经验方程,利用这个经验方程和李以圭等人提出的溶液表面张力模型,分别估算了这两种离子液体水溶液的表面张力,其估算值和实验值在误差范围内很好地吻合. 相似文献
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合成了基于烷基咪唑的乳酸离子液体[C4mim][Lact](1-丁基-3-甲基咪唑乳酸盐),并用1HNMR和DSC作了表征.由于乳酸离子液体和水易形成氢键,用通常的办法很难除去乳酸离子液体中的杂质水.为了排除杂质水的干扰,应用了标准加入法,配制一系列含有已知微量水的乳酸离子液体样品,在308.15~343.15K温度范围,用重量法测定了这些样品的密度,用最大气泡法测定了表面张力,用折光率确定了摩尔极化度,然后外推得到无水离子液体数据.在这些实验数据基础上,利用等张比容的加和性,估算了乳酸离子液体同系物[Cnmim][Lact](n=2,3,4,5,6)的表面张力、折射率、摩尔极化度、汽化焓和热膨胀系数,与实验数据相比有较好的一致性. 相似文献
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在278.15~338.15 K温度范围内, 分别用Anton Paar密度计和最大气泡法测定了含有不同微量水的离子液体EMIBF4 (1-ethyl-3-methylimidazolium tetrafluoroborate)的密度和表面张力, 讨论了微量水对这些性质的影响, 进而用标准加入法确定了无水离子液体EMIBF4的密度和表面张力. 借助Glasser理论和空隙模型讨论了EMIBF4的热力学性质. 用空隙模型计算的离子液体热膨胀系数与实验测定值较好一致, 说明空隙模型具有合理性. 相似文献
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测量液体表面张力的滴重法是使用设备简单、操作方便、温度易于控制、实验精确度较高的方法。钠易氧化,微量的沾污使其润湿特性产生很大变化,通常的滴重法难以获得钠的 相似文献
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液体表面张力是了解表面现象过程中的重要概念,然而物理化学教材对该概念的阐述却未能做到详实易懂。因此,通过较多立体图示,详细讨论了液体表面张力的产生原因、弯曲液面边缘所受表面张力的方向以及施力相界面等相关问题,以期对教材中未能阐述的内容作以适当补充,降低初学者在概念理解上的难度。 相似文献
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表面活性物质溶液的界面张力往往随时间而变,难以测得平衡界面张力J。Kloubek[1]曾应用经验式:1/(δH2O-δt)=b/(At1/2)+1/A,以[1/(δH2O-δt)]对1/t1/2作图外推求得溶液的平衡表面张力,但所得结果仅与文献值大致相符。本文从理论上分析该经验式的由来,以及产生偏离的原因,并寻求了解决的办法。 相似文献
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《Physics and Chemistry of Liquids》2012,50(3):175-180
Abstract In this work, new definitions of the normalized temperature and surface tension are proposed which result in a single plot for the surface tension of molten alkali metals. The functional dependence of the reduced surface tension on the reduced temperature can be adequately described by a straight line; the intercept and slope have been obtained using the linear regression approach. The method proposed herein predicts the values of surface tension at various temperatures with an average error of about 5%. 相似文献
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A method for directly determining interfacial tension without iteration from the difference in height between two capillaries
is presented. An experimental technique is described for organic liquids both lighter and heavier than water, in which the
menisci recede over surfaces wetted by the aqueous phase, thus providing the most favourable conditions for zero contact angle.
The values determined experimentally using tables prepared from the known shapes of sessile interfaces agree well with accepted
values of the interfacial tension. 相似文献
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表面活性剂和四烷基溴化铵的复配:Ⅲ.四烷基溴化铵碳氢链长对 … 总被引:2,自引:1,他引:1
本文考察了四烷基溴化铵(TAAB)碳氢链长对离子型表面活性剂SDS和DTAB在气/液表面吸附行为的影响。实验结果表明:与表面活性剂离子对应的添加剂反离子是影响其水溶液表面活性的主要因素,因而TAAB对SDS表现出明显的效应,对DTAB影响效果则是同浓度的NaBr类似,除了对表面活性离子头基电荷的静电屏蔽外,TAA^+的碳氢基团和SD^-碳氢链间还可能发生疏水相互作用,但后者受TAA^+离子体积制约 相似文献
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R. Wagner L. Richter Y. Wu J. Weißmüller J. Reiners E. Hengge A. Kleewein K. Hassler 《应用有机金属化学》1997,11(8):645-657
The surface tensions, wetting tensions, contact angles and solid/liquid interfacial tensions of defined siloxanes as well as those of analogous carbosilanes, polysilanes and neopentyl substituted silanes were determined. The wetting experiments were carried out on a glass plate coated with perfluoroalkyl methacrylate (FC 722®). The siloxanes possess the lowest surface tensions. Due to the presence of oxygen atoms in the siloxane backbone, a donor–acceptor portion (γ+/−lv) of the surface tension of about 1–2 mN/m was determined. The solid/liquid interfacial tension also contains a donor–acceptor portion (γ+/−sl). Its value is almost identical to that of γ+/−lv. The γ+/−sl differences between individual molecules of the same surface tension are responsible for contact angle differences of up to 4°. © 1997 John Wiley & Sons, Ltd. 相似文献
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Cristina Delgado M. Dolores Merchn M. Mercedes Velzquez Josefa Anaya 《Colloids and surfaces. A, Physicochemical and engineering aspects》2006,280(1-3):17-22
In order to study the effect of charge on the adsorption of surfactants at the air–water interface, two carboxybetaines have been synthesized with different number of separation methylenes between their charged groups. After purification and structure confirmation, the equilibrium and dynamic surface tensions were measured as a function of surfactant concentration for both the cationic and neutral forms of the surfactant molecules. The effect of ionic strength on the adsorption process was also studied. The equilibrium surface tension values were interpreted according to the Langmuir model and the dynamic surface tension data, converted to surface concentration by the Langmuir parameters, are consistent with the assumption of diffusion control over the range of surfactant concentrations studied. The diffusion coefficients show a progressive decrease in the rate of adsorption when the number of methylene units between the betaine charged groups increase. 相似文献
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The surface tensions of aqueous poly(N-vinylformamide) (PNVF), polyvinylamine (PVAM), and PNVF–PVAM copolymers were measured as functions of pH. The nonionic PNVF
gave a pH-independent surface tension of 68 mN/m. The surface tension of PVAM was pH dependent; at pH 10 it was 56 mN/m, whereas
it was 71.5 mN/m at pH 3.5. The transition from higher to lower surface tension values occurred most dramatically between
pH 8 and 9, reflecting the dissociation behavior of the amine groups. The copolymers showed intermediate behavior.
Received: 20 August 2001 Accepted: 26 September 2001 相似文献
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Suraj Chandra Sharma Lok Kumar Shrestha 《Journal of Dispersion Science and Technology》2013,34(4):577-581
The equilibrium, dynamic surface tensions, and surface dilatational elasticity of aqueous solutions of nonionic fluorocarbon surfactant are reported. The critical micellar concentration, CMC (0.023 mM) and equilibrium surface tension (24.6 m N . m?1) at CMC were measured by Wilhelmy plate method for aqueous solution of C8F17SO2N(C3H7)(C2H4O)nH (n=20), abbreviated as EF122A. The surface tension decay is slower for C8F17SO2N(C3H7)(C2H4O)nH (n=10) system, abbreviated as EF122B compared to the EF122A system over short time region, which indicates the slow transport of the surfactant molecules to the surface. The relaxation time for surface tension decay is estimated by fitting a series of exponentials to the dynamic surface tension data and it decreases with temperature for EF122A. Slow exchange of monomers between bulk and interface is reflected in the high elasticity value of the air‐liquid interface for EF122B compared with EF122A within measured frequency window (0.125–1.25 Hz). 相似文献