Monolayer characterization of several short alkyl chain phosphoric acid extractants

Uphaus, R. A.; Vandegrift, George F.; Horwitz, E. P.

doi:10.1016/0021-9797(82)90306-x

Cited by 7 publications

(3 citation statements)

References 14 publications

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“…36,37 The calculated value for the molecular packing density of TOPO is based on the assumption that the dipole moment of TOPO is normal to the surface. Since EFM only measures the force gradient normal to the surface, a dipole normal to the surface will have a larger signal than that of a tilted dipole.…”

Section: Adsorption Dipole Moment and Screeningmentioning

confidence: 99%

“…For TOPO stripes, the upper limit of the calculated dipole density is about 170 times lower than expected for a dense layer of TOPO with the C 3V axis normal to the surface. 36,37 The calculated value for the molecular packing density of TOPO is based on the assumption that the dipole moment of TOPO is normal to the surface. Since EFM only measures the force gradient normal to the surface, a dipole normal to the surface will have a larger signal than that of a tilted dipole.…”

Section: Adsorption Dipole Moment and Screeningmentioning

confidence: 99%

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Electrostatic Force Microscopy Characterization of Trioctylphosphine Oxide Self-assembled Monolayers on Graphite

2000

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We have studied the self-assembling behavior of trioctylphosphine oxide (TOPO) on a highly oriented pyrolytic graphite surface. TOPO forms stripe-like structures in registry with the underlying graphite lattice. Using electrostatic force microscopy, we have also measured the charge, dipole, and dielectric constant of these monolayer films. The crystalline stripe phase has a net positive charge of about 2 × 10 -5 electron charge per TOPO molecule. The surface dipole due to adsorption is extremely small; this result implies that the dipole moment of TOPO is oriented parallel to the surface. Perfect image charges are not formed inside the graphite.

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Section: Adsorption Dipole Moment and Screeningmentioning

confidence: 99%

Section: Adsorption Dipole Moment and Screeningmentioning

confidence: 99%

Electrostatic Force Microscopy Characterization of Trioctylphosphine Oxide Self-assembled Monolayers on Graphite

2000

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“…这在支持信息图 S2 中得到验证: P507 单分子膜铺展在未加 HCl 的纯水表面, 得到的 π-A 曲线 [15,20] , 因为亚相纯水 pH 在酸性范围内变化, 单分子膜质子化程度改变, 分子极性端静电排斥作用带来的的影响并不会造成如此显著的分子面积的差异 [11] . 这种推测与 Uphaus 等 [21] 在研究短链磷类萃取剂单分子膜相变特征时的观点一致. 这就解释了图 2a 中 π-A 曲线的变化规律: 当亚相 pH 降低时, 界面处的 P507 分子溶于水相遭到抑制, 气-液界面处实际保留的 P507 分子总量增多.…”

Section: 结果与讨论unclassified

Interfacial Behavior of Acidic Organophosphorus Extractant Monolayer at Air-Water Interface: Subphase pH and Spreading Solvent Effect

高振¹,

黄焜²,

杜林³

et al. 2019

Acta Chim. Sinica

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The interfacial properties of extractant molecules have a significant impact on their complexation reaction activity with rare earth ions at liquid-liquid interface during solvent extraction. Although it is known that acidic organophosphorus extractant exists mainly in the form of dimers in nonpolar organic solvent, the research on solvent extraction kinetics has pointed out that the extractant molecules should react with rare earth ions in the form of monomers at the interface. Therefore, understanding the existing forms of acidic organophosphorus extractant at the interface will help comprehend the interfacial reaction process in solvent extraction. Traditionally, the interfacial properties of the extractant molecules were investigated by measuring interfacial tension isotherms and calculating interfacial adsorption parameters. However, this method can not provide the information of interfacial active species and the aggregation behavior of them. In order to clarify the characteristics of the interfacial behavior of organic extractant molecules at the interface, the effect of subphase pH and the polarity of spreading organic solvent on the adsorption and aggregation behavior of P507 molecules at the air-water interface were investigated by surface pressure-area isotherms and infrared reflectance absorption spectroscopy (IRRAS) based on Langmuir monolayer technique. It was found that P507 monolayers spread by n-hexane at the air-water interface had a certain solubility in the subphase water due to the ionization of the polar groups of P507 molecules. And the solubility decreased as the subphase pH decreased. Thus, the surface pressure-area isotherms changed significantly due to the total amount of P507 molecules remaining on the surface of water changed with the subphase pH. When the subphase pH decreased below 2.0, the influence of the solubility of P507 molecules became inapparent and the amount of P507 molecules remaining on the surface of

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Molecular Structure and Monolayer Properties

Hann¹

1990

Langmuir-Blodgett Films

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Monolayer characterization of several short alkyl chain phosphoric acid extractants

Cited by 7 publications

References 14 publications

Electrostatic Force Microscopy Characterization of Trioctylphosphine Oxide Self-assembled Monolayers on Graphite

Electrostatic Force Microscopy Characterization of Trioctylphosphine Oxide Self-assembled Monolayers on Graphite

Interfacial Behavior of Acidic Organophosphorus Extractant Monolayer at Air-Water Interface: Subphase pH and Spreading Solvent Effect

Molecular Structure and Monolayer Properties

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