Thermodynamics and structure of liquid surfaces investigated directly with surface analytical tools**

Andersson, Gunther G.; Morgner, Harald

doi:10.1002/andp.201600230

Cited by 21 publications

(40 citation statements)

References 170 publications

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“…In order to describe dynamic macroscopic systems driven by surface tension and its gradients, assumptions about the influence of surfactant concentration are made to accurately describe interfacial rheology of surfactant systems 12 and physical phenomena dependent on it, such as soap film formation 13 or Marangoni flow 14,15 . The structure of surfactant layers at interfaces has been mainly studied using neutron reflectivity 16 , although other spectroscopic methods are also able to probe surfactant organisation 17,18 . In particular neutron scattering can be used to measure the surfactant concentration perpendicular to the surface to obtain the surface excess 16 .…”

Section: Introductionmentioning

confidence: 99%

Surfactant Interactions and Organization at the Gas–Water Interface (CTAB with Added Salt)

et al. 2018

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We have studied adsorbed layers of cetyltrimethylammonium bromide (CTAB) at air-water interfaces in the presence of added electrolyte. Fast bubble compression/expansion measurements were used to obtain the surface equation of state, i.e., the surface tension vs CTAB surface concentration dependence. We show that while a simple model where the surfactant molecules are assumed to be noninteracting is insufficient to describe the measured response of the surfactant layer, a modified Frumkin equation where the local interactions between the molecular components depend on their surface concentration captures the response. The variation of the effective interactions in the surfactant layer in the model shows that the interactions in the surfactant layer change from effectively repulsive to attractive with increasing surface concentration. Molecular dynamics simulations are performed to probe the origins of the change in the interactions. The simulations indicate that already at low surface concentrations the surfactants aggregate as highly dynamic rafts with surfactant orientation parallel to the interface. Increasing the concentration leads to a change in the assembly morphology at the interface: the surfactant layer thickens and the surfactants sample a range of tilted orientations with respect to the interfacial plane. The change from transient raftlike assemblies to dynamical aggregates at the interface involves a clear increase in the degree of counterion binding: we speculate that the flip of the effective interaction parameter in the model used to interpret the experimental results could result from this. The work here presents basic steps toward a proper understanding of the molecular organization and interactions of surfactants at an air-water interface. This is crucially important in understanding macroscopic properties of surfactant-stabilized systems such as foams, emulsions, and colloidal dispersions.

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Section: Introductionmentioning

confidence: 99%

Surfactant Interactions and Organization at the Gas–Water Interface (CTAB with Added Salt)

et al. 2018

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“…Combining both types of energy loss, the concentration depth profile of the elements in the sample can be determined. NICISS has also been used before to investigate liquid samples, polymer surfaces, and thin organic layers . Generally, a NICISS spectrum consists of energy loss spectra for each element in the sample.…”

Section: Methodsmentioning

confidence: 99%

“…NICISS has also been used before to investigate liquid samples, 26 polymer surfaces, and thin organic layers. 27 Generally, a NICISS spectrum consists of energy loss spectra for each element in the sample. The shape of the spectrum of each element is determined by its concentration depth profile in the sample.…”

Section: Methodsmentioning

confidence: 99%

“…Domain formation is typically observed at liquid surfaces of binary surfactant systems forming islands when differences in surface energy are large. It has been found that 1-palmitoyl-2-oleoyl- sn -glycero-3-phosphocholine (POPC) and cholesterol mutually influence the adsorption of each other at surfaces of polar liquids . Levy and Briggman have found that cholesterol and phospholipids form domains in biological membranes, and it is assumed that the weak interaction with the substrate plays a role in the domain formation .…”

Section: Introductionmentioning

confidence: 99%

“…It has been found that 1-palmitoyl-2oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol mutually influence the adsorption of each other at surfaces of polar liquids. 20 Levy and Briggman have found that cholesterol and phospholipids form domains in biological membranes, and it is assumed that the weak interaction with the substrate plays a role in the domain formation. 21 Miao et al have shown that, in the adsorption of self-assembled monolayers onto solid substrates, both molecule−substrate interaction and solvent effects play a role in the formation of bimolecular layers.…”

Section: Introductionmentioning

confidence: 99%

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Restructuring of Dye Layers in Dye Sensitized Solar Cells: Cooperative Adsorption of N719 and Chenodeoxycholic Acid on Titania

Trilaksana

Shearer

Kloo

et al. 2018

ACS Appl. Energy Mater.

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The effect of the co-adsorbent chenodeoxycholic acid (CDCA) up to a concentration of 20 mM on the adsorption of the dye N719 onto titania has been investigated using neutral impact collision ion scattering spectroscopy. It is shown that the co-adsorption of CDCA changes the adsorption mode of N719 from multilayer toward monolayer. FT-IR spectroscopy shows that the adsorption of CDCA increases with increasing CDCA concentration. In contrast, the amount of N719 adsorbed onto titania shows a minimum at 10 mM CDCA, and the relationship between the amount of CDCA and of N719 adsorbed onto titania depends nonmonotonically on the CDCA concentration. The co-adsorption of CDCA and N719 can be described as cooperative. The effect is observed for both low and high N719 concentrations.

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Dipole Formation at Active Materials/P(NDI3N‐T‐Br) Interface in Organic‐Based Photovoltaic

Alghamdi

Bjuggren

Pan

et al. 2022

Macro Materials & Eng

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In this work, a new potential electron transport material, poly[(N,N'-bis(3-(N,N-dimethyl)-N-ethylammonium)propyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-2,5-thiophene)]dibromide P(NDI3N-T-Br), is studied in conjunction with active layers formed by poly[2,3-bis(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1) and poly[[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)] (N2200). The energy levels of the active layer TQ1 and N2200 in contact with P(NDI3N-T-Br) have been determined by photoelectron spectroscopy. The dipole formed at the interface of the active layer and P(NDI3N-T-Br) is significantly different to the dipole formed at the respective interface with ITO. The dipole between the active layer and P(NDI3N-T-Br) blocks the transfer of holes from TQ1 to P(NDI3N-T-Br) which is desired, but the hole still transfers from the N2200 to P(NDI3N-T-Br) due to N2200 being an electron acceptor. This energy level alignment meets the expectation of using P(NDI3N-T-Br) as an interface layer in blocking the hole transfer to the interface layer when TQ1:N2200 is used in the active layer. The present work provides an understanding of P(NDI3N-T-Br) as charge extraction layer and indicates its potential to be used in organic photovoltaics.

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Thermodynamics and structure of liquid surfaces investigated directly with surface analytical tools**

Cited by 21 publications

References 170 publications

Surfactant Interactions and Organization at the Gas–Water Interface (CTAB with Added Salt)

Surfactant Interactions and Organization at the Gas–Water Interface (CTAB with Added Salt)

Restructuring of Dye Layers in Dye Sensitized Solar Cells: Cooperative Adsorption of N719 and Chenodeoxycholic Acid on Titania

Dipole Formation at Active Materials/P(NDI3N‐T‐Br) Interface in Organic‐Based Photovoltaic

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