Simplified method of the quantum chemical analysis for determination of thermodynamic parameters of 2D cluster formation of amphiphilic compounds at the air/water interface

Vysotsky, Yu. B.; Belyaeva, E. A.; Vollhardt, D.; Aksenenko, E. V.; Miller, R.

doi:10.1016/j.jcis.2008.06.059

Cited by 14 publications

(42 citation statements)

References 11 publications

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“…To assess the clusterization thermodynamic parameters per monomer of a 2D film, we used the “simple method” that was developed by us earlier . This method allows calculating the values of Δ H 298 Cl / m , Δ S 298 Cl / m , and Δ G 298 Cl / m for monolayers using the corresponding parameters only for dimers with a certain arrangement of the dipole moments of the monomer head groups in them.…”

Section: Results and Discussionmentioning

confidence: 99%

Surface pK_a of Saturated Carboxylic Acids at the Air/Water Interface: A Quantum Chemical Approach

Vysotsky

Kartashynska²,

Vollhardt

et al. 2020

J. Phys. Chem. C

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In the present study a theoretical approach is proposed for the pK a estimation of monolayers at the air/water interface on the basis of saturated carboxylic acids. This model involves calculating only the Gibbs energies of formation and dimerization of carboxylic acid associates in the neutral and dissociated forms, as well as the corresponding monomers in the water and gas phases. The model does not require the construction of any thermodynamic cycles. The calculations are performed using semiempirical quantum chemical methods PM3 and PM6 within the framework of the conductor-like screening model for monomers and dimers of carboxylic acids C n H 2n+1 COOH (n = 6−16). It is shown that the minimum clusterization Gibbs energy corresponds to associates with the degree of dissociation α = 0.5. A relationship is derived between the surface and bulk pK a values. In particular, it follows from this that, unlike the bulk pK a , the surface pK a depends on the alkyl chain length of the surfactant. It is due to the difference between the solvation energies of the alkyl chains of the corresponding neutral and dissociated monomers. Thus, the calculated data show that the lengthening of the carboxylic acid chain by one CH 2 fragment leads to an increase in the surface pK a by 0.43 units. The obtained results are in good agreement with the available experimental data.

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Section: Results and Discussionmentioning

confidence: 99%

Surface pK_a of Saturated Carboxylic Acids at the Air/Water Interface: A Quantum Chemical Approach

Vysotsky

Kartashynska²,

Vollhardt

et al. 2020

J. Phys. Chem. C

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“…The series of previous works about thermodynamic parameter calculations of substituted alkanes at the air/water interface demonstrate that the parameter values calculated within the quantum-chemical semiempiric PM3 method (Mopac 2000) reproduce the corresponding experimental parameters 17,[23][24][25][26][27][28][29][30] with a good level of accuracy. As the thermodynamic parameters of the formation of monomers and dimers and the clusterization (for the Dimers 1) are very close to the parameters calculated previously using Mopac 2000, 17 it allows us to conclude that thermodynamic parameters of monomers and clusters of the substituted alkanes (particularly, carboxylic acids), calculated within Mopac 2012, describe the experimental parameters with the same accuracy.…”

Section: Tilted Monolayersmentioning

confidence: 95%

“…This fact is in agreement with previous results. 17,[22][23][24][25][26][27][28][29] Large and infinite clusters. The fragment of the monolayer of hexagonal structure was shown in Fig.…”

Section: Tilted Monolayersmentioning

confidence: 99%

“…11 include only the most thermodynamically preferable ''a''-type of intermolecular CHÁ Á ÁHC interactions. 23,24,29 Such a way of clusterization does not involve Dimers 1 formation besides they also contain only the ''a''-type of interactions. The formation of trimers is more preferable than the dimer formation: the trimer with the alkyl chain length of 16 carbon atoms contains 8 intermolecular CHÁ Á ÁHC interactions per one monomer whereas the dimer with the same alkyl chain length only 4.…”

Section: Tilted Monolayersmentioning

confidence: 99%

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The quantum-chemical approach to calculations of thermodynamic and structural parameters of formation of fatty acid monolayers with hexagonal packing at the air/water interface

Vysotsky

Belyaeva

Fomina

et al. 2014

Phys. Chem. Chem. Phys.

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The structural parameters of fatty acid (with formula CnH2n+1COOH, n = 7-16) monolayers at the air/water interface were modeled within quantum-chemical semiempirical program complex Mopac 2012 (PM3 method). On the basis of quantum-chemical calculations it was shown that molecules in the highly ordered monolayer can be oriented at the angle ∼16° (tilted monolayer), or at the angle ∼0° to the normal to the air/water interface (untilted monolayer). The structural parameters of both tilted and untilted monolayers correspond well to the experimental data. The parameters of the unit cell of the modelled tilted monolayer are: a = 8.0-8.2 Å and b = 4.2-4.5 Å (with the corresponding experimental data 8.4-8.7 Å and 4.9-5.0 Å). For the modelled untilted monolayer these parameters are: a = 7.7-8.0 Å; b = 4.6 Å (with the corresponding experimental data 8.4 Å and 4.8-4.9 Å). Enthalpy, entropy and Gibbs' energy of clusterization were calculated for both structures. The correlation dependencies of the calculated parameters on the number of pair intermolecular CHHC interactions in the clusters and the pair interactions between functional groups were obtained. It was shown that the spontaneous clusterization of the fatty carboxylic acids at the air/water interface under standard conditions is energetically preferable for molecules which have 13 or more carbon atoms in the alkyl chain and this result also agrees with the corresponding experimental parameters.

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“…Different types of interactions including hydrogen bonding have been successfully considered using semi-empirical quantum chemical methods. [44][45][46][47][48][49][50][51] Langmuir-Blodgett (LB) patterning is a new paradigm 52 for large-area patterning with mesostructured features on the basis of the well-established LB technique which is widely used for producing ultra thin self-assembled molecular coatings with controllable interfacial molecular orientation and packing. 53,54 Surface patterning has become an increasingly important phenomenon in nanoscience and for technologic applications, such as in the areas of micro-electronics, information processing and storage, nano/microfluidic devices, and biodetection.…”

Section: Sindrila Duttamentioning

confidence: 99%

Nanoaggregate shapes at the air/water interface

Vollhardt

Nandi

Banik

2011

Phys. Chem. Chem. Phys.

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Chiral interfaces and molecular recognition phenomena are of special interest not only for the understanding of biological recognition processes but also for the potential application in material science. Langmuir monolayers at the air-water interface have successfully been used as simple models to mimic biological phenomena. Recent experimental studies revealed that both chirality and molecular recognition processes of amphiphiles are controlling the features of the nano-aggregates at the air/water interface. The objective of experimental studies has been to gain information about the properties of mesoscopic length scale aggregates obtained on the basis of chiral discrimation effects and the formation of supramolecular entities by molecular recognition of non-surface active species dissolved in the aqueous subphase. Differences in the two-dimensional morphology and lattice structures of the nano-aggregates cannot be explained by macroscopic theories and needed information about the detailed orientation and distance dependence of the intermolecular interaction within the aggregates. First new bottom-up studies have been directed toward understanding the driving forces for the aggregation processes of monolayers. Different types of interactions have been successfully considered using semi-empirical quantum chemical methods. The possibilities of Langmuir-Blodgett (LB) patterning to be an alternative paradigm for large-area patterning with mesostructured features are discussed.

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Simplified method of the quantum chemical analysis for determination of thermodynamic parameters of 2D cluster formation of amphiphilic compounds at the air/water interface

Cited by 14 publications

References 11 publications

Surface pK_a of Saturated Carboxylic Acids at the Air/Water Interface: A Quantum Chemical Approach

Surface pK_a of Saturated Carboxylic Acids at the Air/Water Interface: A Quantum Chemical Approach

The quantum-chemical approach to calculations of thermodynamic and structural parameters of formation of fatty acid monolayers with hexagonal packing at the air/water interface

Nanoaggregate shapes at the air/water interface

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Simplified method of the quantum chemical analysis for determination of thermodynamic parameters of 2D cluster formation of amphiphilic compounds at the air/water interface

Cited by 14 publications

References 11 publications

Surface pKa of Saturated Carboxylic Acids at the Air/Water Interface: A Quantum Chemical Approach

Surface pKa of Saturated Carboxylic Acids at the Air/Water Interface: A Quantum Chemical Approach

The quantum-chemical approach to calculations of thermodynamic and structural parameters of formation of fatty acid monolayers with hexagonal packing at the air/water interface

Nanoaggregate shapes at the air/water interface

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Product

Resources

About

Surface pK_a of Saturated Carboxylic Acids at the Air/Water Interface: A Quantum Chemical Approach

Surface pK_a of Saturated Carboxylic Acids at the Air/Water Interface: A Quantum Chemical Approach