Control of Surface Crystallization of 1-Alcohol Monolayers by pH Changes in the Water Subphase

Bonosi, Francesca; Renault, and Anne; Berge, B.

doi:10.1021/la950647a

Cited by 8 publications

(12 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The thermodynamic clusterization parameters are calculated for molecules with the general formula C n H 2 n +1 OH ( n = 6–16). It is found that spontaneous clusterization process is possible for surfactants having no less than 11 carbon atoms in the alkyl chain, agreeing well with the results of numerous experimental studies. − The analysis of the calculated dependencies of the thermodynamic clusterization parameters per one monomer for small aggregates and 2D films suggests the possible way of the formation of the hexagonal monolayer phase via formation of alcohol trimers and their further aggregation up to the infinite monolayer structure. This assumption corresponds well with the small aggregation numbers m = 2.3–3.0 for the LE phase obtained by thermodynamic analysis of experimental π–A isotherms of homologues C 12 –C 14 alcohols. − …”

Section: Discussionsupporting

confidence: 82%

“…The existing experimental data show that condensed Langmuir monolayers of aliphatic alcohols with alkyl chains of 10–12 carbon atoms are formed at 4–25 °C. − The geometric parameters of their hexagonal unit cell are close to the relation b = a*√3 and vary within the range of a = 4.75–5.0 Ǻ, b = 7.5–8.5 Ǻ, t = 0–9°. ,− The molecules are arranged parallel to each other and are in linear conformation when all hydrogen atoms of methylene groups are in trans-configuration . It should be noted that molecular dynamic simulations of alcohol monolayers provided interesting new information (see, for example, refs and − ).…”

Section: Introductionmentioning

confidence: 83%

See 1 more Smart Citation

On Hexagonal Orientation of Fatty Alcohols in Monolayers at the Air/Water Interface: Quantum-Chemical Approach

et al. 2014

View full text Add to dashboard Cite

In the framework of the quantum chemical PM3 method, the monolayers of the aliphatic alcohols C n H 2n+1 OH (n = 6−16) of the hexagonal monolayer structure at the air/water interface are described. The calculated parameters of the monolayer unit cell are a = 4.3 Å ́; b = 7.4 Å ́, and t = 4°, which are in good agreement with the results of grazing incidence X-ray diffraction (GIXD) experiments a = 5.0 Å ́; b = 7.5 Å ́, and t = 0−9°. The optimized structures of small aggregates (dimers, trimers, tetramers, octamers, and nonamers) that comprised the hexagonal monolayer are obtained. The correlation dependencies of the clusterization enthalpy, entropy, and Gibbs' energy on the number of pair CH•••HC interactions and interactions between the functional groups realized in the cluster are obtained on the basis of calculated data. It is shown that spontaneous clusterization of aliphatic alcohols at the air/water interface under standard conditions is possible for molecules with an alkyl chain no shorter than 11 carbon atoms, which is in good agreement with the characteristics of the surface pressure−molecular area (π−A) isotherms. A way of hexagonal monolayer formation is proposed via preferential formation of trimers and their subsequent aggregation, which also agrees with existing experimental data processed using the thermodynamic model of equation of state for insoluble monolayers.

show abstract

Section: Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 83%

On Hexagonal Orientation of Fatty Alcohols in Monolayers at the Air/Water Interface: Quantum-Chemical Approach

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The translation of the parallels corresponds to 11.3 °C per one CH 2 difference in the chain length. The single point for n-decanol, which was adopted from the results of Berge et al 22 using their excess drop method, fits in well and allows an extension of the diagram in the direction of shorter and more soluble n-alcohols.…”

Section: Resultsmentioning

confidence: 84%

Phase Transition in Monolayers of Straight Chain and 2-Methyl Branched Alcohols at the Air−Water Interface

et al. 2002

View full text Add to dashboard Cite

Monolayers of straight chain and 2-methyl branched chain alcohols with alkyl chain lengths of C10−C18 are experimentally studied by a conventional film balance technique combined with a Brewster angle microscope (BAM). The comparison of the surface pressure (π)−area (A) isotherms with the corresponding BAM images provides information on the phase behavior and the first-order main phase transition of the monolayers. Striking differences in the dependence of the phase transition pressure on temperature of the straight chain and 2-methyl-substituted alcohols are correlated with differences in the molecular ordering. The general conditions for the main phase transition in the corresponding homologous alcohols can be derived. The effect of alkyl chain length and 2-methyl substitution on the general textural features of the condensed phase domains is determined under equilibrium and nonequilibrium conditions. n-Alcohol monolayers form defined and well-shaped condensed phase domains, often with inner texture in equilibrium. The long-range orientational order is strongly reduced in the condensed phase of 2-methyl-alcohols. Therefore, in the two-phase coexistence region of 2-methyl-alcohol monolayers only irregularly shaped domains without any inner structure are formed, which cannot be observed at the medium alkyl chain length C14 because of the low contrast. Model calculations of the two-dimensional lattice structure of the racemic 2-methyl-hexadecanol on the basis of the pg space group are performed and correspond well with the reduced ordering concluded from the experiments.

show abstract

“…X-ray grazing incidence, − , ellipsometry, , sum-frequency spectroscopy, , fluorescence, and Brewster angle microscopy and surface tension measurements ,,, show that monolayers of medium- and long-chain alcohols (C n H 2 n +1 OH; n = 9−16) present a 2D first-order liquid−solid phase transition upon decreasing temperature. For all the alcohols studied, this transition has been located more than 10 K above the melting temperature of the corresponding bulk phase.…”

Section: Introductionmentioning

confidence: 99%

Viscoelastic Behavior of 1-Dodecanol Monolayers Undergoing a Liquid−Solid Phase Transition. A Surface Quasielastic Light Scattering Study

et al. 2000

View full text Add to dashboard Cite

A surface quasielastic light scattering (SQELS) and electrocapillary wave (ECW) study of a monolayer of 1-dodecanol, obtained by placing a reservoir drop of the alcohol on top of a water surface, has been carried out as a function of temperature at different wavevectors. This monolayer goes through a liquid-solid phase transition at 312.1 K, more than 14 K above the freezing of bulk 1-dodecanol. The fit of the SQELS spectra gives the frequency, ωc, and the temporal damping, ∆ωc, of thermally induced capillary waves. In all the temperature range ωc follows Kelvin-like behavior (i.e., ωc ∼ q 3/2 ) leading to values of the apparent dynamic surface tension lower than the static ones. In addition the damping follows, ∆ωc ∼ q 1.2-1.4 very far from the expected ∼q 2 dispersion behavior. Both wave parameters show temperature trends compatible with the expected liquid-solid 2D phase transition at around 312 K. The expansion of the frequency range by using the ECW technique, shows that our experimental results cover the regions q e qR e q, where qR is the wavevector at which capillary-dilational resonance takes place. Within the classical elastohydrodynamic theory, our results can be accounted for if the dilational viscosity, κ, takes a negative sign. In these conditions mode mixing takes place for q g qR. Alternatively the experimental results can be quantitatively explained with κ ) 0 if an extra hydrodynamic coupling is included in the dispersion equation. From a physicochemical point of view this coupling may arise from the vicinity of the phase transition and/or molecular orientational effects promoted by the dilational wave. The small values of the dynamic elasticity, (ω), found in this work can be rationalized in terms of a monolayer-subsurface material transport, within the Lucassen-Van de Tempel model.

show abstract

Control of Surface Crystallization of 1-Alcohol Monolayers by pH Changes in the Water Subphase

Cited by 8 publications

References 10 publications

On Hexagonal Orientation of Fatty Alcohols in Monolayers at the Air/Water Interface: Quantum-Chemical Approach

On Hexagonal Orientation of Fatty Alcohols in Monolayers at the Air/Water Interface: Quantum-Chemical Approach

Phase Transition in Monolayers of Straight Chain and 2-Methyl Branched Alcohols at the Air−Water Interface

Viscoelastic Behavior of 1-Dodecanol Monolayers Undergoing a Liquid−Solid Phase Transition. A Surface Quasielastic Light Scattering Study

Contact Info

Product

Resources

About