Adsorption of Alkyldimethylamine and Alkyldimethylphosphine Oxides at Curved Aqueous Solution/Silica Interfaces, Studied Using Microcalorimetry

Pettersson, Alf; Rosenholm, Jarl B.

doi:10.1021/la025642+

Cited by 14 publications

(33 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, the binary water-surfactant phase diagrams of C 8 DMPO [21], C 10 DMPO [21], C 12 DMPO [2,3,21], and C 14 DMPO [2,3] were studied, and the formation of microemulsions with C 10 , C 12 , and C 14 DMPO was investigated [3]. Finally, there are studies on the interactions between C 12 DMPO surfactant layers adsorbed on hydrophobized mica [22] and on the adsorption of C 10 DMPO and C 12 DMPO on silica [23,24]. However, very few studies deal with the properties of the respective diethyl derivatives.…”

Section: Introductionmentioning

confidence: 99%

Purification, Surface Tensions, and Miscibility Gaps of Alkyldimethyl and Alkyldiethylphosphine Oxides

Blunk

Tessendorf

Buchavzov

et al. 2007

J Surfact & Detergents

View full text Add to dashboard Cite

Alkyldimethyl (C n DMPO) with chain lengths of n = 8 (octyl), 10 (decyl), 12 (dodecyl), and 14 (tetradecyl) as well as alkyldiethyl (C n DEPO) phosphine oxides with chain lengths of n = 10, 12, and 14 were synthesized and purified to study how the adsorption properties and the location of the miscibility gap of these surfactants depend on the size of the head group and on the length of the alkyl chain. After surfactant purification, the surface tension isotherms were determined from which the cmc, the minimum surface tension r cmc , the maximum surface concentration G max , and the minimum surface area A min were obtained. As expected, for one homologous series, a decrease in the cmc and an increase in G max was observed with increasing alkyl chain length. For two surfactants of the same alkyl chain length, the cmc values of the C n DEPO surfactants are approximately two times lower than those of the C n DMPO surfactants. However, the G max values of C n DEPO are lower than those of C n DMPO as two ethyl chains are sterically more demanding than two methyl chains. In addition to the adsorption properties, the location of the miscibility gap as a function of the alkyl chain length and the head group size was studied. Its location depends on the total number of carbon atoms and not primarily on the length of the main alkyl chain. This observation reflects the decreasing water solubility which can be tuned by increasing the length of either the main alkyl chain or of the shorter head group chains.

show abstract

Section: Introductionmentioning

confidence: 99%

Purification, Surface Tensions, and Miscibility Gaps of Alkyldimethyl and Alkyldiethylphosphine Oxides

Blunk

Tessendorf

Buchavzov

et al. 2007

J Surfact & Detergents

View full text Add to dashboard Cite

show abstract

“…DDAO molecules close to the mica surface were also proposed to have a higher ionization than those in the bulk solution . In another study using microcalorimetric experiments, adsorption of three different alkyldimethylamine oxides C n DAO ( n = 8, 10, and 12) were considered at natural pH . It was revealed from this study that at dilute concentrations the adsorption of surfactants is exothermic and enthalpically driven.…”

Section: Introductionmentioning

confidence: 88%

“…14 In another study using microcalorimetric experiments, adsorption of three different alkyldimethylamine oxides CnDAO (n = 8, 10, and 12) were considered at natural pH. 15 It was revealed from this study that at dilute concentrations the adsorption of surfactants is exothermic and enthalpically driven. The protonated amine oxide molecules and negatively charged surface ≡SiO − groups (siloxides) were found to reserve some of their counterions and hydrated water during their interactions.…”

Section: ■ Introductionmentioning

confidence: 94%

Adsorption of Dimethyldodecylamine Oxide and Its Mixtures with Triton X-100 at the Hydrophilic Silica/Water Interface Studied Using Total Internal Reflection Raman Spectroscopy

Ngo

Baldelli

2016

J. Phys. Chem. B

View full text Add to dashboard Cite

Adsorption of dimethyldodecylamine oxide (DDAO) and its mixtures with Triton X-100 (TX-100) at the hydrophilic silica/water interface has been studied using total internal reflection (TIR) Raman spectroscopy and target factor analysis (TFA). The use of a linear vibrational spectroscopic technique helps obtain information on molecular behavior, adsorbed amount, and conformational order of surfactant molecules at the interface. The results obtained from polarized Raman measurements of pure DDAO show insignificant changes in the orientation and conformational order of surface molecules as a function of DDAO bulk concentrations. The adsorption isotherm of pure DDAO shows a change in the structure of the adsorbed layer at concentrations close to the critical micelle concentration (cmc). TFA reveals that, for a low concentration of DDAO (0.30 mM in this study), adsorption of both DDAO and TX-100 in the mixed surfactants was enhanced at low TX-100 concentrations. The synergistic effect is dominant at low concentrations of TX-100, with enhanced adsorption of both surfactants. Although competitive adsorption is effective at high concentrations of TX-100, the presence of a small amount of DDAO at the interface still enhances TX-100 adsorption. When DDAO concentrations are increased to 1.00 mM, TX-100 replaces DDAO molecules on the surface when TX-100 concentration is increased.

show abstract

“…Consequently, the lowering of the surfactant content of the solution due to adsorption was infinitesimal. 5 For the same reasons, the increase in ionic strength due to dissolution of species from the silica surface at different pH values of solution is overlooked. The pH of the surfactant solutions (monitored with two decimals) did not drift during the experiments.…”

Section: Methodsmentioning

confidence: 99%

Streaming Potential Studies on the Adsorption of Amphoteric Alkyldimethylamine and Alkyldimethylphosphine Oxides on Mesoporous Silica from Aqueous Solution

and

Rosenholm

2002

Langmuir

Self Cite

View full text Add to dashboard Cite

We have used streaming potential measurements to determine the ζ-potential of amorphous, hydrophilic, mesoporous silica gel in aqueous nonionic−cationic solutions of the amphoteric alkyldimethylamine oxide surfactants (CnDAO with n = 8, 10, and 12) and alkyldimethylphosphine oxide surfactants (CnDPO with n = 10 and 12). The effect of different mixtures of the nonionic and cationic (protonated) forms of the amine oxide surfactant on the ζ-potential was studied at natural pH and at pH = 4. The nonionic phosphine oxide homologues were chosen as references. The surfactant contents ranged from dilute solutions to well above the cmc. The ζ-potential isotherms of the alkyldimethylamine oxides featured break points at the critical surface aggregation concentration (CSAC), recognized as the onset of counterion association with formed surface aggregates. The surface aggregates of all alkyldimethylamine oxide surfactants studied are charged at the cmc. At natural pH evidence of ζ-potential reversal was found as a result of the onset of formation of C12DAO hemimicelles induced by the surface with the adsorbed surfactant species. At pH = 4 the fractional counterion binding to surface aggregates, composed of almost only cationic−nonionic C12DAO dimers, varies exponentially with the surfactant content in solution, starting from zero at about the CSAC and reaching a plateau at the cmc. As expected, the adsorption of alkyldimethylphosphine oxides studied did not change the ζ-potential of silica. Nonionic C12DAO forms probably ellipsoidal aggregates; meanwhile cationic C10DAO and C12DAO are likely to form spherical surface micelles at the aqueous solution/SiO2 interface. The adsorption mechanism of nonionic C12DAO is different from that of cationic C12DAO, and consequently depends on the degree of protonation of the surfactant.

show abstract

Adsorption of Alkyldimethylamine and Alkyldimethylphosphine Oxides at Curved Aqueous Solution/Silica Interfaces, Studied Using Microcalorimetry

Cited by 14 publications

References 46 publications

Purification, Surface Tensions, and Miscibility Gaps of Alkyldimethyl and Alkyldiethylphosphine Oxides

Purification, Surface Tensions, and Miscibility Gaps of Alkyldimethyl and Alkyldiethylphosphine Oxides

Adsorption of Dimethyldodecylamine Oxide and Its Mixtures with Triton X-100 at the Hydrophilic Silica/Water Interface Studied Using Total Internal Reflection Raman Spectroscopy

Streaming Potential Studies on the Adsorption of Amphoteric Alkyldimethylamine and Alkyldimethylphosphine Oxides on Mesoporous Silica from Aqueous Solution

Contact Info

Product

Resources

About