An analytically solvable numerical approximation to Ward-Tordai equation applied to Langmuir adsorption

Nele, Márcio

doi:10.1016/j.colsurfa.2022.129186

Cited by 1 publication

(1 citation statement)

References 14 publications

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“…The values of the diffusion coefficient were investigated in the range from 10 −16 to 10 −7 (m 2 /s). In order to solve the non-linear Ward-Tordai integral equation associated with the Langmuir isotherm, the Nystrom method was applied [38][39][40]. Equation ( 5) was discretized, and its final form is given by Equation (10), with the initial step Γ(0) = 0, which means a lack of any surfactant molecule adsorbed on the surface at the beginning of the diffusion process.…”

Section: Diffusion Coefficientsmentioning

confidence: 99%

Adsorption Properties and Wettability of Ethoxy- and Propoxy- Derivatives of 2-Ethylhexanol as Sterically Specific Surfactant Structures

Hreczuch,

Konopczyńska,

Stasiak

et al. 2024

Molecules

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2-ethylhexanol, an oxo alcohol competitively priced on the global market, has not been explored intensively as a raw material for surfactants, due to its weak hydrophobic character. However, its sequenced propoxylation and ethoxylation yield an innovative amphiphilic structure, which exhibits unique interfacial activity. The paper presents the differences in the fractional composition of innovative surfactants derived from 2-EH alcohol prepared using alkali and dimetalcyanide catalysts, as well as examples of excellent adsorption and interfacial properties of the latter. The adsorption behavior of the synthesized compounds was explored using equilibrium surface tension (the du Noüy ring method), dynamic surface tension (the maximum gas bubble pressure method) and static/dynamic contact angle (the sessile drop method). The results from the adsorption tests conducted at the air/aqueous surfactant solution interface underwent comprehensive qualitative and quantitative analyses. Moreover, based on the experimentally obtained dynamic surface tension isotherms and the developed algorithm, the diffusion coefficients for these preparations were estimated, and it was shown that the diffusivity of these surfactants is higher compared to the commercial formulations. The study’s outcomes in the testing of wettability indicate that new synthesized nonionic and anionic surfactants constitute an interesting group of amphiphiles with a wide application potential as effective wetting agents, especially in relation to the polymer surface. It should therefore be emphasized that the innovative surfactants described in this article, derived from 2-EH alcohol and prepared using dimetalcyanide catalysts, can successfully compete with conventional preparations such as ABS (Dodecylbenzenesulfonic Acid) or AES (Alcohol Ethoxysulphate) acid salts.

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Section: Diffusion Coefficientsmentioning

confidence: 99%