Simulation of Vertical Surfactant Distributions in Drying Latex Films

Abstract

Following our previous contribution ( Gromer, A. et al. Langmuir 2015 , 31 , 10983 - 10994 ) presenting a new simulation tool devoted to particle distributions in drying latex films, this Article describes the prediction of surfactant concentration profiles in the vertical direction during the complete film formation process. The simulation is inspired by cellular automata and equations by Routh and co-workers. It includes effects that were not considered before: surfactant convection by water and surfactant desorption upon particle deformation. It is based on five parameters describing the nature of the polymer/surfactant system and on film formation conditions. In particular, the viscoelastic properties of the polymer were taken into account through the λ̅ parameter introduced by Routh and Russel. Results show the importance of convection by water and the influence of the particular deformation mechanism on the final surfactant distribution. Excesses or depletions can be predicted either on the surface or on the substrate sides, in qualitative agreement with the numerous existing experimental studies. The complex interplay between parameters governing surfactant distributions makes the results unpredictable without the help of such a simulation tool. Therefore, it should be of interest to both industrial and academic scientists.

A critical and quantitative review of the stratification of particles during the drying of colloidal films

“…In follow-up work, they also considered the vertical distributions of surfactant using their cell model. 48 The distribution of colloidal particles in drying films has also been modelled using Monte Carlo simulations. 49 Large-scale molecular dynamics simulations 50 , which included solvent explicitly, have confirmed that nanoparticles accumulate at the liquid/vapour interface when the evaporation rate is relatively fast.…”

Characterization of Magnesium-Polylactic Acid Films Casted on Different Substrates and Doped with Diverse Amounts of CTAB

“…Regarding the vertical distribution of the surfactant in the film, its molecular structure must be taken into account. Gromer et al [ 22 ] stated that hydrophobic surfactants are distributed homogeneously throughout the film, while hydrophilic ones tend to accumulate at the air and substrate sides, leaving the bulk impoverished. Moreover, Zhang and Severtson [ 16 ] explained the differences in accumulation between the film–substrate and the film–air interfaces, only in the case of surfactants dissolved in water.…”

“…Similar results were found by many other researchers working with different surfactants, such as Fukuoka et al [ 19 ] or Gifu et al [ 20 ] among others [ 17 , 21 ]. However, Gromer et al [ 22 ], studying the surfactant distribution in films made from polymeric colloids, have shown that there are a large number of factors affecting the surfactant content along the film thickness, such as the type of surfactant and its initial concentration, the inorganic particles present, the size, shape, and thickness of the film, the aging conditions, and even the substrate on which the film is poured.…”

Influence of PVAc/PVA Hydrolysis on Additive Surface Activity

“…Successful formulation rests on the ability of the additive-polymer interactions to confer the desired properties and functionality to the end products. The partitioning, segregation, and release of those small molecules in polymers govern the processing, performance, and lifetime of many industrials products [1] and are affected by factors such as temperature [2], aging, additive nature [3,4], matrix deformation [5,6], and crystallinity [7]. The process of migration, its mechanisms, molecular interactions, and timescales [8] are still not very well understood except for highly simplified model systems.…”