Surface tension behavior of superspreading and non-superspreading trisiloxane surfactants

One parameter frequently considered to be relevant for superspreading of trisiloxane surfactants is surface tension kinetics. In the scientific literature, some experimental results reported for trisiloxane surfactants are in contradiction with fundamental concepts of surfactant monomer diffusion. Therefore, maximum bubble pressure tensiometry has been used to determine dynamic surface tension (DST) of two types of trisiloxane surfactants: superspreader and non-superspreader. Results show that both surfactants behave similarly at concentrations below critical micelle concentration (CMC), as expected. The CMC curves, as determined by drop shape analysis, confirmed that the more hydrophilic non-superspreader has a higher CMC as compared to the more hydrophobic superspreader. Accordingly, the lower surfactant monomer concentration of the superspreader results in a higher DST than the non-superspreader at the same surface age. So, in contrary to claims in the literature, there is nothing mysterious or unexpected concerning the surface tension behavior of trisiloxane surfactants.

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Adsorption of Dispersions of Silica Nanoparticles and anAmphiphilic Triblock Copolymer at Water‐Vapor Interface

This study is about the surface modification of hydrophilic silica nanoparticles by
non-chemical adsorption of an amphiphilic triblock copolymer (Pluronic F-127)
and its influence on surface tension and interfacial rheology. As copolymer
concentration increases, we observed an increment of the hydrodynamic diameter
and a reduction of the effective charge of the complexes. The presence of silica, at
low Pluronic F-127 concentration, increases surface tension and affects the
rheology: those results suggest that silica particles hinder Pluronic F-127
molecules reorganization at the interface, with subsequent increase in foam