Nonionic surface-active compounds. VII. Interfacial tensions of solutions of nonionic surface-active agents

Significance of glass transition temperature to polymer latex stabilisation by nonionic surfactants

“…In view of Becher's [1] oil/water interracial tension measurements, from which he deduced in effect that the degree of penetration depends on the hydrophobicity of the surfactant, a further temperature effect might be expected with nonionic surfactants at the oil/water interface in addition to that observed here at the melting point of the disperse phase. We would anticipate not only a reduction in adsorbed layer thickness arising from penetration of the oil/ water interface by the stabilising surfactant but also a reduction from the ongoing tendency of the dehydrating surfactant to sink still deeper into the oil phase as temperature increases further.…”

“…This assumption however is not expected to have quantitative validity for sterically stabilised dispersions/emulsions. Here the stabilising polymer or surfactant may penetrate the liquid/liquid interface of an emulsion drop which it can not do at the solid/ liquid interface [1,2]. For this reason the adsorption properties and colloid stabilising ability of a given polymer or surfactant may differ depending on whether the substrate is in solid or liquid state.…”

Silicon-modified carbohydrate surfactants. IV. The impact of substructures on the wetting behaviour of siloxanyl-modified carbohydrate surfactants on low-energy surfaces

“…For the n-octane/oxethylated lauryl alcohol system Becher 33 found that ␥ Despite the deviations stated, and the fact that nonidentical values for the solid surface tension of nonpolar solids and the Lifshitz-van der Waals contribution to surfactant surface tension yield an interfacial tension contribution (see Eqn [13]), Becher 33 assumed that ␥ sl almost exclusively stems from the polar contribution of the EO chains in the water phase.…”

“…29 But they cannot suppress a certain depth influence of the oxygen atoms. If one considers both (1) the differences in the specific area per molecule [(with similar packing at both interfaces, 33 at the liquid/vapour interface 40 Å 2 (22) 26 and 50 Å 2 (3) 26,27 ] and (2) in (22) the significantly greater distance to the solid surface of the second oxygen atom (Fig. 12, right-hand diagram), an effective reduction of the polarity for 22 can be assumed.…”

Influência do grau de etoxilação no comportamento de álcoois secunários etoxilados

“…A existência de um ponto mínimo da tensão superficial está de acordo com os rebotados descritos por Becher (1963) e Hansen e Fagerheim (1998).…”