Dilational surface elasticity of monolayers of charged polystyrene nano- and microparticles at liquid/fluid interfaces

Measurements of the dilational dynamic surface elasticity allow determination of some distinctions between the properties of monolayers of charged polystyrene nano- and microparticles at the water/air and water/oil interfaces. For example, the surface elasticity at the water/oil interface is lower and does not depend on the solution's ionic strength unlike the case of water/air interface. The obtained results at relatively low surface pressures (<15 mN/m) and homogeneous surface compression agree with a recent theory taking into account the residual charges at the particle/oil interfaces. At higher surface pressures, the behavior has some similarities with the properties of the monolayers of silica nanoparticles but differs strongly from the behavior of monolayers of soft microgel particles. (C) 2015 Elsevier B.V. All rights reserved.