caa a22 4500 475764870 CHVBK 20180406123602.0 cr unu---uuuuu 170329e20000201xx s 000 0 eng 10.1007/s003960050026 doi (NATIONALLICENCE)springer-10.1007/s003960050026 Small solid particles and liquid lenses at fluid/fluid interfaces [Elektronische Daten] [R. Aveyard, J. H. Clint, D. Nees] The behaviour of small solid particles and liquid droplets at fluid interfaces is of wide interest, in part because of the roles they play in the stability of foams and emulsions. Here we focus on solid particles at liquid interfaces, both singly and in highly structured monolayers. We briefly mention small oil lenses on water in connection with the determination of line tension, τ. Particles are surface-active in the sense that they often adhere quite strongly to liquid surfaces, although of course they are not usually amphiphilic. The three-phase contact line around a particle at an interface is associated with an excess free energy resulting in a tendency of the line to contract (positive τ, which is a 1D analogue of surface tension) or to expand (negative τ). Positive line tension acts so as to push the contact angle of a particle with the fluid interface further away from 90°, i.e. to force the particle towards the more "wetting” of the two bulk phases. It also leads to activation barriers to entry and departure of particles from an interface. The behaviour of particle monolayers at octane/water interfaces is also discussed . It is found that, for monodisperse spherical polystyrene particles containing ionisable sulphate groups at the surface, highly ordered monolayers are formed. This appears to result from very long range electrostatic repulsion mediated through the oil phase. Surface pressure-surface area isotherms are discussed for particle monolayers and it is shown, using light microscopy, that at monolayer "collapse” particles are not expelled from the monolayers but rather the monolayer folds, remaining intact. This has an important bearing on methods, involving the use of the Langmuir trough, for the experimental determination of contact angles and line tensions in particulate systems. Springer-Verlag Berlin Heidelberg, 2000 Key words Line tension nationallicence Liquid lenses nationallicence Particles at interfaces nationallicence Particle monolayer structure nationallicence Wettability nationallicence Aveyard R. Department of Chemistry, The University of Hull, Hull HU6 7RX, UK e-mail: r.aveyard@chem.hull.ac.uk Tel.: +44-1482-465218 Fax: +44-1482-466410, GB aut Clint J. H. Department of Chemistry, The University of Hull, Hull HU6 7RX, UK e-mail: r.aveyard@chem.hull.ac.uk Tel.: +44-1482-465218 Fax: +44-1482-466410, GB aut Nees D. Central Laser Facility, Rutherford Appleton Laboratory Didcot OX11 0QX, UK, GB aut https://doi.org/10.1007/s003960050026 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s003960050026 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Aveyard R. Department of Chemistry, The University of Hull, Hull HU6 7RX, UK e-mail: r.aveyard@chem.hull.ac.uk Tel.: +44-1482-465218 Fax: +44-1482-466410, GB aut NATIONALLICENCE 700 1- Clint J. H. Department of Chemistry, The University of Hull, Hull HU6 7RX, UK e-mail: r.aveyard@chem.hull.ac.uk Tel.: +44-1482-465218 Fax: +44-1482-466410, GB aut NATIONALLICENCE 700 1- Nees D. Central Laser Facility, Rutherford Appleton Laboratory Didcot OX11 0QX, UK, GB aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer