Interfacial tension and a volume phase transition of microgel particles

A continuous volume phase transition of 2-vynilpyridyne microgel particles is described, both experimental and theoretically. The network charge was s elected as the physical variable triggering the transition, which was follo wed by dynamic light scattering. The interpretation of the results with the Flory-Huggins thermodynamic model for gels suggests the consideration of e ffects leading to a new osmotic equilibrium. In previous works ion condensa tion was introduced to account for the unusual behaviour yielding interesti ng but not totally successful results. In the present paper, an alternative explanation based on an interfacial tension contribution to the total osmo tic pressure is presented.