Spreading of liquids on gel surfaces

In this work we present a simple model for the kinetics of spreading of film-forming liquids on polymer gels. The model is compared with experiments and fair agreement is obtained. The spreading process can be theorized by considering the gel as a thick liquid layer containing a fibrous material (i.e., the polymer network). The spreading theory of Joos and Pintens is extended in such a way that the penetration of the flow into the bulk of the gel—which plays the major role in the kinetics of the spreading—is described by the Debye–Brinkman equation. It is also shown that spreading experiments can provide information on the surface structure of the underlying gel.