Abstract
The author considers the dynamics of a polydisperse sol made of randomly branched polymers near the gelation threshold. Assuming that the distribution is that of percolation, the author reviews various possible hydrodynamic interactions, namely the Rouse limit, where no backflow is present, and the Zimm limit, where hydrodynamic interactions are present. In the latter case, the author recovers a conjecture by Kertesz (1983) for the divergence of the viscosity. In the former case, the author recovers the de Gennes-Stephen result (1978). The author discusses the viscoelastic behaviour at short timescales.