We perform molecular simulations to study the swelling of a model network in contact with different chain-like solvents. The method is Gibbs-ensemble molecular dynamics, which is a molecular dynamics implementation of the concept underlying the Gibbs-ensemble Monte Carlo method. We simulate swelling isotherms for three coarse-grained solvents with one (S-1), six (S-6), and twelve (S-12) centers in the high pressure regime at supercritical temperatures. The simulated swelling isotherms of the S-1-solvent exhibit a maximum near the critical pressure which decreases and shifts towards higher pressures with increasing temperature. Based on a modified Flory-Huggins approach, a set of numerically soluble equations is derived in order to reproduce the simulated isotherms. The resulting theoretical isotherms are in very good qualitative agreement with the simulations. Comparison of the different solvents shows also that the swelling ratio decreases when the chain length of the solvent increases. (C) 2000 American Institute of Physics. [S0021-9606(00)50111-1].