  We propose a predictive Density Functional Theory (DFT) for the calculation
of solvation free energies. Our approach is based on a Helmholtz free-energy
functional that is consistent with the perturbed-chain SAFT (PC-SAFT) equation
of state. This allows a coarse-grained description of the solvent, based on an
inhomogeneous density of PC-SAFT segments. The solute, on the other hand, is
described in full detail by atomistic Lennard-Jones interaction sites. The
approach is entirely predictive, as it only takes the PC-SAFT parameters of the
solvent and the force-field parameters of the solute as input. No adjustable
parameters or empirical corrections are involved. The framework is applied to
study self-solvation of n-alkanes and to the calculation of residual chemical
potentials in binary solvent mixtures. Our DFT approach accurately predicts
solvation free energies of small molecular solutes in three different solvents.
Additionally, we show the calculated solvation free energies agree well with
those obtained by molecular dynamics simulations and with the residual chemical
potential calculated by the bulk PC-SAFT equation of state. We observe higher
deviations for the solvation free energy of systems with significant
solute-solvent Coulomb interactions.
