  Polymer chains immersed in different solvent molecules exhibit diverse
properties due to multiple spatiotemporal scales and complex interactions.
Using molecular dynamics simulations, we study the conformational and static
properties of tagged chains in different solvent molecules. Two types of
solvent molecules were examined: one type consisted of chain molecules
connected by bonds, while the other type consisted of individual bead molecules
without any bonds. The only difference between the two solvent molecules lay in
the chain connectivity. Our results show a compression of the tagged chains
with the addition of bead or chain molecules. Chain molecule confinement
induces a stronger compression compared to bead molecule confinement. In chain
solvent molecules, the tagged chain's radius of gyration reached a minimum at a
monomer volume fraction of $\sim0.3$. Notably, the probability distributions of
chain size remain unchanged at different solvent densities, irrespective of
whether the solvent consists of beads or polymers. Furthermore, as solvent
density increases, a crossover from a unimodal to a bimodal distribution of
bond angles is observed, indicating the presence of both compressed and
expanded regions within the chain. The effective monomer-solvent interaction is
obtained by calculating the partial radial distribution function and the
potential of the mean force. In chain solvent, the correlation hole effect
results in a reduced number of nearest neighbors around tagged monomers
compared to bead solvents. The calculation of pore size distribution reveals
that the solvent nonhomogeneity induced by chain connectivity leads to a
broader distribution of pore sizes and larger pore dimensions at low volume
fractions. These findings provide a deeper understanding of the conformational
behavior of polymer chains in different solvent environments.
