title: Accurate coarse-grained models for mixtures of colloids and linear polymers under good-solvent conditions.
abstract: A coarse-graining strategy, previously developed for polymer solutions, is extended here to mixtures of linear polymers and hard-sphere colloids. In this approach, groups of monomers are mapped onto a single pseudoatom (a blob) and the effective blob-blob interactions are obtained by requiring the model to reproduce some large-scale structural properties in the zero-density limit. We show that an accurate parametrization of the polymer-colloid interactions is obtained by simply introducing pair potentials between blobs and colloids. For the coarse-grained (CG) model in which polymers are modelled as four-blob chains (tetramers), the pair potentials are determined by means of the iterative Boltzmann inversion scheme, taking full-monomer (FM) pair correlation functions at zero-density as targets. For a larger number n of blobs, pair potentials are determined by using a simple transferability assumption based on the polymer self-similarity. We validate the model by comparing its predictions with full-monomer results for the interfacial properties of polymer solutions in the presence of a single colloid and for thermodynamic and structural properties in the homogeneous phase at finite polymer and colloid density. The tetramer model is quite accurate for q ≲ 1 (q=Rg/Rc, where Rg is the zero-density polymer radius of gyration and Rc is the colloid radius) and reasonably good also for q = 2. For q = 2, an accurate coarse-grained description is obtained by using the n = 10 blob model. We also compare our results with those obtained by using single-blob models with state-dependent potentials.
authors.affiliation: SISSA, V. Bonomea 265, I-34136 Trieste, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: D'Adamo
authors.affiliation: Dipartimento di Fisica, Sapienza Università di Roma and INFN, Sezione di Roma I, P.le Aldo Moro 2, I-00185 Roma, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Pelissetto
authors.affiliation: Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila and CNISM, UdR dell'Aquila, V. Vetoio 10, Loc. Coppito, I-67100 L'Aquila, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Pierleoni