Macromolecules, Vol.30, No.21, 6650-6657, 1997
Structure and Thermodynamics of Homogeneous-Dendritic-Polymer Solutions - Computer-Simulation, Integral-Equation, and Lattice-Cluster Theory
We present some calculated structural and thermodynamic properties of homogeneous-dendritic-polymer solutions using computer simulation methods, integral-equation theory, and lattice-cluster theory. Monte-Carlo methods are used to sample conformations of polymer molecules. From these conformations, we first compute two properties of the polymer : the distribution of segments within the molecule and the radius of gyration. Simulations for nonattracting polymer pairs give the potential of mean force and the second virial coefficient. Given the potential of mean force between polymer molecules, we use integral-equation theory to calculate the equation of state of an athermal solution at low polymer concentrations. We apply lattice-cluster theory to obtain solvent activities and liquid-liquid equilibria for homogeneous-dendritic polymers in nonathermal concentrated solution. There is little difference between the vapor pressures of solutions of linear polymers and homogeneous-dendritic polymers. However, there is a modest difference between the liquid-liquid coexistence curve for linear-polymer solutions and homogeneous-dendrimer solutions. The critical temperatures of dendrimer solutions are lower than those of solutions containing corresponding linear polymers. This difference rises with increasing generation number and decreasing separator length.
Keywords:MONTE-CARLO SIMULATIONS;MONOMER STRUCTURE;STARBURST DENDRIMERS;BLENDS;COMPRESSIBILITY;CHEMISTRY;MOLECULES;TOPOLOGY;MICELLES;SHAPE