Phase behaviors of dendrimer/solvent systems: Molecular thermodynamics approach

Abstract

Computer simulation study of the global phase behavior of linear rigid Lennard-Jones chain molecules: Comparison with flexible models Critical lines and phase coexistence of polymer solutions: A quantitative comparison between Wertheim's thermodynamic perturbation theory and computer simulationsWe investigate vapor-liquid equilibria of dendrimer/solvent ͑benzyl ether dendrimer/toluene͒ systems by the combination of incompressible lattice cluster theory and atomistic simulation technique. We also examine the structure effect of dendritic polymer and the specific interaction due to the difference of interaction energies of endgroup at the periphery of dendrimer molecules. The interaction energy parameters are obtained by the pairs method including Monte Carlo simulation technique with excluded volume constraint. In the pairs method, we do not simulate the whole molecule as in molecular dynamics or molecular mechanics, but only monomer segments interacting with solvent molecules. In general, those parameters are determined by fitting experimental data. Our results show that the specific interactions between the endgroup and the solvent molecule play an important role in determining phase behaviors of the given systems.

Dendrimers in Solution: Insight from Theory and Simulation

“…Fluid–fluid equilibria triggered by a worsening of the solvent quality is also a phenomenon that can be described by means of an appropriately defined effective interaction, in which the temperature‐dependent excluded volume parameter υ reflects the solvent effects. Although this line of research has not been followed up to now, an alternative, lattice‐cluster theory111, 112 has already led to predictions of dendrimer/solvent demixing that are in good agreement with experimental data.…”

Characterization of stationary phases by a linear solvation energy relationship utilizing supercritical fluid chromatography

“…Dabei werden die Lösungsmitteleigenschaften durch den temperaturabhängigen Parameter υ für den Volumenausschluss berücksichtigt. Die Lattice‐Cluster‐Theorie111, 112 lieferte Vorhersagen über die Entmischung von Dendrimeren und Lösungsmitteln, die gut mit experimentellen Daten übereinstimmen. Dieser Alternativansatz ist allerdings bisher nicht weiter verfolgt worden.…”

Self-Organization in Dendrimer Polyelectrolytes

“…For instance, l B of water (with ε r ≃ 80) at room temperature is ∼7 Å, which is close to 2 in the units of our models. In the context of the DH approximation, as implied by eq 1, in actual experiments apart from temperature the relative strength of electrostatic interactions can be controlled either by changing the number density or the valency of the ions (e.g., by controlling the charging level of the dendrimer and the salt concentration − ) or through modification of the Bjerrum length by selecting solvents which bare relatively high or low dielectric permittivities. − In this work, it was chosen that the number densities and the charge of the ions remain constant, while changes in the strength of electrostatic interactions were introduced by means of a systematic variation of l B . The values of Bjerrum lengths examined ranged from 0.5 to 150 (in units of σ), which would correspond to a variation of κ -1 between 0.74 and 0.04 σ in the context of the DH theory for the examined models.…”