Excluded volume effect in flexible dendrimer systems: A self-consistent field theory

TL;DR

This study employs a self-consistent field theory to analyze the conformational and scaling behaviors of flexible dendrimers in good solvents, confirming the dense-core model and deriving specific scaling laws for their size.

Contribution

It introduces a combined self-consistent field and excluded volume potential approach to accurately model dendrimer conformations and scaling laws, supporting the dense-core hypothesis.

Findings

Dendrimer conformation is strongly stretched at the dense core.

Segment density profile exhibits a shoulder shape in outer regions.

Derived scaling law: R proportional to (GP)^0.2 N^0.4, or P^0.6 when G is fixed.

Abstract

We have studied the conformational and scaling behaviors of a flexible dendrimer immersed in athermal or good solvents. A self-consistent field theory combined with a pre-averaged excluded volume potential representing the two-body short-ranged interaction between the segments, was adopted to calculate the density profile of various generations and branch points thoroughly. Our calculation results support the "dense-core" model. We find the conformation of the dendrimer is strongly stretched in the dense central region, but much weakly stretched in the outer region where the segment density profile is shoulder shaped. Both our self-consistent field theory calculation and the Flory mean-field theory calculation give the same scaling law R proportional to (GP)^0.2N^0.4, where G is the generation number of the dendrimer, P is the spacer segment number, and N is the total segment number. If we fix G, the scaling law is simplified to R proportional to P^0.6 in good solvent.