Third-generation cylindrical dendrimers based on L-aspargic acid in solutions: hydrodynamic and electrooptical properties

TL;DR

This study investigates the hydrodynamic and electrooptical properties of third-generation cylindrical dendrimers based on L-aspargic acid, revealing their reorientation mechanisms and solvent-dependent behavior.

Contribution

It provides new insights into the properties of third-generation dendrimers and how their reorientation mechanisms vary with solvent type and molecular structure.

Findings

Higher birefringence constants than lower-generation dendrimers.

Reorientation mechanism depends on solvent properties.

Terminal substituents are mainly oriented along the primary chain.

Abstract

Samples of third-generation cylindrical dendrimers with molar masses ranging in the interval 20000...60000 have been studied by the methods of equilibrium and non-equilibrium electrical birefringence, molecular hydrodynamics and optics. It was found that the absolute values of Kerr and flow birefringence constants exceed the values obtained for analogous dendrimers of lower generations. The mechanism of reorientation has proven to be strongly dependent on the physical and chemical properties of the solvent. In chloroform solutions, the studied dendrimers align to the microwave-frequency electric fields according to large-scale mechanism. In dichloroacetic acid solutions, the observed reorientation mechanism is low-scale, which is explained by degradation of intermolecular hydrogen bonds. Terminal dendritic substituents of the macromolecules have experimentally proven to be oriented mainly along the primary polymer chain.