Conformations of Highly Charged Dendronized Polymers in Aqueous Solutions of Varying Ionic Strength

Abstract

Conformations of two linear, charged dendronized polymers in aqueous solutions of different ionic strengths have been studied by light scattering. Both polymers have a polyacrylic core. The repeating unit of the first of the polymers studied contains a residue of aspartic acid bound to a carboxylic group of the core by an amide group as a first‐generation dendron, whereas the second polymer contains second‐generation dendrons constructed of three molecules of aspartic acid. The dendritic polymers adopt different conformations depending on the generation. Polymers with first‐generation dendrons are flexible and their conformation is sensitive to salt. The polymers with dendrons of the second generation adopt a semi‐flexible rod conformation. Their conformation is not sensitive to salt but is determined by the bulkiness of the dendrons.Polyacrylic polymers having a residue of aspartic acid as a first‐generation dendron (P1), and having a second‐generation dendron on the basis of aspartic acid (P2).magnified imagePolyacrylic polymers having a residue of aspartic acid as a first‐generation dendron (P1), and having a second‐generation dendron on the basis of aspartic acid (P2).

Large Mechanical Response of Single Dendronized Polymers Induced by Ionic Strength

“…The present finding is also in line with the known weak influence of the ionic strength on linear polyelectrolytes 10. 11 A similar transition between a flexible conformation for PG1 and a more rigid structure of PG2 was found by dynamic light scattering measurements 30. The increase of the elasticity constant with decreasing ionic strength probably originates from the high charge density of the polymers and an increasing importance of electrostatic interactions.…”

Helical chirality in dendronized polyarylacetylenes

“…18 A similar use of non-covalent association has been subsequently reported by others. 30,31 Self-organization, the spontaneous generation of periodic order under a given set of conditions, 32 reflects emergent complexity in supramolecular assemblies and enables their investigation via retrostructural analysis (Scheme 1). 4,10,11,[13][14][15][16][17][18]22,25,26,[33][34][35][36][37][38] Self-assembling dendrons are those fragments of a dendrimer capable of spontaneously forming well-defined supramolecular assemblies either in bulk or solution.…”

Synthesis and Conformations of Dendronized Poly(l-lysine)

“…For example, we have used them recently as catalysts in organic chemistry, as “molecular pixels” in imaging applications, and as carriers for drug delivery . The influence that dendrons can have on a polymer backbone has been explored by a number of groups, and while dendron side chains most notably affect a main chain's persistence length and rigidity, − other properties such as helicity − and extended conjugation lengths , for conjugated polymers can be imparted upon a polymer backbone.…”