Sphere‐Like Fourth Generation Pseudo‐Dendrimers with a Hyperbranched Core

Abstract

A pseudo-dendritic structure clear of linear units is obtained from a hyperbranched aliphatic-aromatic polyester core modified by a B-protected AB(2) monomer. The chosen sequence of reaction and deprotection steps yields four generations of pseudo-dendrimers with either silyl- or OH-terminal units. (1)H and (13)C NMR confirm the extent of modification and the degree of branching in the different generations. The influence of generation number, end group type, and degree of branching on the specific solution behavior of the pseudo-dendrimers is investigated by size-exclusion chromatography coupled to static light scattering and by intrinsic viscosity characterization. Apparent density and scaling parameters indicate increased compactness of the pseudo-dendrimers with increasing generation number.

Dendronized Hyperbranched Macromolecules: Soft Matter with a Novel Type of Segmental Distribution

“…Even in the first generation the pseudo‐dendrimers have high molar masses and an end group number of 100, which increases to 800 in the fourth generation (with a degree of polymerization of around 50 for the hb core). Surprisingly, we observed the characteristic rheology behavior for dendrimers right after the first modification, that is, in G1 6. These findings show that pseudo‐dendrimers could be an interesting alternative to dendrimers in applications where higher generations come into play.…”

“…The analysis was performed without any staining so as to evaluate the contrast only on the basis of the particle density. The size of a single particle is not representative for the whole sample, which is characterized by molar mass distribution of 1.7–1.9 in all three examples 6…”

“…In this study the comparison of the properties of pseudo‐dendrimers and dendrimers is performed based on generation number to enable a correlation between synthetic steps and dendron distribution. The successful synthesis and modification of aliphatic‐aromatic hb‐polyesters has been described elsewhere 6. Polydispersities M w / M n <2 for all the structures enable data comparison and accurate analysis of the scaling properties.…”

“…Polydispersities M w / M n <2 for all the structures enable data comparison and accurate analysis of the scaling properties. Herein, we report on the global features of pseudo‐dendrimers of generation G1–G4, that is, the molar mass M w , radius of gyration R g , hydrodynamic radius R h , intrinsic viscosity [ η ],6 and inter‐particle interactions, for example, the second osmotic virial coefficient A 2 . Molecular dynamics (MD) simulation of the first three generations gives a complementary view on the shape of the polymers in solution and the density distribution in the molecular structure.…”

“… MD simulation of G0, G1, and G2 pseudo‐dendrimers with deprotected OH end‐groups6 with degree of polymerization (DP) of 92 of the G0 hb core in THF (solvent molecules are hidden). The Figure shows the full space‐filling models as well as the contribution of the post‐modification in G1 and G2 to the pseudo‐dendrimer formation.…”