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Colloid and Polymer Science

, Volume 291, Issue 12, pp 2879–2892

First Online: 07 August 2013Received: 22 April 2013Revised: 06 June 2013Accepted: 07 June 2013

Abstract

The properties of a dendronized linear polymer DP in dilute solutions depending on solvent quality and temperature are described. The polymer has a contour length of Lc = 1,060 nm. The sample of the fourth generation PG4 was analyzed in the thermodynamically good solvents dioxane, chloroform, and methanol. The wormlike macromolecule has a persistence length lp = 7 nm in dioxane and a cross-section radius determined by small angle X-ray scattering SAXS of Rc SAXS = 2.8 nm. The bulk density of PG4 determined by SAXS was compared with solution density. Evidence for substantial swelling of the cross-section was found. Toluene acts as a thermodynamically poor solvent θ solvent. Above the θ temperature Tθ, a strong temperature dependence of the size and the Young’s modulus E was observed. Following Odijk, E-kBT ∼1 was found. Below Tθ, a regime characterized by unswelling of the wormlike chains was observed. The results suggest that DPs can be described as soft colloid filaments, which are subject to commonly observed interactions in colloidal systems. A phase diagram indicates a regime below Tθ in which fluctuations of osmotic pressure inside the filaments result in periodic undulation of the chains. In summary, introducing a dense dendritic shell around the backbone converts conventional polymers into molecular colloids.

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KeywordsDendronized polymers Solution behavior Phase separation Colloidal filaments Morphological instability Electronic supplementary materialThe online version of this article doi:10.1007-s00396-013-3007-9 contains supplementary material, which is available to authorized users.

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Author: Anja Kroeger - Baozhong Zhang - Christine Rosenauer - A. Dieter Schlüter - Gerhard Wegner

Source: https://link.springer.com/







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