Assessing the Solution Shape and Size of Charged Dendronized Polymers Using Double Electron-Electron Resonance

We present double electron electron resonance (DEER) data that suggest that highly branched dendronized polymers (denpols) in solution are macromolecules with persistent shape, a well-defined envelope, and a size independent of their environment. By determining the distance distribution of self-assembled dianionic spin probes (Fremy's salt dianion) on the surface of the cylindrically shaped and cationic denpols, we show that the measured solution radii are in good agreement with the solid-state radii of the neutral denpol analogues. An analytic distance distribution of particles on the lateral surface of cylinders is developed for this purpose and fitted to DEER time traces. Such, DEER in combination with site-directed spin probing provides an indirect and simple method to determine the solution shape and size of macromolecules on the nanometer scale. It furthermore shows that at least generation four and three denpols in solution may already be described as molecular objects.