Dendronised linear polymers

Fig. 2.16 Synthesis of dendronised linear polymers by the graft-to method (schematic)...

The macromonomer route assures uniform distribution of dendrons along the polymer backbone. Acrylates and styrenes with pendant dendrons proved to be well suited for polymerisation [57]. However, steric hindrance between monomers bearing higher-generation dendrons and the spatial requirements of the end of the chain cause problems The monomer reacts with the chain end only in the case of slight, if any, steric hindrance. Thus the method only provides access to dendronised linear polymers with relatively low molar masses... 

To summarise, a common feature of all methods for the preparation of dendronised linear polymers is the change of shape of a formerly flexible filamentary molecule by attachment of dendrons to the backbone of the polymer. As the extent of dendronisation increases, the coil structure extends and acquires greater rigidity, until the polymer assumes a linear extended form with a stiffened backbone. Stiffening of the polymer molecules to this extent has hitherto only been accom-... 

The dimensions of the dendritic cylinder depend on the one hand upon the degree of polymerisation, which determines the length, and on the other hand upon the generation of the dendron, which determines the diameter (about twice the size of the attached dendron). Conventional polymers have diameters in the Angstrom range, whereas the dendronised linear polymers described here have nanometre diameters. 

Chapters 2 and 3 have already introduced the reader to the general principles of the architecture, synthesis, and functionalisation of dendritic molecules - including hyperbranched and dendronised (linear) polymers (denpols). This chapter will now consider specific molecular scaffolds and syntheses of important types of dendrimers and their individual properties. More specialised and appli-cations-relevant properties of particular dendrimers are compiled in Chapter 8. 

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