Bottle brush molecules

Fig. 2. Schematic illustration of side-chain polymer crystals where (1) represents the polymer backbone, (2) represents the alkylene spacer and (3) represents the different side-group moieties. In a real polymer the backbone would not generally be in the rigid configuration shown. For example, with an SiO backbone the alkylene chains are attached to each Si atom (for a fully substituted system) and rotational isomerism due to free rotation about the linking oxygen would ensure a random backbone configuration. Typical spacer groups consist of between 4 and 12 methylene units and the side-group moieties contain several bulky phenylene units. Therefore, in three-dimensional space the molecules would look more like a bottle brush with random bristles attached to a flexible backbone stem.

FIGURE 11.6 Gum arabic monomer unit. The molecules are probably constructed like bottle brushes with a long core from which branch numerous side chains. 

Fig. 2. Selected architectures of block copolymers (a) diblock (b) triblock (c) comb copolymer consisting of flexible chains (d) rod-coil diblock copolymer consisting of a rodlike block and a coil-like block (e) hairyrods, i.e., comb-block copolymers consisting of rodlike backbone and coil-like side chains and (f) LC coil with a side-chain liquid crystalline (LC) block and a flexible block. Many other variations have been introduced, such as multiblock copolymers, block copolymers consisting of several rodlike blocks, or star-shaped block copolymers. Comb-coil block copolymers with dense packing of side chains are also denoted as molecular bottle brushes, as is illustrated in (g) by a simulated structure of an isolated molecule dissolved in a solvent. (Courtesy of Mika Saariaho.)...

Well-defined carbon stractures were also prepared from densely grafted bottle bmsh molecules with PAN di-(AB) and triblock-( ABC) copolymer SCs. Thin films of the SC brushes were prepared by drop casting aqueous solutions onto dean silicon wafer substrates. After thermal treatment, the SC brash precursors were converted into nanostractured carbon. AFM images of the resulting films revealed a sirrface with characteristic round protrusions and roughness of 4.0 nm. 

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