Polymers Connected with Bivalent Hydrogen Bonds

Polymers Connected with Bivalent Hydrogen Bonds 

Bivalent hydrogen bonds are usually stronger than their monovalent coim-terparts, and therefore the impact of a few hydrogen bonds on the resulting material properties is more pronounced. 

The amidic bonds within amino acids can be also used to effect the organization of polymers into superstructures (Fig. 10). Thus, the formation of artificial helices on the basis of assembling polymers has been described by use of poly(acetylenes) bearing pendant L-valine side-chains. [71,72] Two effects are important for the association of these ladder-type polymers into double-stranded helices (a) the reduction of conformational freedom by the poly(acetylene) chain with respect to a conventional alkyl-chain and (b) the selective association of the L-valine residues by specific hydrogen bonding. An AFM image of the associates on a fiat surface demonstrates the presence of a string-pearl structure reminiscent of natural DNA. 

Carboxylic acids are highly efficient hydrogen-bonding systems for the formation of ordered supramolecular aggregates. Sleiman et al. [74] investigated 

The use of simple benzoic acids for the self assembly of polymers has been investigated by Bouteiller et al. [76-78] in a series of papers (Fig. 13). They used telechelic poly(dimethylsiloxane)s with a molecular weight of 

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Polymers Connected with Bivalent Hydrogen Bonds... 

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