Monomeric copolymers helical conformation

A similar effect sometimes occurs with copolymers of chiral and nonchiral monomeric units, whereby their optical activity is higher than the additivity rule allows. The nonchiral monomeric units are obviously drawn into helical conformations by the helical sequences of the chiral monomeric units. 

Type 1 Homopolymers An and Bm have a similar erystal strueture, with suffieiently small differences in imit eell dimensions. Binary systems, whether copolymers or homopolymer mixtures, display the same structure at any intermediate eomposition, exeept for a continuous change in eell dimensions (isomorphism in a true sense). The homopolymer ehains may possess helical conformations with slightly different ratios of monomeric units per helix piteh, in whieh ease intermediate helix conformations should appear at intermediate compositions. 

Copolymers consisting of alternatively arranged monomeric units of opposite chirality are optically inactive as a result of the configuration itself. They can, however, produce helices of a specific direction of turn in certain solvents, such that this preferential conformation produces an optical activity. Poly(L-alt-D-leucine), which produces what is known as a tt helix in benzene, is an example of this. 

As for polyelectrolytes the Bernouillian statistics should not be suitable to represent the distribution of ionized and non-ionized units, since the influence of charges in place probably orients the addition of new charges during neutralization. On the contrary. Equation (4) should be valuable for rigid and helical copolymers since the main chain conformation would not change with the composition. The non-linearity would be only due to variations in the monomeric unit interactions according to the composition and the monomeric unit distribution along the macromolecule. 

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