Packing of macromolecules in oriented samples

Another reason why it is difficult to discuss the structural model of cholesterol-containing pol pers is the fact that so far no adequately substantiated structural model of low-molecular cholesteric liquid crystals exists, apart from the already mentioned packing pattern proposed in Ref. (26), It seems that for a full understanding of the mesophase structure of cholesterol esters, one should, first of all, carefully study their crystalline structure. Such a study, described in Refs, (27, 28), has not yet lead to a complete description of molecular packing in cholesterol esters. 

Although the structure of cholesterol-containing polsrmers is not yet completely understood, there is no doubt that the liquid crystalline properties exhibited by these polymers are due to a particular oirder in the arrangement of cholesterol groups. This is corroborated by the results of studying the structure and optical properties of model compounds not containing cholesterol. The above-mentioned PMAA-n and PMMAA-n are optically isotropic in all three physical states vitrified, elastic and viscous. 

36 %) corresponding in magnitude to the branch length. At temperatures above the melting point, the polymer is optically isotropic. 

We have already considered the structure and properties of polymers containing cholesterol in such monomer unit. It is also of interest to examine the structure and properties of polymers in which the content of cholesterol groups can be varied, i,e, copolymers, Given in Table V are transition temperatures for some copolymers that we have synthesized. 

As can be seen from this table, the introduction of a second component, namely, a solvent of cholesterol-containing units, whereby the glass temperature is lowered, resulted, in some cases, in a longer interval of existence of the elastic and viscous liquid-crystalline states, while in other cases, in the formation of optically isotropic polymers. 

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