Molecular conformation of rigid cyclic and branched polymers in solution

Local conformational properties of rigid cyclic and branched polymers are not always the same as those for the corresponding linear chain unlike flexible polymers. We recently investigated rigid cyclic amylose derivatives and 3-arm star poly(quinoxaline-2,3-diyl) to determine their molecular conformation and intermolecular interactions in dilute solution. We found that local helical structure for the cyclic polymers are appreciably extended and therefore the main chain is more flexible than that for the corresponding linear chain. Regarding with this, the chiral separation columns made of the cyclic amylose derivative are substantially different separation behavior from those for the linear chain, indicating that the local conformation plays an important role for the molecular recognition ability. Both the linear and star chains have lyotropic liquid crystallinity. The phase diagram of isotropic and nematic phases are explained by a modified scaled particle theory when we assume some specific conformation in the nematic phase.