Densely Packed Multicyclic Polymers.

Highly dense polymer chains were formed through coupling cyclic polymeric units in a sequence controlled manner. It was found that as the number of cyclic units increased the compactness substantially increased in a good solvent to a limiting value after only 12 units. This limiting value was close to that of a linear polymer chain in a θ solvent, in which polymer segment interactions with solvent are minimized. This remarkable result suggests that the unique architecture of the cyclic structure plays an important role to significantly change the polymer conformation and remain soluble in solution, which circumvents the need for cross-linking. The insight found in this work provides a physical mechanism as to why Nature uses cyclic structures in proteins to confer stability and the compacting of DNA strands to induce chromosome territories.