화학공학소재연구정보센터
Macromolecules, Vol.51, No.16, 6421-6429, 2018
Influence of the Sequence in Conjugated Triblock Copolymers on Their Aggregation Behavior
Conjugated diblock copolymers can exhibit very promising properties, often based on microphase separation. However, both blocks can influence each other's aggregation behavior, which might lead to a suboptimal aggregation behavior of the consecutive blocks. Herein, we investigate whether the introduction of a third, nonaggregating block can render triblock copolymers where the two blocks do not influence the aggregation behavior of one another. Different triblock copolymers consisting of solely thiophene units as well as triblock copolymers containing selenophene and (a)chiral thiophene units were designed to investigate the influence of the sequence of the blocks, the initiating unit, and the nonaggregating block on the aggregation behavior of the resulting triblock copolymers. The conjugated triblock copolymers were synthesized via a controlled Kumada catalyst transfer condensative polymerization (KCTCP), and their aggregation behavior was investigated via UV-vis and circular dichroism (CD) spectroscopy. For all synthesized polymers it was observed that when two aggregating blocks are separated from each other by a nonaggregating block, they do not influence each other's aggregation behavior and aggregate separately. However, when the two aggregating blocks are situated next to each other, they influence each other's aggregation behavior strongly and aggregate as one block.