An Alternating Copolymer of a Tetrapeptide and a Tetrathiophene Prepared by a Click Reaction: A Study of the Synthesis and Assembly Behavior

Alternating copolymers of an oligopeptide (N-3-GVGV-N-3, where G: glycine; V: valine) and an oligothiophene (5,5'-bis(ethynyl)-3,3'-dioctyltetrathiophene) are prepared by click chemistry. The experimental results discover that these copolymers exhibit strong molecular-weight-dependent self-assembly behaviors. The copolymer P1 with the lowest weight-average molecular weight ((M) over bar (w) = 7400 g mol(-1)), assembles into well-ordered fibrous nanostructures. P3 ((M) over bar (w) = 16 980 g mol(-1)) assembles into nanoballs. P2, which has the medium (M) over bar (w) between P1 and P3, ((M) over bar (w) = 14 800 g mol(-1)), exhibits more-complicated self-assembly behaviors, more like a transition state between the other two. All of the results suggest the self-assembly ability of these oligopeptide segments might be the major reason for the nano-structure evolution.