Solution processable polydiacetylene architectures via macromolecular self-assembly.

摘要

pi-Conjugated (semiconducting) polymers are highly promising materials for applications in various types of electronic devices. A major challenge in this field is to develop ordered, yet easy to process, molecular systems. Polydiacetylene (PDA) is a promising candidate in this regard due to its electronic properties and synthetically accessible monomer units. In this work, we examined the use of increasingly complex molecular self-assembly processes for the creation of structurally complex (one and two dimensional) pi-conjugated polymer assemblies. "Laterally directed" molecular assembly motifs were explored for the formation of "2-D" (two-dimensional) self-assembled monolayers (SAMs). For "1-D" (one-dimensional) structures, hydrogen bonding and homochirality were studied as the means to precisely pre-position diacetylene monomers along a helical polyisocyanide backbone to form solution-processable polydiacetylene "nanowires." Through specific monomer design, we were able to identify two self-assembly motifs that led to the formation of "red" and "blue" phase "2-D" SAMs. This confirmed that increased organization/stability with added flexibility within the backbone of the molecule is essential for the formation of stable and ordered PDA structures. For "1-D" structures, synthesis and polymerization of isocyanide compounds led to the formation of "yellow" phase materials. Increased flexibility with added hydrogen-bonding motifs facilitated the formation of highly ordered solution-processable polydiacetylene "nanowires."