Precision control via molecular structure over adaptive
conjugated
polymer properties in aqueous environments is critical for realizing
their biomedical applications. Here, we unravel the dependence of
amphiphilic peptide-polydiacetylene (PDA) conjugate properties on
the characteristic steric and hydrophobic contributions within peptide
segments that serve as a biomimetic template for diacetylene polymerization
in water. We investigated the functional impacts of molecular volume
and polarity changes brought by dipeptide substitution domains on
the following peptide-PDA material properties at multiple length scales:
supramolecular assembly behavior, chain conformation-dependent photophysical
properties, cell-material interfacing, and for the first time, bulk
electrical properties of their films processed in water. A library
of peptide-PDAs with systematically varied sequences show that the
contributions of steric effects predominantly influence the electronic
structure and resulting trends in photophysical properties, while
the interplay between size and hydrophobicity of individual residues
becomes more significant for higher-order assemblies affecting bulk
properties. This work demonstrates sequence-tunable molecular volume
and polarity as synthetic handles to rationally modulate PDA material
properties across length scales, providing insights into the programmability
of biomimetic conjugated polymers with adaptive functionalities.