文摘
By using a combination of experimental and theoretical tools, we elucidate unique physical characteristics of supramolecular triarylamine nanowires (STANWs), their packed structure, as well as the entire kinetics of the associated radical-controlled supramolecular polymerization process. AFM, small-angle X-ray scattering, and all-atomic computer modeling reveal the two-columnar 鈥渟nowflake鈥?internal structure of the fibers involving the 蟺-stacking of triarylamines with alternating handedness. The polymerization process and the kinetics of triarylammonium radicals formation and decay are studied by UV鈥搗is spectroscopy, nuclear magnetic resonance and electronic paramagnetic resonance. We fully describe these experimental data with theoretical models demonstrating that the supramolecular self-assembly starts by the production of radicals that are required for nucleation of double-columnar fibrils followed by their growth in double-strand filaments. We also elucidate nontrivial kinetics of this self-assembly process revealing sigmoid time dependency and complex self-replicating behavior. The hierarchical approach and other ideas proposed here provide a general tool to study kinetics in a large number of self-assembling fibrillar systems.
Keywords:
supramolecular polymers; fibrils; self-replication; triarylamines; light-triggered self-assembly