Self-Assembly of Unconventional Triphenylene-Based Frustrated Amphiphile in Solution

Unconventional amphiphilic molecules having a rigid hydrophobic central unit and flexible or semiflexible hydrophilic chains on the rim have proven valuable in several technological applications, for example, host-guest chemistry. The further presence of alternating hydrophobic and hydrophilic tails complicates the definition of clear core and shell regions, resulting in complex segregation and frustrated self-assembly. In this study, we investigate symmetric triphenylene-based amphiphilic derivatives with alternating benzyl and alkylsulfonate groups. We characterize their self-assembly in water and different solutions using several experimental techniques, including NMR, atomic force microscopy, dynamic light scattering, and small-angle X-ray and neutron scattering, alongside extensive molecular dynamics simulations, including both atomistic and coarse-grained integrative modeling with metainference. In aqueous solutions, these amphiphiles form stacked assemblies, adopting alternate up-down conformations driven by pi-stacking of up to six molecules. The introduction of NaCl salt screens unfavorable electrostatic interactions, thus promoting further pi-stacking and leading to the formation of larger elongated aggregates.