Bolalipid fiber aggregation can be modulated by the introduction of sulfur atoms into the spacer chains

► Symmetrical single-chain bolaamphiphiles self-assemble into nanofibers. ► They form viscoelastic hydrogels in aqueous suspension. ► We report on two new bolaamphiphiles with sulfur atoms in the spacer chain. ► Heteroatoms in the spacer chain alter the properties of nanofibers and hydrogels. ► Aggregation into fibers and gelation is critically dependent on steric effects.