Asymmetric Three-Component Bolaform Giant Surfactants Exhibit Rich Unconventional Phases

Self-assembly of block molecules into unconventional morphologies with ultrasmall feature sizes remains challenging. Here, we report the phase behavior of asymmetric bolaform giant surfactants, Si₄-PS_<i>n</i>-F, comprising a central polystyrene (PS) chain flanked by an oligodimethylsiloxane-functionalized polyhedral oligomeric silsesquioxane (SiPOSS) at one end and a perfluoroalkyl-functionalized POSS (FPOSS) at the other. Increasing the PS fraction reveals a rich sequence of ordered phases: three-phase lamellae, alternating elliptic cylinders (<i>c</i>2<i>mm</i>), alternating gyroids (<i>I</i>4₁32), and tetragonal cylinders (<i>p</i>4<i>mm</i>). Primary phase separation between strongly segregated FPOSS and PS/SiPOSS generates nanoconfinement, which drives the secondary segregation of weakly incompatible SiPOSS and PS to synergistically afford the final ordered structure. Furthermore, the shape anisotropy and rigidity of the terminal nanoparticles are critical for breaking the symmetry and stabilizing these unconventional phases. This work establishes bolaform giant surfactants as a robust platform for engineering tailored nanopatterns for next-generation semiconductor and data-storage applications.