We used ring-opening living polymerization to synthesize various linear poly(ethylene oxide−b−caprolactone) (PEO-b-PCL, EC) diblock copolymers featuring PCL blocks of various molecular weights and prepared phenolic resins with various double-decker silsesquioxane (DDSQ) cage compositions in the form of phenolic/DDSQ (PDDSQ) hybrids. Upon forming PDDSQ/EC blends, competitive hydrogen bonding of the phenolic OH units of PDDSQ occurred with both ether units of the PEO block and C�O units of the PCL block, with the fraction of hydrogen-bonded C�O groups increasing upon increasing the PDDSQ compositions but decreasing upon increasing the molecular weight of the PCL block in EC diblock copolymers. Small-angle X-ray scattering revealed the self-assembled structures and corresponding phase diagram of these PDDSQ/EC blends after thermal polymerization at 150 °C, with the d-spacing increasing upon increasing the molecular weight of PCL block in the EC diblock copolymers. After removal of the EC diblock copolymer template, we obtained mesoporous phenolic/DDSQ hybrids possessing high surface areas and pore volumes, with the highly ordered mesoporous structures featuring double-gyroid, hexagonal-packing cylindrical, spherical, and even Frank−Kasper (FK) structures depending on the molecular weight of PCL block and the content of the PPDSQ hybrid. Overall, this study provides a general principle for obtaining mesoporous double-gyroid and FK phases mediated by diblock copolymer compositions through competitive hydrogen-bonding interactions.

Anionic living polymerization was used to prepare a diblock copolymer of poly(styrene-b-4-vinyl pyridine) (PS-b-P4VP), and a phenolic resin with a double-decker silsesquioxane (DDSQ) cage structure was used to form a phenolic/ DDSQ hybrid (PDDSQ-30 with 30 wt.% DDSQ). Strong intermolecular hydrogen bonding could be confirmed through the hydroxyl (OH) groups of PDDSQ hybrid with the pyridine group of the P4VP block in PDDSQ-30/PS-b-P4VP blends based on Fourier transform infrared spectroscopy analyses, where increasing PDDSQ concentrations resulted in a higher proportion of hydrogen-bonded pyridine groups. After thermal polymerization at 180 °C, the self-assembled structures of these PDDSQ/PS-b-P4VP blends were revealed by data from small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), where the d-spacing increased with raising PDDSQ concentration. Because relatively higher thermal stability of the PDDSQ hybrid than pure phenolic resin and PS-b-P4VP template, we can obtain the long ranger order of mesoporous PDDSQ hybrids after removing the PS-b-P4VP template, which reveals the high surface area and high pore volume with cylindrical and spherical structures corresponding to the PDDSQ compositions that are rarely observed by using pure phenolic resin as the matrix and could be used in supercapacitor application.