Two tetrablock terpolymers of the S1IS2P type, where S, I, and P denote polystyrene, polyisoprene, and poly­(2-vinylpyridine), respectively, were prepared anionically. S1IS2P-1 (S1/I/S2/P = 0.35/0.16/0.34/0.15, four numbers being volume fractions of S1, I, S2, and P block chains) has a structure with double hexagonal cylinders, while S1IS2P-2 (S1/I/S2/P = 0.47/0.15/0.22/0.16) has an unusual double tetragonal structure. Moreover, 13 binary blends were prepared from these two parent polymers. Among them, five blends with α­(= φS1/φS2) covering the range 1.50 ≤ α ≤ 1.86 were confirmed to have a 3.3.4.3.4 Archimedean tiling structure, in which their P domains adopt five satellite I domains, while four blends with α covering the range 1.37 ≤ α ≤ 1.48 were revealed to be a quasicrystalline tiling structure with dodecagonal symmetry.

Hexagonally packed coaxial triply helical domains with a mesoscopic length scale in matrices were created from an S1IS2P tetrablock terpolymer/Sh homopolymer blend system, wherein S1, S2, and Sh denote polystyrene, I is polyisoprene, and P represents poly­(2-vinylpyridine). Two terpolymers, i.e., S1IS2P-3 (S1/I/S2/P = 0.50/0.17/0.19/0.14, M = 134k) and S1IS2P-4 (S1/I/S2/P = 0.58/0.16/0.10/0.16, M = 173k), were blended with Sh (M = 3k) at various concentrations. In the S1IS2P-3/Sh = 80/20 blend, the helical domain of P (o.d.= 19 nm; h.p. = 34 nm) was displayed by TEM, and the helical I phase (o.d. = 55 nm; i.d. = 29 nm; h.p. = 34 nm) was clearly demonstrated by 3D-TEM tomography. Essentially the same structure was confirmed to be created from the S1IS2P-4/Sh blend. These findings point out that S2 chains fill the gap between the I and P helices, and hence the intermediate S phase also has a helical nature. Moreover, it is worth noting that grains composed of hexagonally packed helices reveal homochirality.