Phase behavior of polyisoprene-poly(butylene oxide) and poly(ethylene-alt-propylene)-poly(butylene oxide) block copolymers

Stable Thermotropic 3D and 2D Double Gyroid Nanostructures with Sub‐2‐nm Feature Size from Scalable Sugar–Polyolefin Conjugates

“…More specifically, at the lowest temperature, a pure L phase is initially observed up to a temperature of 83 8C, whereupon a new phase begins to grow in and becomes the only phase that is present at 117 8C (see lowest panel of Figure 2 2 b), the identity of this new phase was established as being the hexagonal perforated lamellar (HPL) phase of R " 3m symmetry in which the minor domains that punctuate major domain lamellae are positioned relative to each other in an ABCA stacked arrangement. [14] This structural assignment also provided the HPL unit cell parameters of a = 7.5 nm and c = 16.4 nm for Angewandte Chemie Communications a c/a ratio of 2.19, which is very similar to c/a values reported for other ABCA-stacked HPL phases of microphase-separated block copolymers. [14,15] Further heating of the HPL phase of 1 a above 117 8C resulted in the appearance of yet another phase, which becomes the only morphology that is present at 149 8C (see middle panel of Figure 2 a).…”

“…[14] This structural assignment also provided the HPL unit cell parameters of a = 7.5 nm and c = 16.4 nm for Angewandte Chemie Communications a c/a ratio of 2.19, which is very similar to c/a values reported for other ABCA-stacked HPL phases of microphase-separated block copolymers. [14,15] Further heating of the HPL phase of 1 a above 117 8C resulted in the appearance of yet another phase, which becomes the only morphology that is present at 149 8C (see middle panel of Figure 2 a). Figure 2 (q* = 0.1175 À1 ) to a DG Ia " 3d À Á phase with a unit cell length, a DG , of 13.1 nm.…”

“…For block copolymers, theoretical studies have concluded that the HPL morphology is a metastable state, and experimentally, it has been observed as a long-lived intermediate involved in order-order transitions between two equilibrium mesophases. [14,15,17] On the other hand, the DG phase is now widely accepted as being a thermodynamic equilibrium morphology, but with only a small window of stability within the phase diagram of microphase-segregated block copolymers of varying segregation strength. [5,17] In the present work, it is reasonable to assume that the same epitaxial relationships that have been previously proposed and documented for thermotropic L $ HPL, HPL $ DG, and DG $ C transitions in block copolymers assignments for pure phases obtained at temperatures shown in (a).…”

Observation of Double Gyroid and Hexagonally Perforated Lamellar Phases in ABCBA Pentablock Terpolymers

“…16,73 Only three observations of the regular HPL phase in unsheared diblock copolymers were reported, to the best of our knowledge, in the literature. 69,75,76 Highly regular HPL structures were observed in unsheared poly(styrene-b-ethylene-alt-propylene), 69 poly-(ethylene-alt-propylene-b-butylene oxide), 75 and poly(methyl methacrylate-b-vinyl-m-triphenylamine) diblock copolymers, 76 respectively. The 2D SAXS pattern shown in Figure 5c suggested that it was also possible to form an ordered HPL structure in linear ABCBA pentablock terpolymers by thermal annealing without any shearing.…”

Novel triblock copolymers comprising a polyrotaxane middle block flanked by PNIPAAm blocks showing both thermo- and solvent-response

“…Block copolymers have drawn tremendous attention in past decades due to their intrinsic properties such as self-assembly into unique core-shell micelles and/or vesicles in selective solvents, 1,2 and self-aggregate into Langmuir layers, 3 microsegregations, 4 columnar and island morphologies in bulk. 5 They show great promise to be used in the fields of stimuli-responsive materials, 2 controlled drug delivery, 6 force enhancement, 7 fabrication of superhydrophobic surface, 8,9 and so forth.…”