Frank–Kasperσphase in polybutadiene-poly(ε-caprolactone) diblock copolymer/polybutadiene blends

Abstract

Microphase-separated structures in a polybutadiene-poly(ε-caprolactone) diblock copolymer (PB-PCL)/polybutadiene homopolymer (PB) blend were investigated by small-angle x-ray scattering (SAXS). Non-equilibrium spherical micelles were observed at temperatures ranging between 60 and 100 °C. An SAXS profile with >60 scattering peaks was recorded at 140 °C. All the peak positions were in good agreement with theoretical Frank-Kasper σ phase peak positions. Thus, these results indicate the formation of a Frank-Kasper σ phase in the PB-PCL/PB blend at 140 °C.

Close-packed structures of the spherical microdomains in block copolymer–homopolymer binary mixture

“…PB-PCL and PB were synthesized by living anionic polymerization under high vacuum [10]. The number-average molecular weight (Mn) and…”

“…The molecular characteristics of PB-PCL and PB are given in Table 1. The blend samples were prepared according to the standard method [10]. The cast sample was dried under vacuum for 48 h at room temperature.…”

“…Our research group has investigated the phase behavior and structure of block copolymer/homopolymer binary mixtures. We recently reported that FCC, HCP, and Frank-Kasper σ phases are observed in block copolymer/homopolymer blends [9,10]. In this study, we investigated the dependence of the close-packed lattice on the amount of added homopolymer for polybutadiene (PB)-poly(ε-caprolactone) (PCL) diblock copolymer/PB blends.…”

Rapid One‐Step Synthesis of Complex‐Architecture Block Polymers Using Inductively “Armed–Disarmed” Monomer Pairs

“…Due to their diverse role as functional materials, coupled with potentially new applications, demand is on the rise . More recently, developments in block copolymers that form non‐traditional assemblies has garnered significant interest following the discovery of neoteric complex “quasicrystal‐like” structures . These nontraditional phases are stabilized by the presence of large spherical domains, which can be achieved via conformational asymmetry, chain architecture, or non‐uniform chain length .…”

“…[1] More recently, developments in block copolymers that form non-traditional assemblies has garnered significant interest following the discovery of neoteric complex "quasicrystal-like" structures. [3][4][5][6][7][8] These nontraditional phases are stabilized by the presence of large spherical domains, which can be achieved via conformational asymmetry, chain architecture, or non-uniform chain length. [9][10][11][12][13] Such massive periodic patterns, with unique phases, have potential applications as photonic crystals if larger selectively reacts with the more electrophilic MMA (consistent with literature [30,31] ) while the free radical, albeit less selective, primarily polymerizes styrene especially with rapid stoichiometric changes and diffusion limitation (due to depletion of MMA).…”