Phase Behavior of Neat Triblock Copolymers and Copolymer/Homopolymer Blends Near Network Phase Windows

Abstract

The phase behavior of poly(isoprene-b-styrene-b-methyl methacrylate) (ISM) copolymers near the styrene-rich network phase window was examined through the use of neat triblock copolymers and copolymer/homopolymer blends. Both end-block and middle-block blending protocols were employed using poly(isoprene) (PI), poly(methyl methacrylate) (PMMA), and poly(styrene) (PS) homopolymers. Blended specimens exhibited phase transformations to well-ordered nanostructures (at homopolymer loadings up to 26 vol % of the total blend volume). Morphological consistency between neat and blended specimens was established at various locations in the ISM phase space. Copolymer/homopolymer blending permitted the refinement of lamellar, hexagonally packed cylinder, and disordered melt phase boundaries as well as the identification of double gyroid (Q 230 ), alternating gyroid (Q 214 ), and orthorhombic (O 70 ) network regimes. Additionally, the experimental phase diagram exhibited similar trends to those found in a theoretical ABC triblock copolymer phase diagram with symmetric interactions and statistical segments lengths generated by Tyler et al.

Block copolymer electrolytes for rechargeable lithium batteries

“…There are five common morphologies for AB diblock copolymers including body‐centered cubic spheres or close‐packed spheres (S or S cp ), hexagonally‐packed cylinders (hex), double gyroid (G), orthorhombic network (O), and lamellae (lam). In addition to morphologies in the diblock copolymer system, an alternating gyroid (G A ) is shown in the triblock copolymer system . Several reports have shown that network morphologies, such as the gyroid, exhibit superior mechanical properties relative to their one‐ (1D) and two‐dimensional (2D) counterparts (e.g., hex and lam) due to the continuity of the mechanical supporting domain .…”

Regulation of crystalline morphologies and mechanical properties of olefin multiblock copolymers by blending polymer with similar architecture of constituent blocks

“…[17] An elegant approach to regulate the properties of block copolymers lies in blending with polymers possessing architecture similar to one of the constituent blocks. [15,[18][19][20][21][22] This allows targeting a multitude of bulk morphologies based on one single block copolymer by simply adjusting the overall blend composition, leading to optimized end-use properties. Actually, new materials with tailored features are also possible to be created through blending with elaborate design.…”

Design and Synthesis of Network-Forming Triblock Copolymers Using Tapered Block Interfaces

“…10 Based on polymer composition, our P(I-IS-S-SM-M) was expected to self-assemble into hexagonally-packed cylinder structures. However, our tapered triblock material was found to form an alternating gyroid (Q 214 ) network.…”