Fundamental Principles and Emerging Opportunities for Selectively-Solvated Block Copolymer Networks in Nonpolar Media: A Perspective

Abstract

Block polymers remain an extensively studied class of macromolecules due to their ability to self-organize spontaneously as a result of microphase separation into a variety of ordered nanostructures, depending on the number of contiguous sequences (“blocks”) present and their sequential arrangement. These polymers are classified as multifunctional since they exhibit two or more different property sets during application. In this work, the focus is on bicomponent block copolymers composed of soft and hard segments arranged as linear triblock or higher-order multiblock copolymers and possessing the properties of a thermoplastic elastomer (TPE). Of particular interest are selectively-solvated TPEs, designated as TPE gels (TPEGs), with precisely- and composition-tunable properties. An important aspect of TPEs and their TPEG analogs is their elasticity, which reflects the ability of the soft block(s) to form a contiguous molecular network connected by dispersed microdomains composed of the hard block. Here, the origins of microphase separation and network formation in styrenic TPEs and TPEGs are explored, and experimental, theoretical, and simulation results are examined to elucidate chemistry-structure-property-processing (CSPP) relationships in these self-networking materials. Once such relationships are established, several unconventional technologies that can directly benefit from TPEGs, along with TPEGs fabricated from TPEs possessing different chemical moieties, are likewise considered.