Template-assisted interfacial self-assembly of amphiphilic poly(ethylene oxide)–poly(propylene oxide)-based triblock copolymers for automatic control of molecular alignment

Abstract

Hierarchical self-assembled nanoarchitectures based on peculiar self-assembly of block copolymers are advantageous for the nanofabrication of functionally versatile materials with a wide range of potential applications from bioelectronic devices to flexible displays. Herein, we developed a simple yet efficient, cost-effective, scalable strategy for the fabrication of an ultrafast responsive and highly reliable self-constructed polymer nanolayer for automatic control of molecular alignment by using the template-assisted interfacial self-assembly of amphiphilic poly(ethylene oxide)–poly(propylene oxide)-based triblock copolymers. A new type of ultrathin polymer nanolayer was facilely fabricated on polar electrode surface using simple doping in liquid crystal (LC) medium and in situ interfacial self-assembly of a small amount of amphiphilic triblock copolymers in the closed LC cell. A hydrophobic and ultrathin polymer nanolayer with dense nanoneedle arrays formed by interfacial hydrogen bonding between hydrophilic poly(ethylene oxide) block and hydrophilic indium tin oxide electrode induces a spontaneous homeotropic alignment of LCs during programmed self-assembly process. Moreover, this facile approach endows the polymer nanolayer with ultrafast electro-optical switching and high molecular alignment force characteristics, as well as an excellent alignment stability during long-term operation. Compared to commercial polyimide layer, our polymer nanolayer accomplishes the ultrafast falling response time with an improvement of 55.3% and fast rising response time with a reduction of 36.4%.