Perforated Layer Structures in Liquid Crystalline Rod−Coil Block Copolymers

Abstract

We report a novel observation of the tetragonal perforated layer structures in a series of rod-coil liquid crystalline block copolymers (BCPs), poly(styrene-block-(2,5-bis[4-methoxyphenyl]oxycarbonyl)styrene) (PS-b-PMPCS). PMPCS forms rigid rods while PS forms the coil block. Differential scanning calorimetry (DSC), polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), and transmission electron microscopy (TEM) techniques were used to investigate these rod-coil molecules, and a perforated layer structure was observed at f(PMPCS) approximately 0.37 in relatively low molecular weight (M(w)) samples and approximately 0.5 in high M(w) PS-b-PMPCS. This substantial phase boundary shift was attributed to the rod-coil nature of the BCP. The perforation obeys a tetragonal instead of hexagonal symmetry. The "onset" of perforation was also observed in real space in sample PS(272)-b-PMPCS(93) (f(PMPCS) approximately 0.52), in which few PS chains punctuate PMPCS layers. A slight increase in f(PS), by blending with PS homopolymer, led to a dramatic change in the BCP morphology, and uniform tetragonal perforations were observed at f(PMPCS) approximately 0.48.

Jacketed polymers: Controlled synthesis of mesogen‐jacketed polymers and block copolymers

“…The well-studied PS-b-PMPCS diblock copolymer showed unique self-assembly behaviors in dilute solutions and in bulk. [50][51][52][53] Especially, when the volume fraction of PMPCS changed slightly, the phase changed obviously. The exactly controlled length of PMPCS rod was achieved by TEMPO-mediated radical polymerization.…”

Facile Synthesis of Nanostructured Carbon through Self‐Assembly between Block Copolymers and Carbohydrates

“…Both SEM and TEM results confirm that the nanoporous carbon films exhibit 3-dimensional perforated lamellar pore structure. [29] To better understand the self-assembly process and formation of ordered 3-dimensional porous carbon nanostructure, we carried out GISAXS studies. We first studied the self-assembly behaviour of PS-P4VP before and after addition of carbohydrates.…”

Influence of liquid crystalline formation on the phase behavior of side-chain liquid crystalline block copolymers

“…It's obvious that the lamellar morphology dominates during the majority LC block weight fraction range (f w,PCBOA ¼ 46%e77%). Zhou et al found that in rodecoil BCPs, the lamellar phase was observed with the supramolecular PMPCS rods aligning parallel to the lamellar normal [15]. Shen et al reported that, for rodecoil BCPs, because long rods prefer a flat intermaterial dividing surface (IMDS), lamellar phases are stable in a wide range of composition even in some rodecoil BCPs with high compositional asymmetry [17].…”