Three-Dimensional Self-Assembly of Spherical Block Copolymer Domains into V-Shaped Grooves

Abstract

The self-assembly of a spherical-morphology block copolymer into V-shaped grooves has been investigated. Although spherical morphology block copolymers typically form a bcc sphere array in bulk, the V groove promotes the formation of a well-ordered fcc close-packed sphere array with the (111) planes of the array parallel to the groove walls. The sphere size in the block copolymer adjusts depending on the commensurability between the periodicity of the block copolymer and the film thickness within the V groove. The top surface of the close-packed array, parallel to the substrate, shows a square symmetry, unlike the hexagonal symmetry seen in monolayers of spherical domains, which may provide a useful geometry for block copolymer lithography.

Thin films of complexed block copolymers

“…21,22 In frustrated films, other packing morphologies such as face centered cubic (FCC) have also been found. 23 Furthermore, the spherical morphology does not contain any continuous block copolymer interfaces along which block copolymer chains …”

Synthesis and Solution Self‐Assembly of Polyisoprene‐block‐poly(ferrocenylmethylsilane): A Diblock Copolymer with an Atactic but Semicrystalline Core‐Forming Metalloblock

“…[270][271][272][273] PS-b-PFDMS thin films were assembled under confinement in etched nanochannels with differing widths (30 -80 nm) followed by O2 RIE. 273,274 When the row spacing of the diblock copolymer and the channel width were equal, spheres of PFDMS were formed. As the width of the nanochannels increased, hence becoming incommensurate to the period of the BCP, elliptical domains were obtained due to distortion of the PFDMS spheres, as shown in Figure 23.…”

Three‐dimensional Directed Assembly of Block Copolymers together with Two‐dimensional Square and Rectangular Nanolithography

“…[ 23 ] In multilayer fi lms confi ned in V-shaped grooves, spheres arrange in a face-centered cubic (FCC) structure with the (100) plane parallel to the fi lm surface. [ 26 ] Since sphere-forming block copolymers typically self-assemble into BCC structures in the bulk, [ 27 ] these fi lm morphologies represent deviations from bulk behaviour and are associated with the preferential wetting of one of the blocks of the copolymer at the substrate or free surface. By carefully controlling the boundary conditions and fi lm thickness, 1) the BCC morphology can be realized in thin fi lms, 2) the domain structures can be directed to assemble into desirable 3D architectures on chemical patterns, and 3) the (100) plane of the BCC unit cell can be induced to present itself on the surface of the block copolymer fi lm.…”