Optimization of Diblock Copolymer Thin Film Self Assembly

Abstract

How can optimum long‐range order be achieved by self‐assembly of polystyrene/polymethylmethacrylate (PS/PMMA) block copolymers? Here the film thickness, annealing temperature, annealing time, and molecular weight are varied to derive optimum values for these parameters. The Figure shows SEM images of the microstructures obtained from M = 67 000 and M = 134 000 copolymers after solvolytic PMMA removal.

Effect of boron oxide/carbon arrangement of precursor derived from condensed polymer-boric acid product on low-temperature synthesis of boron carbide powder

“…Such a structural development in terms of both particle size and uniformity has been observed for a diblock copolymer subjected to thermal annealing well above the glass transition temperature. 12) This indicates that the low-temperature heat treatment process in the molten state without thermal decomposition leads to the densely packed B 2 O 3 /carbon arrangement in the precursor powder through the effect of thermal annealing on the polymer matrix. The nanoscale homogeneously arranged morphology of Precursor-2 is similar to that of nanoporous materials prepared from block copolymer precursors, 12),13) which are ideal self-assembled organic materials, meaning that the precise structural formation of the precursor can be achieved by the low-temperature heat treatment.…”

Block Copolymer Nanostructures for Technology

“…However, to generate a truly periodic pattern over a large area using density multiplication, the guiding pattern needs to have the same orientation as the BCP domains (i.e., posts to guide out-ofplane cylinders, trenches to guide lamellae or in-plane cylinders). This requires the thickness of the BCP layer to be appropriate for the desired patterns, and precise thickness control is critical [37]. Nevertheless, high density multiplying factor can be achieved, as exemplified by Tada et al, where the density can be increased up to nine times [16] using pre-patterned and etched surfaces.…”

Microdomain Orientation of PS-b-PMMA by Controlled Interfacial Interactions

“…[11][12][13][14][15] It has been also reported that the structure of self-assembled monolayers (SAMs) of alkylsiloxanes on SiOx/Si substrate plays an important role in determining the wetting behavior of block copolymer thin films, which can be correlated to the interfacial and surface energies. 16,17 For some commercial applications, the directed self-assembly of block copolymers leading to an perpendicular microdomain orientation in thin films is desired 13,[18][19][20][21] since this enables the use of the microdomain patterns as templates and scaffolds for nanolithographic applications. 22,23 This strategy has been achieved by surface modification, 24,25 strong electric field, 26,27 and solvent annealing.…”