Perpendicular Structure Formation of Block Copolymer Thin Films during Thermal Solvent Vapor Annealing: Solvent and Thickness Effects

Abstract

Solvent vapor annealing of block copolymer (BCP) thin films can produce a range of interesting morphologies, especially when the perpendicular orientation of micro-domains with respect to the substrate plays a role. This, for instance, allows BCP thin films to serve as useful templates for nanolithography and hybrid materials preparation. However, precise control of the arising morphologies is essential, but in most cases difficult to achieve. In this work, we investigated the solvent and thickness effects on the morphology of poly(styrene-b-2 vinyl pyridine) (PS-b-P2VP) thin films with a film thickness range from 0.4 L0 up to 0.8 L0. Ordered perpendicular structures were achieved. One of the main merits of our work is that the phase behavior of the ultra-high molecular weight BCP thin films, which hold a 100-nm sized domain distance, can be easily monitored via current available techniques, such as scanning electron microscope (SEM), atomic force microscope (AFM), and transmission electron microscope (TEM). Systematic monitoring of the self-assembly behavior during solvent vapor annealing can thus provide an experimental guideline for the optimization of processing conditions of related BCP films systems.

Thin films of PS/PS‐b‐pnipam and ps/pnipam polymer blends with tunable wettability

“…The fact that the 75/25 PS/PS‐ b ‐PNIPAM film requires more annealing time to become completely smooth is explained by the increased ratio of PS, which has a higher T g , close to the annealing temperature. As expected, in all cases, thermal annealing offers the required energy for chain rearrangement and leads to more ordered structures in the block copolymer films …”

Progress Report on Phase Separation in Polymer Solutions

“…[31] Copyright 2014, American Chemical Society; V) Reproduced with permission. [35] Copyright 2017, MDPI; IX) Reproduced with permission. [33] Copyright 2006, Elsevier; VII) Reproduced with permission.…”

“…Figure 1a lists a number of phase separation microstructures [28][29][30][31][32][33][34][35][36][37][38][39] in different polymer solutions. Figure 1a lists a number of phase separation microstructures [28][29][30][31][32][33][34][35][36][37][38][39] in different polymer solutions.…”

Self-Assembly Investigations of Sulfonated Poly(methyl methacrylate-block-styrene) Diblock Copolymer Thin Films

“…For example, Zhao et al employed a selective solvent during the SVA treatment of poly(methyl methacrylateblock-styrene) (PMMA-b-PS) and found that the resulting morphology depended on the swelling ratio of the segments [8]. According to Yang & Loose, for the poly(styrene-b-2vinylpyridine) (PS-b-P2VP) system, the obtained morphologies resulted in a perpendicular orientation with respect to the substrate surface only to film thickness of 0.4-0.8L o [9]. Nehache et al studied the triblock copolymer system poly(styrene-b-styrenesulfonic acid sodium salt-b-styrene) (PS-b-PSSNa-b-PS) dissolved at different compositions of tetrahydrofuran (THF)-water, finding the formation of a porous morphology at low and medium concentrations [10].…”