Mechanisms of alignment of lamellar-forming block copolymer under shear flow.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39718019.
- Also identified by DOI 10.1039/d4sm01241k and PMC identifier 11667677.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The potential applications of block copolymer thin films, utilising their self-assembly capabilities, are enhanced when achieving long-range ordering. In this study we explain the experimental alignment of lamellae under shear flow findings [S. Pujari <i>et al. Soft Matter</i>, 2012, <b>8</b>, 5258] and classify the alignment mechanisms based on shear rate and segregation, uncovering similarities to the systems subjected to electric fields, suggesting a common pathway of lamellae orientations. However, the presence of thin films surfaces introduces distinct features in the lamellae orientation under shear compared to electric fields. Notably, we observe the emergence of a three-dimensional rotation alongside the conventional two-dimensional rotation. Furthermore, a transient regime has been identified within the melting mechanism, which confirms the existence of the checkboard pattern proposed by Schneider <i>et al.</i> [<i>Macromolecules</i>, 2018, <b>51</b>, 4642]. These findings significantly enhance our understanding of block copolymer alignments and shed light on the intricate interplay between external fields and the lamellar structure.