Physical Chemistry

Water vapor induced self-assembly of islands/honeycomb structure by secondary phase separation in polystyrene solution with bimodal molecular weight distribution

Maciej Łojkowski Warsaw University of Technology, Materials Science and Engineering
,

Abstract

The formation of complex structures in thin films is of interest in many fields. Segregation of polymer chains of different molecular weights is a well-known process. However, here, polystyrene with bimodal molecular weight distribution, but no additional chemical modification was used. It was proven that at certain conditions, the phase separation occurred between two fractions of bimodal polystyrene/methyl ethyl ketone solution. The films were prepared by spin-coating, and the segregation between polystyrene phases was investigated by force spectroscopy. Next, water vapour induced secondary phase separation was investigated. The introduction of moist airflow induced the self-assembly of the lower molecular weight into islands and the heavier fraction into a honeycomb. As a result, an easy, fast, and effective method of obtaining island/honeycomb morphologies was demonstrated. The possible mechanisms of the formation of such structures were discussed.

Version notes

6 May 2021.

Content

Thumbnail image of Masło w masle_May21.pdf
download asset Masło w masle_May21.pdf 2 MB [opens in a new tab]

Supplementary material

Thumbnail image of TOC.tiff
download asset TOC.tiff 1 MB [opens in a new tab]
TOC
Thumbnail image of Supporting_information_may21.pdf
download asset Supporting_information_may21.pdf 1 MB [opens in a new tab]
Supporting information may21