Surface-relief gratings in halogen-bonded polymer-azobenzene complexes: A concentration-dependence study

Loading...
Thumbnail Image

Access rights

openAccess
publishedVersion

URL

Journal Title

Journal ISSN

Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2017-11-01

Major/Subject

Mcode

Degree programme

Language

en

Pages

Series

Molecules, Volume 22, issue 11, pp. 1-11

Abstract

In recent years, supramolecular complexes comprising a poly(4-vinylpyridine) backbone and azobenzene-based halogen bond donors have emerged as a promising class of materials for the inscription of light-induced surface-relief gratings (SRGs). The studies up to date have focused on building supramolecular hierarchies, i.e., optimizing the polymer-azobenzene noncovalent interaction for efficient surface patterning. They have been conducted using systems with relatively low azobenzene content, and little is known about the concentration dependence of SRG formation in halogen-bonded polymer-azobenzene complexes. Herein, we bridge this gap, and study the concentration dependence of SRG formation using two halogen-bond-donating azobenzene derivatives, one functionalized with a tetrafluoroiodophenyl and the other with an iodoethynylphenyl group. Both have been previously identified as efficient molecules in driving the SRG formation. We cover a broad concentration range, starting from 10 mol % azobenzene content and going all the way up to equimolar degree of complexation. The complexes are studied as spin-coated thin films, and analyzed by optical microscopy, atomic force microscopy, and optical diffraction arising during the SRG formation. We obtained diffraction efficiencies as high as 35%, and modulation depths close to 400 nm, which are significantly higher than the values previously reported for halogen-bonded polymer-azobenzene complexes.

Description

Keywords

Azobenzene, Halogen bonding, Photoresponsive, Supramolecular, Surface-relief grating

Other note

Citation

Stumpel, J E, Saccone, M, DIchiarante, V, Lehtonen, O, Virkki, M, Metrangolo, P & Priimagi, A 2017, ' Surface-relief gratings in halogen-bonded polymer-azobenzene complexes : A concentration-dependence study ', Molecules, vol. 22, no. 11, 1844, pp. 1-11 . https://doi.org/10.3390/molecules22111844