Issue 27, 2021

Hybrid silica micro-particles with light-responsive surface properties and Janus-like character

Abstract

The present work highlights the synthesis and post-modification of silica-based micro-particles containing photo-responsive polymer brushes with photolabile o-nitrobenzyl ester (o-NBE) chromophores. For the synthesis of the polymer brushes, two different procedures were pursued. In the first approach, an amino-functional organosilane was covalently attached onto the silica surface followed by the thermal coupling of a mono-functional epoxy monomer containing o-NBE groups. In the second approach, a long wavelength absorbing Norrish Type I photoinitiator bearing functional trialkoxy silane moieties was immobilized across the silanol groups of the silica surface by condensation reaction. Upon visible light exposure, the photoinitator was homolytically cleaved and the formed radicals acted as anchor points for a grafting-from reaction. In particular, an acrylate monomer with o-NBE groups was grafted onto the surface of the micro-particles without inducing a premature cleavage of the o-NBE links. The photo-induced grafting reaction enabled the formation of photo-responsive polymer brushes within short reaction time and under mild reaction conditions. Once the polymer brushes were formed, the o-NBE groups were selectively cleaved upon UV light exposure. Additionally, particles with Janus-like properties were synthetized by first masking the grafted silica particles through a wax-water Pickering emulsion, followed by a selective UV irradiation of the unmasked particles’ domain. The formed carboxylic acid moieties were then used for the covalent attachment of a fluorescent biomolecule (Alexa Fluor546 conjugated Protein A). Zeta potential experiments and XPS spectroscopy confirmed the changes in the chemical surface composition of the silica particles prior to and after the surface modification and photocleavage processes. In addition, confocal microscopy images proved the selective anchoring of a fluorescent protein onto the surface of UV irradiated particles surface areas, giving rise to the versatility of o-NBE chemistry for the fabrication of light-responsive hybrid particles.

Graphical abstract: Hybrid silica micro-particles with light-responsive surface properties and Janus-like character

Supplementary files

Article information

Article type
Paper
Submitted
02 Dzi 2021
Accepted
12 Mud 2021
First published
12 Mud 2021

Polym. Chem., 2021,12, 3925-3938

Hybrid silica micro-particles with light-responsive surface properties and Janus-like character

A. Romano, M. Sangermano, E. Rossegger, I. Mühlbacher, T. Griesser, M. Giebler, G. Palmara, F. Frascella, I. Roppolo and S. Schlögl, Polym. Chem., 2021, 12, 3925 DOI: 10.1039/D1PY00459J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements