Al nuumani et al. Highly porous magnetic Janus microparticles with asymmetric surface topology.pdf (1.74 MB)
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Highly porous magnetic Janus microparticles with asymmetric surface topology

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journal contribution
posted on 05.10.2020, 14:47 authored by Ruqaiya Alnuumani, SK Smoukov, Guido BolognesiGuido Bolognesi, Goran VladisavljevicGoran Vladisavljevic
Monodispersed magnetic Janus particles composed of a porous polystyrene portion and a nonporous poly(vinyl acetate) portion with embedded oleic acid-coated magnetic nanoparticles were generated using microfluidic emulsification followed by two distinct phase separation events triggered by solvent evaporation. The template droplets were composed of 2 wt% polystyrene, 2 wt% poly(vinyl acetate) and 0.5-2 wt% n-heptane-based magnetic fluid dissolved in dichloromethane (DCM). The porosity of polystyrene compartments was the result of phase separation between a non-volatile non-solvent (n-heptane) and a volatile solvent (DCM) within polystyrene-rich phase. The focused ion beam cross-sectioning and SEM imaging revealed high surface porosity of polystyrene compartments with negligible porosity of poly(vinyl acetate) parts, which can be exploited to increase the wettability contrast between the two polymers and enhance bubble generation in bubble-driven micromotors. The porosity of the polystyrene portion was controlled by varying the fraction of n-heptane in the dispersed phase. The particle composition was confirmed by scanning electron microscopy-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The fabricated particles were successfully magnetised when subjected to an external magnetic field, which led to their aggregation into regular 2D assemblies. The particle clusters composed of 2-4 individual particles could be rotated with a rotating magnetic field. Microfluidic generation of highly porous Janus particles with compositional, topological, and magnetic asymmetry provides a cost-effective, easy-to-implement yet highly robust and versatile strategy for the manufacturing of multifunctional smart particles.

Funding

Microfluidic methods for production of core/shell capsules using natural and synthetic biodegradable polymers EP/HO29923/1

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

Langmuir: the ACS journal of surfaces and colloids

Volume

36

Issue

42

Pages

12702–12711

Publisher

American Chemical Society

Version

AM (Accepted Manuscript)

Rights holder

© American Chemical Society

Publisher statement

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir: the ACS journal of surfaces and colloids, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.langmuir.0c02315

Acceptance date

03/10/2020

Publication date

2020-10-14

Copyright date

2020

ISSN

0743-7463

eISSN

1520-5827

Language

en

Depositor

Dr Goran Vladisavljevic. Deposit date: 3 October 2020