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Zinc oxide superstructures in colloidal polymer nanocomposite films: Enhanced antibacterial activity through slow drying

journal contribution
posted on 24.01.2020 by Yichen Dong, Maialen Argaiz, Boshen He, Radmila Tomovska, Tao Sun, Nacho Martin-Fabiani-Carrato
Achieving control over the distribution of biocides across the thickness of polymer nanocomposite films is one of the largest challenges to develop efficient antibacterial surfaces. In such applications, it is key to maximize the biocide presence at the film top surface to ensure contact with bacteria. Here, we make use of evaporation driven colloidal self-assembly to control the vertical distribution of biocides in polymer composite films cast from colloidal blends of polymer and zinc oxide (ZnO) nanoparticles. We present a thorough study which shows that the evaporation rate and ZnO volume fraction have a strong impact on the final film architecture and on its wetting and antibacterial properties. For high enough ZnO volume fraction, the ZnO nanoparticles assemble in superstructures on top of the film, which are higher the slower the evaporation rate used, and maximum ZnO surface coverage achieved through slow film drying. At high ZnO volume fraction (ϕ = 0.29), the zone of inhibition diameter against Escherichia coli increases as evaporation rate decreases, with the nanocomposite films having the strongest antibacterial activity when formed at slow evaporation rate. We propose a model for the formation of these colloidal superstructures based on the segregation of large (polymer) and small (ZnO) particles during drying, followed by the assembly of small particles around packed large particles due to differences in the surface charge of the two populations. Our work provides valuable guidelines for the design and assembly of not only antibacterial colloidal films but also a wider range of functional colloidal polymer films including abrasion resistant, self-cleaning, and others.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering
  • Materials

Published in

ACS Applied Polymer Materials

Volume

2

Issue

2

Pages

626 - 635

Publisher

American Chemical Society (ACS)

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 ACS Applied Polymer Materials copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acsapm.9b00991.

Acceptance date

08/01/2020

Publication date

2020-01-08

Copyright date

2020

ISSN

2637-6105

Language

en

Depositor

Dr Nacho Martin-Fabiani Carrato. Deposit date: 21 January 2020

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