New Insights in the Ion Beam Sputtering Deposition of ZnO-Fluoropolymer Nanocomposites

Maria Sportelli,Antonella Milella,Angelo Nacci,Marco Valentini,Rosaria Picca,Nicola Cioffi,Antonio Valentini

doi:10.3390/app8010077

Maria Sportelli, Antonella Milella + Show 5 more

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https://doi.org/10.3390/app8010077

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Abstract

Surface modification treatments able to confer antistain/antibacterial properties to natural or synthetic materials are receiving increasing attention among scientists. Ion beam co-sputtering (IBS) of zinc oxide (ZnO) and poly-tetrafluoroethylene (PTFE) targets allows for the preparation of novel multifunctional coatings composed of antimicrobial ZnO nanoparticles (NPs) finely dispersed in an antistain PTFE polymeric matrix. Remarkably, IBS has been proved to be successful in the controlled deposition of thin nanocoatings as an alternative to wet methods. Moreover, tuning IBS deposition parameters allows for the control of ZnONP loadings, thus modulating the antibacterial/antistain coating’s final properties. All the deposited coatings were fully characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and transmission electron microscopy (TEM) in order to obtain information on the materials’ surface composition, with deep insight into the nanocoatings’ morphology as a function of the ZnONP loadings. An analysis of high-resolution XP spectra evidenced a high degree of polymer defluorination along with the formation of inorganic fluorides at increasing ZnO volume ratios. Hence, post-deposition treatments for fluorides removal, performed directly in the deposition chamber, were successfully developed and optimized. In this way, a complete stoichiometry for inorganic nanophases was obtained, allowing for the conversion of fluorides into ZnO.

Highlights

Organic-inorganic composite materials are of primary interest for basic and technological applications, as inorganic nanophases’ inclusion in polymeric matrices is an efficient method to produce materials with unique chemical and physical properties, gathering together the characteristics of polymers and nanostructures [1]
We report on new insights into the Ion beam co-sputtering (IBS) co-sputtering of a Teflon-like thin film containing well-dispersed inorganic nanophases, starting from zinc oxide (ZnO) and PTFE ultrapure bulk targets, as we have already described before [45]
The ZnO cluster size increased with φ, and nanoparticle aggregation was observed at high φ values

Summary

Introduction

Organic-inorganic composite materials are of primary interest for basic and technological applications, as inorganic nanophases’ inclusion in polymeric matrices is an efficient method to produce materials with unique chemical and physical properties, gathering together the characteristics of polymers and nanostructures [1]. PTFE-based composite materials, containing inorganic nanophases, are well-known tools for the development of protective coatings [4], flexible electronic devices [5], super-hydrophobic self-cleaning surfaces [6,7,8,9,10], high thermal and electric conductive devices [11,12], sensors [13], and antimicrobials [14,15,16,17,18] Many such composites are nowadays prepared using deposition techniques, such as r.f. magnetron sputtering [19], ion beam sputtering [20], and plasma and.

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