Development of robust Cu2O and ZnO coated polypropylene fabrics by AP-SALD for antimicrobial applications
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Date
2022-01-04
Authors
Gurbandurdyyev, Guvanch
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Nowadays, the textile industry is revolutionizing by adding special functionalities and properties to
textiles. Especially with the emergence of COVID-19, textile functionalization has attracted the focus
of researchers for antimicrobial applications. Cuprous oxide (Cu2O) and zinc oxide (ZnO) are two
oxides, which are known to have antiviral and antibacterial properties, respectively.
Atmospheric-pressure spatial atomic layer deposition (AP-SALD) is a relatively new method, which
allows high-quality, high-throughput, conformal, pinhole-free, uniform coatings at the nanometer scale and eliminates the slow speed and vacuum requirements that hinder conventional atomic
layer deposition. In this thesis, spun-bond polypropylene (PP) fabrics that are used as an outer
layer of N95 respirators were coated with Cu2O and ZnO nanocoatings by AP-SALD. To the best of
my knowledge, this is the first time that fabrics have been coated by AP-SALD, which is a promising
method for mass production. An important property that textile coatings must have is good
adhesion, which was fulfilled by AP-SALD in this work. Unlike coatings on rigid substrates,
measuring the thickness of coatings on textiles is challenging due to the porosity and uneven
surface of fabrics. In-situ reflectometry was utilized to study the growth rate of coatings by applying
the Virtual Interface Method (VIM), which uses the reflectance intensity at a single wavelength over
time. The growth rate per cycle (GPC) of depositions was estimated by analyzing the resulting
damped oscillatory pattern.
The purpose of coating the spun-bond PP is to use it, especially Cu2O-coated PP, for antimicrobial
N95 respirators. For this reason, it is important to ensure that coatings do not affect the filtration
efficiency of fabrics. Penetration percentages (100 – filtration efficiency) of coated fabrics were
measured. Results indicate that the coatings do not have an obvious impact on the filtration
efficiency. Finally, since it is well-known that Cu2O shows an excellent antiviral performance against
many viruses, including SARS-CoV-2, the cytotoxicity of Cu2O coatings deposited by AP-SALD
against living cells was examined with Alamar blue (AB) and 5-carboxyfluorescein diacetate (CFDA)
assays to check their compatibility for human use. Based on the results, Cu2O – coated PP fabrics
coated at 100 °C seem to be safe for use in N95 respirators.
Description
Keywords
functional textiles, AP-SALD, thin films, conformal coatings, antiviral, polypropylene, copper oxide, zinc oxide, in-situ reflectometry