Resumo:
The use of the surgical mask as we know it today began in Germany in 1897 and its
effectiveness as a microbial barrier is recognized. However, there are some factors that can
compromise the protective effect of a surgical mask, and this effect is only maintained when
the surface layer of the mask is hydrophobic and dry. In this context, there is a need to replace
masks that are wet from prolonged use or that have been contaminated with blood or other
secretions with clean masks, which cannot always be done immediately during emergency
procedures. In addition, the hands of healthcare workers can be contaminated during the
removal of surgical masks. The coating of surfaces by different metals can give these coated
materials antimicrobial activity. In this context, titanium dioxide (TiO2) has known
antimicrobial activity and is used in a wide variety of biological applications. In addition,
coatings made up of silica particles, TiO2 or other oxides to modify the roughness of surfaces
in order to make them hydrophobic. The sol-gel method can be applied to obtain a hydrophobic
coating and this method involves the hydrolysis of a silica precursor source, such as tetraethyl
orthosilicate (SiO2), with alcohol at low temperatures. Therefore, the present dissertation aims
to develop a coverage with antimicrobial properties, based on the preparation of particles (Ps)
of TiO2 with SiO2, on the textile composition of 100% polypropylene (PP) used for making
surgical masks. The study was carried out through the following treatments: (a) immersion of
tissue in tetraethylorthosilicate (SIO2) solution, PP/SIO2 sample; (b) immersion of tissue in
SIO2 solution and after curing, sample PP/SiO2-curing; (c) immersing the tissue in SIO2 solution
and after curing the tissue is immersed in titanium isopropoxide solution, sample PP/SIO2-
curing-TiO2; (d) immersion of tissue in SiO2 solution, followed by immersion in titanium
isopropoxide solution and finally curing, sample PP/SiO2-TiO2-curing. The microcrystalline
structure and morphology of the samples were analyzed by X-ray diffraction (XRD) and
electron microscopy (SEM). The degree of hydrophobicity of the surface was evaluated by
measuring the contact angle. Antimicrobial activity was evaluated by the bacterial growth
inhibition technique. The data obtained by XRD confirmed the crystalline pattern of the PP
tissue in all analyzed samples. The amorphous SiO2 diffraction peak was only observed in the
PP/SiO2-Cure and PP/SiO2-TiO2-Cure samples. TiO2 diffraction peaks were only observed in
the PP/SiO2-TiO2-cure sample. The SEM showed in all analyzed samples the PP non-woven,
formed by 18.5 m wide interwoven microfibers. The SEM-EDS showed the low incorporation
of TiO2 in the PP non-woven. The contact angle showed the highest degree of hydrophobicity
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in the PP/SiO2-curing sample. There was no inhibition of bacterial growth in Kirby Bauer,
however, in the biofilm analysis, the PP + TiO2 + SiO2 + Cura sample showed a decrease in
bacterial biomass.