Antibiotic resistance is one of the most critical health issues to human health in the world. The emergence has stimulated intensive research in many fields, including the development of antibacterial fabrics and novel broad-range biocides for textiles. Polypyrrole (PPy) is a conjugated polymer that showed excellent antibacterial properties on textiles [1]. Bioactivity of PPy is likely due to the presence of positive charges along the backbone chain able to open the membrane cell of bacteria [2]. PPy has been easily synthesized and deposited on fabrics by chemical oxidative polymerization from solutions of the monomer. However, at industrial level, the separation between polymer synthesis and fabric coating would lead to benefits in terms of productivity, evenness, cost, wastewater and chemicals usage. In this work, chemical synthesis of PPy was carried out in presence of poly(styrene sulphate) (PSS) in order to produce stable water dispersions of PPy nanoparticles. Viscosimetric analysis displayed a significant interaction between PPy and PSS with the presence of PSS solution between the PPy nanoparticles. However, this feature seems to be positive for the high shear rates locally generated during the ultrasonic coating process. PPy nanoparticles were deposited on polyester fabrics by an ultrasound-assisted deposition process. In this case, the ultrasound "throwing stones" technique produces microjets that push the nanoparticles in water towards the fibres surface enhancing particle collision, penetration and deposition. Since PPy is black, a colorimetric analysis was used to quantify the amount of PPy deposited on fabrics. Moreover, scanning electron microscopy, infrared spectroscopy and thermogravimetric analysis were used to assess the PPy content. Antibacterial tests were carried out according to ISO 20743 against Staphylococcus aureus and Escherichia coli. The fabrics with the higher amount of PPy (4 g/m2) showed excellent antibacterial properties against both bacteria. In particular, a bacterial reduction of 99.99999% (Log 7.00) was found against S. aureus and 99.999996% (Log 7.35) against E. coli.
Polypyrrole Nanoparticles Synthesis and Deposition by "Throwing Stones" for Antibacterial Textiles
A Varesano;DO Sanchez Ramirez;RA Carletto;C Tonetti;C Vineis
2018
Abstract
Antibiotic resistance is one of the most critical health issues to human health in the world. The emergence has stimulated intensive research in many fields, including the development of antibacterial fabrics and novel broad-range biocides for textiles. Polypyrrole (PPy) is a conjugated polymer that showed excellent antibacterial properties on textiles [1]. Bioactivity of PPy is likely due to the presence of positive charges along the backbone chain able to open the membrane cell of bacteria [2]. PPy has been easily synthesized and deposited on fabrics by chemical oxidative polymerization from solutions of the monomer. However, at industrial level, the separation between polymer synthesis and fabric coating would lead to benefits in terms of productivity, evenness, cost, wastewater and chemicals usage. In this work, chemical synthesis of PPy was carried out in presence of poly(styrene sulphate) (PSS) in order to produce stable water dispersions of PPy nanoparticles. Viscosimetric analysis displayed a significant interaction between PPy and PSS with the presence of PSS solution between the PPy nanoparticles. However, this feature seems to be positive for the high shear rates locally generated during the ultrasonic coating process. PPy nanoparticles were deposited on polyester fabrics by an ultrasound-assisted deposition process. In this case, the ultrasound "throwing stones" technique produces microjets that push the nanoparticles in water towards the fibres surface enhancing particle collision, penetration and deposition. Since PPy is black, a colorimetric analysis was used to quantify the amount of PPy deposited on fabrics. Moreover, scanning electron microscopy, infrared spectroscopy and thermogravimetric analysis were used to assess the PPy content. Antibacterial tests were carried out according to ISO 20743 against Staphylococcus aureus and Escherichia coli. The fabrics with the higher amount of PPy (4 g/m2) showed excellent antibacterial properties against both bacteria. In particular, a bacterial reduction of 99.99999% (Log 7.00) was found against S. aureus and 99.999996% (Log 7.35) against E. coli.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
