Polypyrrole (PPy) is a conjugated polymer that shows excellent electrical conductivity, as well as antibacterial properties. The electrical conductivity is an intrinsic property of PPy because of its conjugated chemical structure. Moreover, the bioactivity is likely due to the presence of positive charges along the backbone chain able to open the membrane cell of bacteria [1,2].PPy can be deposited to textiles by a direct chemical deposition [2] to produce heating fabrics. However, the separation between polymer synthesis and fabric coating would lead to benefits in terms of productivity, evenness, cost, wastewater and chemicals usage. This process is useful in particular for antibacterial textiles that requires low amount of coating to be effective.In this work, chemical synthesis of PPy was carried out following two methods: 1) in presence of the fabrics in the polymerization bath in order to produce heating fabrics with high amount of PPy; 2) without a textile substrate in order to produce a PPy dispersion in water suitable for a following deposition on fabrics by ultrasound or spraying.Method 1. Fabrics were cut to 20 x 20 cm and plunged in a 0.18 M solution of ferric sulphate (liquor ratio 50:1), then the monomer was added under stirring to a concentration of 0.06 M. The samples were pulled out from the polymerization bath after 4 h, rinsed in cold water, gently squeezed, and dried overnight at room temperature. Then, the samples were stored in a conditioned laboratory at 20°C and 65% RH at least 24 h before tests.Method 2. PPy was synthetized in presence of poly(styrene sulphate) in order to produce stable water dispersions of PPy nanoparticles. PPy was deposited on fabrics by an ultrasound-assisted deposition process or a spraying coating plant [3].The heating fabrics (PPy amount 27 % wt.), produced with the Method 1, showed excellent electrical properties (voltage: 9 V, electrical current: 108 mA, electrical resistance: 83 ohm, average surface temperature increase: 3.4°C).Antibacterial tests were carried out according to ISO 20743 against Staphylococcus aureus and Escherichia coli on fabrics produced with the Method 2 at different PPy amount. The fabrics with the higher amount of PPy (3.7 % wt.) showed excellent antibacterial properties (~100% of efficacy) against both bacteria.
Heating And Antibacterial Textiles By Polypyrrole Coating
Alessio Varesano;Diego Omar Sanchez Ramirez;Cinzia Tonetti;Claudia Vineis
2019
Abstract
Polypyrrole (PPy) is a conjugated polymer that shows excellent electrical conductivity, as well as antibacterial properties. The electrical conductivity is an intrinsic property of PPy because of its conjugated chemical structure. Moreover, the bioactivity is likely due to the presence of positive charges along the backbone chain able to open the membrane cell of bacteria [1,2].PPy can be deposited to textiles by a direct chemical deposition [2] to produce heating fabrics. However, the separation between polymer synthesis and fabric coating would lead to benefits in terms of productivity, evenness, cost, wastewater and chemicals usage. This process is useful in particular for antibacterial textiles that requires low amount of coating to be effective.In this work, chemical synthesis of PPy was carried out following two methods: 1) in presence of the fabrics in the polymerization bath in order to produce heating fabrics with high amount of PPy; 2) without a textile substrate in order to produce a PPy dispersion in water suitable for a following deposition on fabrics by ultrasound or spraying.Method 1. Fabrics were cut to 20 x 20 cm and plunged in a 0.18 M solution of ferric sulphate (liquor ratio 50:1), then the monomer was added under stirring to a concentration of 0.06 M. The samples were pulled out from the polymerization bath after 4 h, rinsed in cold water, gently squeezed, and dried overnight at room temperature. Then, the samples were stored in a conditioned laboratory at 20°C and 65% RH at least 24 h before tests.Method 2. PPy was synthetized in presence of poly(styrene sulphate) in order to produce stable water dispersions of PPy nanoparticles. PPy was deposited on fabrics by an ultrasound-assisted deposition process or a spraying coating plant [3].The heating fabrics (PPy amount 27 % wt.), produced with the Method 1, showed excellent electrical properties (voltage: 9 V, electrical current: 108 mA, electrical resistance: 83 ohm, average surface temperature increase: 3.4°C).Antibacterial tests were carried out according to ISO 20743 against Staphylococcus aureus and Escherichia coli on fabrics produced with the Method 2 at different PPy amount. The fabrics with the higher amount of PPy (3.7 % wt.) showed excellent antibacterial properties (~100% of efficacy) against both bacteria.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
