Analysis of the Interdependence of Surface-Induced Pilling and Electrical Resistance of Cotton Knitwear

The occurrence of pilling affects the appearance and aesthetic properties of knitwear and leads to a shortened lifespan of underwear, which is usually worn directly on the skin and under the outer layers of clothing and is exposed to direct contact with various textile materials in a dynamic microclimate. The interdependence of surface-induced pilling and electrical resistance (i.e., conductivity), which also affects wearing comfort, has not been sufficiently investigated. This paper therefore analyzes how surface-induced pilling of different intensities affects the surface resistivity and vertical resistance, physical properties and moisture content of double jersey cotton knitwear under different relative humidity conditions (25%, 40%, 65% and 80%) using Pearson’s correlation coefficient and coefficient of determination. Pilling was induced using the modified Martindale method and two types of abrasives, with higher intensity and larger pills obtained with a rougher wool reference abrasive. It was found that the surface resistivity and vertical resistance of cotton knitwear increased after prolonged wear due to surface-induced pilling and that mass, thickness and moisture content were not directly related to changes in electrical resistivity. The results of the Pearson correlation analysis showed a strong and quantifiable correlation between the intensity of surface pilling and surface resistivity at relative humidity up to 65%, despite their high moisture absorption. This statistically confirms that the occurrence of pilling reduces the electrical conductivity of cotton knitwear, resulting in a lower wearing comfort of cotton-based underwear. This finding can be useful in the development of underwear with high durability and comfort.