# Cotton Terry Textiles with Photo- and Bio-Activity in a Model Study and Real Conditions
## 2 Materials and Methods
### Material Characterisation
#### 2.2.2 Textile Material Characterisation  
Morphological observation of ZnO and TiO\({}_{2}\) finished textiles was carried out using Scanning Electron Microscope (SEM) VEGA3-SBU (Tescan, Brno, Czech Republic). The elemental analysis of modified textiles was performed by energy dispersive X-ray spectroscopy (EDX) (Oxford Instruments Analytical, Abingdon, England). Before SEM-EDX investigation, the samples were placed on carbon plasters and coated with gold using Cressington Sputter Coater 108 auto (Cressington Scientific Instruments UK, Watford, England). In order to analyze the selected properties of the finished terry woven fabric towels, surface mass, time of water absorption and selected color fastness were determined. Figure 1: Schematic representation of finishing processes. The surface mass was measured in accordance with [36]. Samples of terry fabric with dimensions of 10 cm \(\times\) 10 cm were weighed and the results are the arithmetic mean of five weightings. The time of absorption was determined according to [37]. Samples of towels before and after modification with dimensions of 10 cm \(\times\) 10 cm were laid on the surface of the water and the duration of the complete immersion of the samples was recorded. The time of absorption is the arithmetic mean of five measurements. Fastness to washing in 60 \({}^{\circ}\)C was carried out according to [38] was determined in accordance with [39]. A grey scale was selected to evaluate color fastness to washing and rubbing. The ability of a cotton surface modified with photocatalytic compounds to decompose staining particles was tested. Self-cleaning properties were determined using 100% cotton woven fabric (made with bleached cotton yarn) of diagonal wave, desized and modified under laboratory conditions. A padding bath with the same composition as in industrial conditions was applied using a laboratory padding-squeezing machine ([PERSON], Zurich, Switzerland). The pressure of padding-squeezing rolls was 40 kG/cm. Then, the cotton samples were dried at 150 \({}^{\circ}\)C for 3 min using a laboratory starter drying-curing machine, ([PERSON], Zurich, Switzerland). Prior to the self-cleaning experiment, modified cotton samples were stored in the dark for 2 days. Blackcurrant nectar containing 25% blackcurrant juice (Hortex Sp. z o.o., Warszawa, Poland) was selected to assess self-cleaning properties. Juice staining was applied onto the fabric surface using stamp printing. Printed samples were dried in the dark. One-half of stained samples (control and modified) were irradiated for 6 h using a 160 W mercury lamp (Solar Glo PT2193, Exo Terra, Montreal, QC, Canada) with a spectrum similar to the spectrum of sunlight at a distance of about 30 cm above the sample surface. The UVA/B radiation was at an intensity of approximately 1.4 mW/cm\({}^{2}\). The UVA/B radiation intensity was monitored by means of a UV-AB ST513 SENTRY radiation meter (Sentry Optronics Corp., Taipei, Taiwan). The irradiated samples were sprayed with distilled water before and after each hour of irradiation. The other half of stained samples were stored in the dark. The stained samples (irradiated and unirradiated) were subjected to color measurements using the Spectraflash 300 colorimeter (DataColor, Rotkreuz, Switzerland). Prior to measurement, the instrument was calibrated according to the manufacturer's instructions. The light reflectance R(%) was measured in the range of 400-700 nm. The self-cleaning action was monitored by comparing the K/S values, the color differences and CIE L*a*b* color system between irradiated and unirradiated stained samples. L* is a coordinate of lightness, a* and b* are termed opponents to color axes.