The chemical composition of rainwater can serve as an indicator for the excess of acidifying
air polluting substances. The pH value of rainwater in the presence of sulphur dioxide and
nitrogen oxides, the precursors of acid rain, falls below pH 5.6, which is the average value of
rainwater. In this thesis, we report on tailoring a halochromic textile for the design of a
functional raincoat which informs the wearer about the presence of pollutants in the air by an
immediate change of colour. For this purpose, the pH-sensitive Bromocresol Green dye, which
performs a colour change below 3.6 (yellow) and above 5.4 (blue), was used to dye a
polyamide 6 fabric. In addition, the dyed polyamide 6 fabric was treated with water and oil
repellent finish. Colour and colour change before and after immersion of untreated and
treated dyed samples in buffers solutions of different pH values were spectrophotometrically
evaluated using CIELAB colour space. Colour fastness to rubbing, washing, light, and the water
and oil repellency of dyed fabrics were determined according to valid SIST EN ISO standards.
It was found that the untreated, dyed polyamide 6 fabric undergoes reversible colour change
more quickly and more clearly than treated polyamide 6 fabric. The dyed polyamide 6 fabric
had good colour fastness to rubbing, domestic and commercial laundering, whilst colour
fastness to light is poor. Moreover, the dyed polyamide 6 fabric is pH responsive, despite
degradation of dye under xenon light, regardless of whether it was after treated or not.
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