Design of pH Responsive Textile as a Sensor Material for Acid Rain

Abstract

The chemical composition of rainwater can serve as an indicator of the excess of acidifying air pollutants. 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 limit value for acid rain. In this research, the tailoring of halochromic textile was examined for the design of a functional textile that can serve as a sensor and inform the wearer about the presence of pollutants in the air by means of an immediate colour change. For this purpose, a polyamide 6 fabric was dyed with the pH-sensitive Bromocresol green dye, which causes a colour change below pH 3.6 (yellow) and above pH 5.4 (blue). In addition, the dyed polyamide 6 fabric was treated with a water and oil repellent finish. Colour and colour change before and after immersion of unfinished and finished dyed samples in buffer solutions with different pH values were evaluated spectrophotometrically using the CIELAB colour space. The colour fastness to rubbing, washing, and light, and the water and oil repellency of the dyed fabrics were determined according to valid SIST EN ISO standards. The results showed that the unfinished dyed polyamide 6 fabric undergoes a reversible colour change faster and more clearly than the finished dyed polyamide 6 fabric. The dyed polyamide 6 fabric had good colour fastness to rubbing and domestic and commercial laundering, while the colour fastness to light was poor. In addition, the dyed polyamide 6 fabric was pH-sensitive, despite dye degradation under xenon light, regardless of whether it was finished.

COVID-19 recovery rate and its association with development

“…Large scale testing could be useful in identifying cases and could, thus, be useful in treatment and recovery. [ 32 ] There are studies that have classified districts into categories to assess the pandemic situation in them and suggest optimization of monitoring techniques (screening, closedown, curfews, lockdown, evacuations, legal actions, etc. ), which could be immensely helpful not only for the government, the medical fraternity, and other frontline workers such as the police and sanitation workers but also for those involved in policymaking and program implementation.…”

The colors of pre‐Hispanic textiles from cemeteries in the Quillagua and San Pedro de Atacama oases of Northern Chile

“…These spectra can then be converted into points in different three‐dimensional spaces 92 . One of the most commonly used systems for color description is the three‐dimensional CIELAB space, the acronym arising from CIE (Comission Internationale de l´Eclairage) and the axes denominated L *, a *, b *, where L * corresponds to lightness, a * to the red‐green component, and b * to the blue‐yellow component 93 The CIELAB system is commonly employed to describe and compare colors of dyes used in the textile industry 91,94‐100 and has the added advantage of being amenable to statistical analysis. Although the reflectance spectra may be acquired noninvasively using fiber optics reflectance spectroscopy 91 or, more recently, a scanning hyperspectral lidar, 101 the equipment at our disposal required the extraction of samples from the textiles.…”

Application of Smart and Functional Dyes in Textiles

“…Chemo chromic dyes can be used in identify the proteins (of certain microbes) with change of colour. This identification with changing colour indicates the presence of microbes in textiles [59]. Therefore, Application area of Chemo chromic dyes can be widened to medical textiles bandages [60].…”