pH‐responsive cotton fibre dyed by natural madder dye

Abstract

pH-responsive cotton can be used as a flexible sensor because it changes colour with pH. However, the safety of some synthetic pH-responsive dyes is uncertain, so the application of pH-responsive cotton to wounds is limited. Herein, natural madder dye was selected to explore the dyeing conditions and produce safe, pHresponsive cotton. Based on experimental data and computational calculations, the variation in the conjugation of the molecule was responsible for the colour change of the cotton dyed with madder. When the pH of the madder solution increases, the phenolic hydroxyl group of the alizarin, which is its main component, is ionised, and the colour changes from yellow to purple. The effect of the dye concentration was studied, and the results showed that the higher the dye concentration, the more obvious the colour change of the cotton. The reversibility of cotton dyed with madder was investigated, and the results showed that there was a good reversible transformation with changing pH. The reversibility time of the colour change was less than 20 seconds.How to cite this article: Zhu S, Huang Z, Yu X, et al. pH-responsive cotton fibre dyed by natural madder dye.

Overview on natural dyes and their IR-spectra – Part I: Plant based dyes with naphthoquinone and anthraquinone structure

“…The dyeing properties of natural madder dye on wool and cotton fibers as function of alkaline pH is intensively presented by Montazer et al and Zhu et al [49][50][51]. Good overviews on the influence of different mordants on the fastness properties, UV-protective and antimicrobial functionality are given by Zarkogianni et al and Ibrahim et al [45,52].…”

PENGARUH pH PADA PENCELUPAN BENANG AKRILAT DENGAN ZAT WARNA DISPERSI

“…Perubahan warna pada hasil pencelupan dengan zat warna dispersi juga dapat terjadi karena fenomena halokromisme, yaitu perubahan warna ketika berada dalam kondisi pH yang berbeda. [23][24][25] Perubahan warna serat akrilat yang dicelup dalam suasana alkali pada penelitian ini dapat disebabkan oleh fenomena halokromisme, yaitu struktur zat warna mengalami konjugasi pada pH yang berbeda dan terjadi proses protonasi atau deprotonasi, seperti digambarkan pada reaksi zat warna berstruktur azo yang berubah menjadi hidrazo (Gambar 5). Dalam suasana asam, zat warna dispersi dengan kromofor azo akan mengalami protonasi pada atom nitrogen (N + ) dan terjadi mekanisme konjugasi seperti dijelaskan oleh Griffiths dkk.…”

Alizarin old and new: Extraction techniques for coloration, advances in detection methods for historical textiles and novel applications as a functional dye

“…40 Alizarin has been well known as an abundant component of red dyes extracted from Rubiaceae family plants, which provide a variety of shades and colouring properties for dyed textiles depending on the dyeing conditions. [41][42][43] The current study provides a review of the natural alizarin compound with respect to its history, extraction, identification and applications. The review starts with a brief introduction to the scientific discovery and presence of alizarin in Rubiaceae family plants, followed by a summary of conventional and advanced extraction methods for obtaining alizarin from its botanical provenance.…”

“…Alizarin (C 14 H 8 O 4 or 1,2‐dihydroxyanthraquinone) is an organic colourant belonging to the anthraquinone family with a parental structure of 9,10‐anthracenedione and two adjacent hydroxyl (–OH) groups in the C‐1 and C‐2 positions 40 . Alizarin has been well known as an abundant component of red dyes extracted from Rubiaceae family plants, which provide a variety of shades and colouring properties for dyed textiles depending on the dyeing conditions 41–43 . The current study provides a review of the natural alizarin compound with respect to its history, extraction, identification and applications.…”