Halochromic Materials (Year 2022)
A halochromic material or pH indicator is a material which changes colour when pH changes occur.
Neutral dyes
Halochromic dyes
pH is a rating of how acidic or alkaline a solution is on a scale from 0–14. A pH of 7 is considered neutral. Any pH value below 7 is considered acidic, and any pH value over 7 is considered alkaline.
Samples
Wool yarns
Cotton yarns