Textile integrable mechanochromic strain sensor based on the interplay of supramolecular interactions

•A simple supramolecular polymer/chromophore (polyvinylpyrrolidone/Disperse Red 1) coating on PDMS was demonstrated to show gradual stepless colour changing from orange to red upon elongation.•Dip-coating was employed to fabricate naked-eye observable mechanochromic strain sensor on commercial polyamide yarns.•Sensor yarns being able to stretch up to 75% elongation without breaking were fabricated.•Colour-changing can be quantitatively characterized by both UV–Visible spectroscopy and simple photography through RGB analysis.