Time–temperature chromatic sensor based on polydiacetylene (PDA) vesicle and amphiphilic copolymer

Polydiacetylene (PDA) is an excellent color-changing indicator. In this paper, we demonstrate a new and interesting kind of time–temperature chromatic sensor based on PDA vesicle and amphiphilic polymer. In presence of amphiphilic polymers, PDA vesicles could gradually transit from blue to red, which was irreversible and regularly depended on the temperature, time, and properties of amphiphilic polymer (including the concentration, molecular weight, molecular structure, hydrophobicity, and thermo-sensitive property). Higher concentration of amphiphilic polymers resulted in lower color-transition temperature and faster color-transition. Also, higher temperature led to faster color-transition. The color-changing of PDA/amphiphilic polymer matrix may have resulted from the higher temperature and gradual insertion of amphiphilic polymer into PDA, synergistically perturbing the conformation of PDA. The prepared PDA/F127, PDA/F68, PDA/L35 and PDA/Tween-20 aqueous matrix showed potential application in time–temperature chromatic sensors at around 10–50 °C. This work provides a new method to design time–temperature chromatic sensors.