Polydiacetylenes

In addition, many PDAs exhibit thermochromism caused by twisting of the polymer backbone, changing the amount of conjugation in the system.

Upon exposure to the external stimuli such as thermal, chemical and mechanical stimulus, the conjugation effect will endow the chromatic properties to this type material.

As far as the pure or "intrinsic" PDAs are concerned, the blue to red phase transition is irreversible, however if the head groups of the PDAs' side chain are strengthened by other structure, for example chelation with metal oxide nanoparticles, it could provide resilience of the backbone to conduct the reversible color change.

[7] Several recent researches which assisted by DFT simulation have shown that the chromatic properties could be modified by adjusting the side chain structures of PDA.

[9][10] Zhu et al. have recently published an article about the synthesis of polydiacetylene using copper catalyst.