Structural-thermochromic relationship of polydiacetylene (PDA)/polyvinylpyrrolidone (PVP) nanocomposites: Effects of PDA side chain length and PVP molecular weight

•Reversible thermochromic polydiacetylene (PDA)/poly(vinylpyrrolidone) (PVP) nanocomposites are prepared using 6 monomers.•Reversible color-transition temperature ranges from 45 to 85°C.•Alkyl chain length of PDA strongly affects the color-transition behaviors.•Increase of the PVP molecular weight results in partial reversible thermochromism.•X-ray diffraction shows intercalated structure in all systems.