1. Introduction
Polydiacetylenes (PDAs) are a class of π-conjugated polymers
characterized by the presence of alternating double and triple C-C
bonds in the backbone. Their properties, such as high third-order
nonlinear susceptibility [1] and macroscopic exciton coherence
length [2], include a dramatic color transition from blue to red that
can be activated optically [3], thermally [4], mechanically [5], and
chemically [6,7]. For these properties, PDAs are receiving particular
attention as smart material to convert a wide range of external
stimuli.