Rational Design of Conjugated Polymer Supramolecules with Tunable Colorimetric Responses

Polydiacetylenes (PDAs), a family of highly π‐conjugated polymers, have unique characteristics associated with their ability to self‐assemble. Disruption of the extensively delocalized enyne backbones of molecularly ordered PDA sidechains induces a blue‐to‐red color change, which has been elegantly applied in the design of chemosensors. Recently, colorimetrically reversible PDAs have received significant attention, not only to gain a better understanding of the fundamentals of PDA chromism, but also to develop methodologies to overcome limitations associated with their colorimetrically irreversible counterparts. In this article, recent progress made in the field of colorimetrically tunable (reversible, stable, or sensitive) PDAs is described. Major emphasis is given to rational design strategies developed in our group. Relevant mechanistic investigations, a diagnostic method to test colorimetric reversibility, as well as future challenges in this area will be also discussed. The rational design of thermochromic polydiacetylenes (PDAs) by manipulating strong headgroup interactions, which leads to colorimetrically tunable systems, within the authors' groups is described. In addition, a diagnostic method for assigning colorimetric reversibility to PDAs as well as an analysis of future challenges in this area is also presented.