Orthogonal polydiacetylene (PDA) derivatives based optical chemsensors for the selective detection of cyanide

Due to its widespread usage but high toxicity, the detection of cyanide has drawn special attention. However, in many works usually only one colorimetric or fluorescent detector was put forward for chemical sensing. Here in this contribution, two kinds of polydiacetylene (PDA) derivatives substituted by either o-hydroxybenzaldehyde or dicyanovinyl group were designed and explored for the optical sensing of cyanide. Firstly, these two PDA derivatives were polymerized in the form of vesicle individually and showed chromatic transition from blue to purple or red after the addition of cyanide into the aqueous solution. Then polyvinylidene fluoride membrane was chosen to incorporate the PDAs to form strip-based solid sensors, which could exhibit obvious blue-to-red colorimetric response upon exposure to cyanide aqueous solution with different concentrations in an orthogonal way. Interestingly, these two PDA derivatives remained blue phase in the presence of many common anions, thus demonstrating excellent selectivity for the distinguishment of cyanide. Besides the experimental characterization methods, such as UV–visible absorption and Raman spectroscopy, to study the underlying chemical mechanism, the principal component analysis method was also applied for the multivariate statistical analysis in combination with RGB (Red, Green, Blue) values to obtain a deep insight into the chromatic sensing of PDAs.