3D Printable Vapochromic Sensing Materials

Vapochromic Coordination Polymers (VCPs) are highly stable sensing compounds that can be used for chemical sensors but require immobilization to be effective. We present a novel immobilization method for VCPs that results in a new class of Vapochromic Sensing Materials (VSMs) for chemical sensors. These VSMs can further be used as base materials for 3D printing and additive manufacturing processes to create geometrically complex sensor surfaces, or for integration with other 3D printed structures. The ammonia-sensitive VCP compound Zn[Au(CN)₂]₂ is used together with polylactic acid (PLA) to create the first type of this new class of VSM. The VSM synthesis method is simple, robust, and employs the use of the inexpensive and sustainable 3D printing polymer PLA. Early results suggest that, compared to previous methods used for the immobilization of the Zn[Au(CN)₂]₂ VCP, the VSM: 1) provides long term and stable immobilization of VCPs; 2) can detect target analytes (e.g., ammonia) at low concentrations (e.g., 5 ppm); and 3) is effective as a sensing material even when comprised of low VCP concentrations of 2% wt. or less in the PLA matrix.