Novel Facial Conducting Polyamide-Based Dithiophenylidene Cyclyhexanone Moiety Utilized for Selective Cu²⁺ Sensing

The present work is aimed to synthesize a novel series of linear polyamides (PAs) 4a–d based on di(thiazolyl-thiophenylidene)cyclyhexanone as well as carries aliphatic and aromatic species in the polymer main backbones. The polymerization process was occurred by solution polycondensation technique by the interaction of the newly synthesized monomer 3 with adepoyl, sebacoyl, terphthaloyl, and isophthaloyldiacid chlorides. Before polymerization, the structure of monomer 3 was confirmed by elemental and spectral analyses. The structures of polymers were also investigated by elemental, spectral analysis, thermal analysis, and Field-Emission Scanning Electron Microscopy (FE-SEM) micrographs. Film draw temperatures for all the polymers were evaluated in the range 509.0–542.3°C. Here, the heavy metallic sensors are developed with the polyamide-fabricated glassy carbon electrode (GCE) by reliable current vs. voltage technique. A thin layer of PA onto GCE was fabricated with conducting coating agents (5% nafion) to fabricate a selective heavy metal ions, Cu2+ sensor in short response time in phosphate buffer phase. The fabricated sensor was also exhibited higher sensitivity, lower detection limit, large dynamic concentration ranges, long-term stability, and improved electrochemical performances toward Cu2+ sensor. The calibration plot is linear (r2: 0.9956) over the large Cu2+ ion concentration ranges (1.0 nM to 10.0 mM). The sensitivity and detection limit is 3.4177 µA cm−2 µM−1 and 0.36 nM (signal-to-noise ratio of 3) respectively. This novel effort is initiated a well-organized way of efficient cationic sensor improvement with conductive polymers for heavy metallic pollutants in environmental and health-care fields in large scales.