Development of an Electrochemical Sensor for Dopamine Using Poly(4,4′‐Diaminodiphenyl Sulfone)/ TiO ₂ /Clay Nanocomposite‐Modified Glassy Carbon as Working Electrode

Structurally engineered ternary nanocomposites based on poly(4,4′‐diaminodiphenyl sulfone) (PDDS), titanium dioxide (TiO 2 ), and layered clay were successfully synthesized via in situ oxidative polymerization to develop intelligent electrochemical biosensor interfaces. Comprehensive physicochemical characterization using UV–Vis spectroscopy, X‐ray diffraction (XRD), and FE‐SEM/EDS confirmed the effective incorporation and uniform dispersion of TiO 2 nanoparticles and clay within the PDDS matrix. Structural analyses revealed enhanced semicrystallinity, modified surface morphology, and improved interfacial interactions in the ternary PDDS/TiO 2 /clay (PDDSTC) system compared to pristine PDDS and binary composites. Electrochemical investigations demonstrated significantly reduced charge‐transfer resistance ( R ct = 83.44 Ω cm 2 ) and markedly increased double‐layer capacitance ( C dl = 31.78 μF cm −2 ), indicating improved electron transport and interfacial charge storage. The PDDSTC nanocomposite exhibited superior electrocatalytic activity with wide linear detection ranges (3.81 × 10 −11 to 4.76 × 10 −6 M), excellent correlation coefficients ( R 2 = 0.997), and ultra‐low detection limits in the nanomolar range (0.0381 nM in DPV and 0.041 nM in SWV). The synergistic integration of TiO 2 and clay within the sulfone‐based conducting polymer matrix generates an optimized ternary architecture that significantly improves conductivity, adsorption capability, and electrochemical responsiveness. These findings demonstrate that structurally tuned PDDSTC nanocomposites provide a promising platform for next‐generation high‐sensitivity neurotransmitter biosensors.