Liquid/liquid interface assisted in situ polymerisation of aniline on Ti3C2Tx MXene for electrochemical detection of dopamine

Abstract

The liquid/liquid (L/L) interface-assisted polymerisation technique, unlike bulk or single-phase polymerisation, has the potential to offer effective control of the self-assembly and diffusion of reactive intermediates and versatile tuning of the morphology at the interface to allow tailored properties within the functional nanostructures. This study adopts an in situ L/L interface-assisted polymerisation approach to generate Ti₃C₂T_x MXene/PANI with enhanced electrochemical characteristics. The aniline released at the L/L interface in a controlled manner interacts with the inherent negative charge of MXene, initiating an in situ polymerisation of PANI over the surface and interlayers of MXene to yield hydrophilic MXene/PANI nanostructures. Furthermore, their electrochemical properties are notably enhanced compared to those of hybrid structures formed via in situ single-phase polymerisation. The comprehensive research demonstrated that MXene/PANI formed at the L/L interface resulted in better exfoliation of the MXene due to the integration of fibrillar natured PANI, whereas the MXene was encased by aggregated PANI structures during single-phase polymerisation. The advancement of reactant consumption and product formation in the corresponding organic/aqueous phases was monitored using UV-visible spectroscopy, indicating controlled polymerisation at the L/L interface. The controlled release of reactants via interface circumvents side products or undesirable side-chain branching reactions, leading to the in situ generation of long-chain polymers. The successful intercalation of PANI into the interlayers of MXene was evident from physicochemical investigations such as Raman, XRD, SEM, and HRTEM. The MXene/PANI composites generated by in situ L/L interface-assisted polymerisation offered excellent electrochemical performance compared to the in situ single-phase polymerisation method. Ultimately, the synthesised nanohybrid Ti₃C₂T_x MXene/PANI-modified GCE demonstrates enhanced non-enzymatic DA sensing capabilities with a detection limit of 34 nM.