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In this work, a uniform hybrid film based on reduced graphene oxide, PEDOT:PSS polymer, and gold nanostructures were developed for electrochemical detection of acetaminophen—a common pharmaceutical pollutant in water environment. The electrochemical reduction of graphene oxide suspension containing hydrophilic PEDOT:PSS results in a highly uniform and compact matrix which is firmly adhered to electrode surface. Gold nanoparticles were then decorated distinctly at high density on top of that matrix to provide electro-catalytic centers for further oxidation of targeted molecules. The results on morphological characterization using scanning electron microscopy and chemical compositions in energy-dispersive X-ray spectra have demonstrated the uniformity of developed hybrid structures. It was found that the electron transfer rate was much enhanced (apparent transfer rate constant kapp was increased by 2640 times) on highly uniform AuNPs/rGO-PEDOT:PSS hybrid film. The as-prepared hybrid film was employed as transducing platform for electrochemical detection of acetaminophen at low concentrations (1–9 μM), and the detection limit was found to be as low as 532 nM. The generation of highly uniform hybrid film decorated with monodispersed metallic centers on top is essential to ensure high sensitivity in electrochemical sensing performances. [ABSTRACT FROM AUTHOR]

The resistance of a ferromagnetic cylindrical Ni nano-constriction has been measured as a function of the external magnetic field. Typical profiles of the resistance versus external field are observed with irreversible jumps separated by stable plateaus, showing systematic slow relaxation effects. An interpretation in terms of magnetomechanical strain at the level of the constriction is proposed. This scenario allows the slow relaxation behaviour to be understood in terms of displacement of dislocations or similar metastable structural defects. [ABSTRACT FROM AUTHOR]