Nano-pH sensor for the study of reactive materials.
We report the development of a new iridium oxide nano-pH sensor designed to work in the range of pH 3-14. The fabrication process of reproducible iridium nanotips is described. The nanotips are covered by an insulating layer of parylene to ensure a chemical insulation. The use of a gallium focused ion beam enables the opening of the apex, leading to a sensing area of 100 nm diameter. A 12 h oxidation of the iridium tip in an oxygen atmosphere gives in a stable pH response. The calibration curve in buffer solutions exhibited a Nernstian behavior (slope 59.2 mV/pH). The distance control between the sample and the nanosensor is performed by atomic force microscopy (AFM), using either a shear force control or an inverted AFM configuration. The results of the hydration of two reactive samples, tricalcium silicate and tricalcium aluminate, having a size of 50 microm only, are presented.
Ndobo-Epoy
Jean-Philippe
JP
Institut Carnot Bourgogne UMR CNRS 5209, University of Bourgogne, F-21078 Dijon, France.
Lesniewska
Eric
E
Guicquero
Jean-Pierre
JP
D006863:Hydrogen-Ion Concentration; D007495:Iridium / Q000737:chemistry; D036103:Nanotechnology
C044458:iridium oxide; D007495:Iridium