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Coupled micro electrochemistry and optics for imagery and study of chemical surface reactions
Sorin Munteanu, doctorant - PhD student Crédits : ESPCI ParisTech
Methods to monitor and quantify the chemical reactivity of surfaces at micrometer scale are developed in an optical label-free detector owing to changes in refractive index. The principle is based on the coupling between imaging techniques, optical microscopies, and micro-electrochemical techniques to study and map in real time and in situ interfacial (electro-) chemical processes. The potential of these techniques is evidenced on the mechanistic inspection of a model system: the electrochemical grafting of thin organic films on surfaces by reduction of diazonium salts.
The local (bio) chemical reactivity is examined ex situ and in situ on different gold surfaces: microelectrodes or macroelectrodes patterned either by micro contact printing or by lithography. It provides an interesting route to the inspection of the chemical reactivity of various immobilized molecules towards electrogenerated radicals. Such opto-electrochemical microscopies show that microlithography alters the reactivity of surfaces and should be handled with care when surface chemistry reaction is sought.
Finally, an analytical method based on electrochemical microscopy (SECM) allows detecting mechanical movements of a cantilever platform due to change in surface tension.