Photochemistry highlights on-surface synthesis

International audienceOn-surface chemistry is promising way in order to achieve the bottom-up construction of covalently-bonded molecular precursors into extended atomically-precise polymers adsorbed on surfaces. These polymers exhibit unprecedented physical or chemical properties which are of great interest for various potential applications. The fabrication of these nanostructures was mainly obtained in ultrahigh vacuum (UHV) environment on single-crystal surfaces, i. e. noble metal surfaces, by thermal annealing as stimulus to provoke the polymerisation with a "catalytic" role of the surfaces adatoms. Nevertheless, photons are also a powerful source of energy to induce the formation of covalent architectures, even if it is less-used on surfaces than in solution. In this minireview, we discuss the photoinduced on-surface polymerization from the basic mechanisms of photochemistry to the formation of extended polymers on different kinds of surfaces which are characterized by scanning probe microscopies

Droplet ejector using Surface Acoustic Waves.

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A love-wave sensor for direct detection of biofunctionalized nanoparticles

In this work, we have designed and manufactured Love wave sensors equipped with a liquid cell for the detection of bio-functionalized nano-particules in water. Measurements using these devices are based on the determination of velocity and propagation loss changes of a guided acoustic shear wave generated by Inter-Digital Transducers (IDTs) patterned on a (YX1t)/36 degrees/90 degrees cut of quartz and passivated by a silica overlay. The so-called Love mode acoustic wave sensors are known to he compatible with operation in liquid medium but requires and adapted fluidic packaging. The SU-8-based liquid cell is patterned atop the SiO2 guiding layer. We then describe the use of these sensors for the time resolved identification of the presence of nanoparticles in suspension. Silane surface chemistry for non-selective detection of most bio-functionalized nanoparticles health hazards is demonstrated by analyzing the gravimetrie signal associated with the binding of avidin-functionalized gold nanoparticles

Adsorption of zwitterionic assemblies on Si(111)-7 × 7: A joint tunneling spectroscopy and ab initio study.

The adsorption of zwitterionic molecules on Si(111)-7×7 substrates has been probed by scanning tunneling microscopy and spectroscopy and studied via density-functional-theory calculations. Experimental results obtained at room and low temperatures revealed the reconstruction of Si(111)-7×7 half-cells with molecular constructs accommodating three zwitterions. A structural model for the inscription of the Si(111)-7×7 half-cell with zwitterionic edifices is proposed and the nature of the interactions between the molecular assemblies and the surface is established thanks to joint experimental data and simulations