The spatially controlled functionalization of surface is currently widely investigated for several applications (biomaterials, sensors, micro/nano-fabrication, etc). Two techniques could be used to prepare such micropatterns. The first one is a photopolymerization from the surface whereas it is also possible to couple polymers onto susfaces by efficient ligation methods. Since ten years, we are working on the developement of light-sensitive alkoxyamines as a efficient method to generate alkyl and nitroxide radicals with both temporal and spatial control. The position of the chromophore is a key parameter for its use. If located on the nitroxide moiety, it will allow to perform Nitroxide Mediated Photopolymerization (NMP2). Using both mask and direct laser writting, we showed that reinitiation of a polymerization from a surface prepared using a first monomer could occur and that patterns with another monomer having different properties could be obtained. It is also possible to tune the height of the pattern with the irradiation time (microstructure thickness from few tens of nanometers to few micrometers). The influence of the nitroxide design will be highlighted in this presentation. Secondly, in recent years, several methods for the light induced formation of reactive groups on surfaces have been developed which avoid the loss of spatial resolution through diffusion of the photoactive component. Functional groups can be utilized for the highly efficient ligation of an appropriate reaction partner but require specific end-group for both partners. As the combination of alkyl radicals and nitroxides could be seen as a clean “click” reaction, we thus prepare light-sensitive alkoxyamines but with the chromophore on the alkyl moiety to selectively trigger the release of the nitroxide. Using an alkoxyamine covalently bound on surface, it is thus possible to generate patterns of nitroxides that could be coupled with a variety of alkyl radicals to prepare interesting micropatterns. The two approaches will be discussed in term of micropatterning potential.

Preparation of micro-patterned surfaces by the use of light-sensitive alkoxyamines

255th National Meeting (2018)

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