Surface Patterning

U. Jonas

Chemical patterning of surfaces is a major route to the preparation of surface structures down to nanometer dimensions and several strategies have been described in the literature. Among these, patterning by light is particularly attractive, because light can be easily generated and controlled. For the efficient interaction of light with molecular surface layers it is advantageous to include specific photosensitive moieties directly in surface-active molecules like thiols or silanes. For this purpose silanes with photosensitive protecting groups were synthesized prior to monolayer preparation, which represents a major improvement over existing patterning strategies. Complex combinations of different functional and protecting groups can be introduce into the surface layers by simultaneous coadsorption of the corresponding silane mixtures. This was demonstrated by mixing silanes with photoactive nitroveratryl and benzoin derivatives, which can be cleaved individually by irradiation with light of different wavelengths (253 and 411 nm). The resulting chemical contrast can be used to direct assembly of colloids or fluorescence dyes to the activated areas. This new method offers, e.g., the possibility of selective immobilization of DNA fragments for biochip applications.

C.A. Fustin, G. Glasser, H. W. Spiess, U. Jonas: "Parameters Influencing the Templated Growth of Colloidal Crystals on Chemically Patterned Surfaces”, Langmuir 20, 9114-9123 (2004).
A. del Campo, D. Boos, H. W. Spiess, U. Jonas: “Surface Modification with Orthogonal Photosensitive Silanes for Sequential Chemical Lithography and Site-Selective Particle Deposition”, Angew. Chem. Int. Ed. 44, 4707-4712 (2005).