Reaction of isocyanate-functionalised silicon wafers with complex amino compounds

A feasible method of grafting complex amine structures (methyl ester of glycine, Rho-Lys-Arg-NH2, amine-terminated oligonucleotide and 7,8,11,12-tetrahydro-5-hexahelicenamine) onto a silicon wafer surface is described. The two step process comprises (1) anchoring 10-isocyanatodecyl-trichlorosilane to a 1.8-2-nm thin silica layer on a single silicon wafer crystal (100) and (2) the attachment of amine substrates through a urea linkage by reacting those with isocyanate groups on the wafer surface. Both steps can be monitored by ATR FTIR showing the appearance/disappearance of the isocyanate band. Measuring the contact angles along with the AFM imaging of the surfaces indicated the formation of the monolayers. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim Germany, 2007).