1 Functionalization of Sulfhydryl-Terminated Monolayers on Gold and Silicon Dioxide with Polybutadiene via Thiol- ene Chemistry, and Post-Functionalization with Different Thiols, including DNA-SH Nitesh Madaan, 1 Aaron Terry, 2 John Harb, 2 Robert C. Davis, 3 Helmut Schlaad, 4 Matthew R. Linford 1 * 1 Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602 2 Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602 3 Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602 4 Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany Abstract. Self assembly of organic thiols is the most common way to introduce functional groups onto gold surfaces. And although the Au-S bond is moderately strong (~ 45 Kcal/mole), it is also prone to oxidation, which substantially weakens the Au-S interaction. In this work, we describe the creation of more robust molecular assemblies on gold. As a first step, a sulfhydryl monolayer is prepared on gold with an α,ω-dithiol. Experiments are also reported for a mercaptosilane monolayer on silicon dioxide. An oligomer of polybutadiene (PBd) was then tethered to these surfaces using thiol-ene chemistry. Residual groups on the PBd were then reacted with thiols, including octadecane thiol, perfluorinated thiols, and a thiol-terminated oligomer of DNA. Little non-specific adsorption of a non-thiolated DNA oligomer was observed. Surface characterization was performed with X-ray photoelectron spectroscopy, contact angle goniometry, secondary ion mass spectrometry, and spectroscopic ellipsometry. A thiol-gold monolayer and an analogous assembly of the same thiol tethered to gold through PBd on a dithiol monolayer were both exposed to air for two weeks and then rinsed with water. The monolayer on gold was removed in this process while the thiol in the assembly appeared unaffected.