To graft polymer chains from the surface, a uniform and dense initiator layer on the silicate substrate is indispensable. The initiator monolayer can be fabricated in many ways, of which self-assembly of trichlorosilanes on silicate substrates is widely used. However, uniformity is always going to be an issue when using multifunctional silanes. Although uniformity is not so problematic for monofunctional silanes, purification of the surface-active materials is difficult. To obtain a uniform initiator monolayer, an allylsilane was synthesized and used to functionalize a flat silicate substrate in this research. The allylsilane can also be purified using conventional chromatography techniques. Using AFM, the monolayer was found to be more uniform than the corresponding trichlorosilane-functionalized one. Finally, atom transfer radical polymerization was applied to graft polystyrene brushes. The ability to successfully perform sequential monomer additions was consistent with a living polymerization. Tensiometry, ellipsometry, ATR-FTIR, and AFM were used to characterize the films for each surface modification step.