▎ 摘　　要

In order to understand how oxidation rate of graphene surfaces affects single-stranded poly-thymine, poly(T)(20), structure during physisorption, allatom molecular dynamics simulations are performed. In aqueous solutions, poly(T)(20) is a complex structure with stacked and coiled regions. However, on the graphene surfaces, there are three different regimes for the adsorption process, which heavily depends on the surface oxidation: (1) on pristine graphene or graphene oxide (GO) with low oxygen coverage (GO 5%) the stacked poly(T)(20) structure becomes unfolded due to formation of strong pi-pi interactions with the surface, (2) on graphene oxide with moderate oxygen coverage (GO 10%-25%) the structure of poly(T)(20) is well preserved because of the balance between van der Waals and electrostatic interactions, and (3) on graphene oxide with high oxygen content (GO 30%-60%) stacked poly(T)(20) structure is locally disrupted due to formation of strong hydrogen bonds with the surface. Moreover, surface roughness due to the presence of oxygen groups plays a pivotal role in structural retention of poly(T)(20) by preventing its nucleobases from forming p-p stacking interactions with the surface.