Polymer droplet doesn't spread

Hello,

I am trying to observe a lubricant droplet spread on graphene but the droplet doesn’t spread. I am using all the same parameters reported in a recent publication <Sorkin, V., and Y. W. Zhang. "Wetting and spreading of long-chain ZDOL polymer nanodroplet on graphene-coated amorphous carbon." Surface Science 630 (2014): 71-77> that shows the droplet spreading.

Any ideas would be greatly appreciated.