Raman Study of Polydimethylsiloxane Substrate Effect on Hydrogenation of Graphene

Raman spectroscopy is used to monitor hydrogenation of graphene on polydimethylsiloxane (PDMS) as well as on SiO₂/Si substrates. It is found that hydrogenation of graphene on SiO₂/Si is much more feasible than that on PDMS. For graphene on PDMS substrates, hydrogenation of graphene is favored on very flexible substrates. The substrate (SiO₂/Si and PDMS) and flexibility (PDMS with different flexibility) dependent hydrogenation behavior can be understood by different interactions between graphene and substrate. The interaction between graphene and SiO₂/Si is relative weak (van der Waals force) and the interaction between graphene and PDMS is relative strong, where substrate induced prestrain in the graphene layer is observed. For graphene embedded on the PDMS substrate, the more flexible the substrate is, the weaker the interaction between PDMS and graphene. The understanding of the effect of PDMS's flexibility on hydrogenation of graphene will be helpful for graphene based flexible electronics.