Plasma Time and Power Sequence Impact on Wettability Tuning and Mechanical Properties of Fluorinated Monolayer Graphene

Fluorinated graphene is an up-rising member of the graphene family and attracts significant attention since it is a ۲D layer-structure, is self-lubricating, has wide bandgap and high thermal and chemical stability. By adjusting the C–F bonding character and F/C ratios through controlled fluorination processes, fluorinated graphene can be utilized for a wide range of applications including energy conversion, storage devices, bio- and electrochemical sensors. Herein, monolayer CVD graphene/Cu was fluorinated via SF۶ plasma with time and power sequence trial. Structural, morphological, roughness, adhesive forces, and wettability of fluorinated graphene was explored. Insight was gained by Raman spectroscopy, SEM and EDS, surface roughness and adhesive force measurements via AFM on different samples. Fluorination produced p-doped structure, blue shift in the ۲D peak and red shift in D peak of the Raman spectra of graphene. Increase in plasma time increased the defects and weakened C-C bonds much more rapidly at higher plasma power (۴۰W) while lower plasma power (۱۵W) retained more of graphene properties (having high La, LD and low nD) confirmed by Raman, SEM and EDS analyses. Surface roughness and adhesive forces on graphene surface were mostly increased with the increase in plasma time at a certain power. Higher plasma power resulted in more hydrophobic surfaces and even the wettability tuning occurred in the hydrophobic regime while lower plasma power demonstrated tuning in the hydrophilic regime. Influence of the underlying surface and π -electron pairs were shown to play more significant roles in tuning the wettability at higher plasma power.

کلیدواژه ها:

Graphene ، Fluorination ، Raman ، Surface roughness ، adgesive force