Fabrication of carbon-based nanocomposite films by spin-coating process: An experimental and modeling study of the film thickness

Spin-coating is used for the fabrication of nanocomposite thin films, consisting of carbon nanoparticles embedded in epoxy matrix, on Mylar substrate. The final thickness of the heat-cured film was measured as a function of the spinning speed and nanoparticle concentration. Multi-walled carbon nanotubes with carboxyl functionalization (MWCNT-COOH) or exfoliated graphite nanoplatelets (xGnP) were used as fillers. Experimental results were in good agreement with the predictions from a model that considered the rheology and flow behavior of the reinforced resin fluids on a rotating disk. The model was differentiated for Newtonian and non-Newtonian regime of the spinning polymer fluid. In case of non-Newtonian behavior of the epoxy resin at high particle concentrations, a semi-empirical approach was used to determine the model constants from rheology measurements. Results from this analysis also indicate how rheological and wetting properties of the nano-reinforced polymer fluids depend on the aspect ratio of the graphene nanoplatelets.