Evidence: Well-supported that the ideal monolayer has extraordinary calculated and measured properties. Transferring those numbers onto a painted wall or a 1 Ah cell is a separate claim.
Electronic
- Linear bands near the Dirac points (1947, 2005).
- High mobility on good samples, especially encapsulated on hBN (2010, 2012).
- No native band gap in monolayer graphene. That is why digital-logic replacement of silicon stalled as an engineering ideal (2011, theories).
- Bilayers, nanoribbons, and certain stacks can open gaps — different objects.
Mechanical
- Intrinsic strength and stiffness of a pristine monolayer are among the highest measured for a 2D crystal (Lee / Hone Science 2008 nanoindentation is the usual citation). A polymer with 0.1 wt% platelets does not inherit that tensile strength.
Thermal / optical
- High in-plane thermal conductivity on clean samples; grain boundaries, wrinkles, and matrix interfaces dominate real heat-spreader products.
- Visible transparency of a monolayer is ~97.7% (Nair et al., Science 2008 is the usual optical landmark). That number made transparent-electrode pitches easy to write (2010 Bae film).
Chemical
- Basal plane is relatively inert; edges and defects are where chemistry happens. That is why a stencil on gold is about holes and edges (holey-graphene-molecular-stencil) and why GO is a different substance.
Rule for readers
Ask: which form (forms), how measured, in what matrix, at what loading. If a press release quotes the ideal monolayer next to a bulk product, that is rhetoric.