Graphene
The theory of graphene was first explored by Wallace in 1947 as a starting point for understanding the electronic properties of 3D graphite. The emergent massless Dirac equation was first pointed out by Semenoff, DiVincenzo and Mele. The earliest TEM images of few-layer graphite were published by Ruess and Vogt in 1948. An early, detailed study on few-layer graphite dates to 1962 when Boehm and colleagues reported producing monolayer flakes of reduced graphene oxide. Efforts to make thin films of graphite by mechanical exfoliation started in 1990, but nothing thinner than 50 to 100 layers was produced before 2004. Initial attempts to make atomically thin graphitic films employed exfoliation techniques similar to the drawing method. Multilayer samples down to 10 nm in thickness were obtained.
Graphene oxide paper
Detailed studies of graphite oxide paper by V. Kohlschütter and P. Haenni date back to 1918. Studies of graphite oxide membranes were performed by Hanns-Peter Boehm, the German scientist who invented the term "graphene", in 1960. The paper titled "Graphite Oxide and its membrane properties" reported synthesis of "paper-like foils" with 0.05 mm thickness. The membranes were reported to be not permeable by gases (nitrogen and oxygen) but easily permeable by water vapors and, suggestively, by any other solvents which are able to intercalate graphite oxide. It was also reported that the membranes are not permeable by "substances of lower molecular weight".