A macroscale, self-supporting, composite laminate sheet includes individual, layered graphene oxide sheets and a polymer in spaces between the sheets. This composite product can be fabricated by combining a suspension of individual graphene oxide sheets and a solution of polymer, passing the resulting fluid through a fluid-permeable support, and assembling the graphene oxide sheets and polymer as a laminate sheet by flow-directed assembly. The laminate is dried and released from the membrane filter as a self-supporting thin films.