NOVELTY - Manufacture of functionalized graphene involves forming a mixture using graphite oxide, solvent and functionalized compound comprising sulfur and amino group, reacting at subcritical condition to supercritical condition of solvent, and recovering functionalized graphene.    USE - Manufacture of functionalized graphene used for barrier material, battery, electronic and electrical components, semiconductor, display, mobile telephone, high-molecular weight composite material, metal composite material, paint, paste, ink, water treatment, wastewater treatment, light material, antistatic material, static dissipative material, conductive material, electromagnetic wave shielding material, electromagnetic wave absorber, radio frequency absorber, material for solar cell, electrode material, electrical device material, electric component material, semiconductor device material, photoelectric device material, notebook computer material, personal digital assistant material, play station portable component material, game machine, transparent electrode material, field emission display material, back light unit material, liquid crystal display material, plasma display panel material, light-emitting diode material, touch panel material, display panel material, heating element, radiator, metal-plated material, catalyst, co-catalyst, oxidizing agent, reducing agent, ship component material, protective tape material, adhesive material, tray material, transportation machine component material, flame-retardant material, antibacterial material, metallic composite material, non-ferrous metal composite material, material for medical device, construction material, floor material, wallpaper material, light source material, lamp material, optical instrument component material, fiber, material for manufacturing clothes, secondary battery material, cathode active material and anode active material for secondary battery, conductive material for manufacturing electronic product, fuel cell material, solar cell material, memory device and capacitor material (all claimed).    ADVANTAGE - The method enables manufacture of functionalized graphene having excellent thermal conductivity and barrier property.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for functionalized graphene.