▎ 摘　　要

With the development of high-power electronics and portable devices at a noticeable rate, thermal dissipation becomes challenging and critical to the performance of these devices. It greatly promotes the research and development of thermal dissipation materials. Due to its extremely high in-plane thermal conductivity, graphene have shown great potential in thermal management. In this work, a subtle "molecular welding" strategy was realized for the fabrication of flexible, ultrathin, but highly conductive graphitized-graphene/polyimide (g-GO/PI) hybrid films. PI was applied as a solder to weld the micron-sized graphene platelets up through the covalent bonding and to fill up the voids between the graphene layers. This is believed as the key to the considerable enhancement of the in-plane thermal conductivity of g-GO/PI hybrid films. It was worth noting that an enhancement of 21.9% in the in-plane thermal conductivity was achieved for the "molecular welded" g-GO/PI hybrid film as compared to the pristine g-GO film. The proposed "molecular welding" conception provides not only a promising way to the development of the next-generation graphene-based film for thermal management, but also an effective technique to fabricate functional materials with GO or graphene nanoplatelets in other fields. (C) 2017 Elsevier Ltd. All rights reserved.