writer：Wei Zhou, Peng Xiao*, and Tao Chen*
keywords：carbon nanomaterials, Janus film, flexible sensors, soft actuators, self-sensing actuators
source：期刊
specific source：Accounts of Materials Research, 2023, inpress
Issue time：2023年

Janus films have attracted widespread interest due to their asymmetric structure and unique physical or chemical properties, which demonstrate broad and blooming potential in mechanical sensing, soft actuation, energy management, advanced separation, energy conversion and storage, etc. Among them, based on the unique features of carbon nanomaterials, considerable efforts have been dedicated to exploiting carbon-based Janus films for high-performance electronic skins, soft actuators, and their integration for smart robotics. Drawn inspiration from nature, biological skins can actively perceive external physical/chemical stimuli and further perform specific motion behaviors. However, there still remain challenges of guided structural design principles, integrated multi-functions, and their efficient synergy. Specifically, their intrinsic properties and related devices performance are highly determined by the functional components coupling, surface wettability, and the controllability of the interface structures. The asymmetric combination of carbon nanomaterials and functional polymers in controllable manners can facilitate the design of high-performance sensing, actuation, and their integrated devices, which is beneficial for advancing the field of soft robotics. Therefore, it is highly significant to summarize this research area of carbon-based Janus functional films for sensing, actuating, and their integration as well as to have a deep understanding of the relationship between interfacial structures and their performance for directing future development. 

In this account, we will summarize the significant advances of carbon-based Janus films mainly conducted by our group and also contains some important reports by others. We start by introducing the general fabrication strategies for high-performance carbon-based Janus films, including physical/chemical approaches and our proposed liquid-liquid interface composite method. Among them, we carefully present the typical combination of two functional components for advanced and synergetic properties. Based on the combined designable functionality, the bioinspired artificial skins that target at sensors, actuators, self-sensing actuators, and their beyond will be discussed in detail. Finally, challenges and the prospect of structural design, structural interface, and integrated functionality will be proposed. We expect that this account would provide a better understanding of the design, fabrication, applications, and challenges of carbon-based Janus functional films and their significant potential for the development of smart robotics.