Research on electrothermal film of graphene cellulose nanofibrils composite for wearable devices

The application of new functional materials such as graphene in the field of wearable devices has become a new trend in the future development of intelligent electronic products. In response to the insufficient flexibility of graphene based electrothermal films, this article uses Tempo-oxidized cellulose nanofibrils (CNF) rich in carboxylic acid groups to improve them. In order to prepare this graphene-CNF composite electrothermal film, ultrasonic technology was used to mix graphene with CNF, and then the film was extracted from the mixed suspension by vacuum filtration method. On this basis, further comparison and analysis of the electrothermal and mechanical properties of the film with different graphene contents are conducted. The research results indicate that the addition of CNF to the film establishes a strong interfacial bond, effectively improving the flexibility of the film. In addition, the composite electrothermal film containing 50 wt% graphene can be heated to 37 °C with only 3 V and can maintain long-term stability. The graphene-CNF composite electrothermal film prepared in this study does not require a substrate, meeting the dual requirements of flexibility and maintaining comfortable body temperature, which demonstrates a broad application prospect.