Direct transformation of polycarbonate to highly conductive and superhydrophobic graphene/graphitic composite by laser writing and its applications

Polycarbonate (PC) is widely used as an important engineering polymer in numerous applications and diverse fields, ranging from optical components to building construction. Three-dimensional (3D) graphene-based material has growing interest owing to its excellent properties, impacting research fields in energy storage, biomedical, environmental applications, and more. Although laser treatment-based generation of graphene and graphitization has been demonstrated in various polymers, they have not so far been shown in PC. Here, we report that under the right conditions, industrially important material such as PC can also transformed into graphene and its properties are quite distinct from graphene generated in other organic polymers such as polyimide (PI). A 3D porous hierarchical graphene/graphitic composite structure is formed in PC due to laser treatment and it exhibited the highest electrical conductivity with a sheet resistance down to 0.8 omega sq  1 among all the laser induced graphitic (LIG) material generated using laser treatment. The unique hierarchical structure in the 3D graphene layer produces a robust and durable superhydrophobicity (contact angle at 170.6 degrees +/- 8.8 degrees) in the ambient environment. We demonstrate integration of gold nanoparticles into the graphene layer using the same single step laser treatment for its application as a glucose sensor, and also demonstrate its other applications for direct integration of contact electrode of a chemiresistive sensor, a temperature sensor, and as an electrical heater on insulating materials. Since PC is such an important and widely used industrial plastic, these integration methods are of broad applicability to instrument components made of PC directly.