In the first half of the project we dedicated our efforts towards the synthesis and characterisation of the polymers to be used as stabilisers of graphene. We had to vary the synthesis path several times until a sufficiently high yield reaction could be found. Once the pyrene-containing polymers were ready and their characterisation complete, we aimed at the stabilisation of home-exfoliated graphene nanoplatelets (GNPs). We realised that the extent of stabilisation was highly dependent on the aspect ratio (hence number of layers) of the initial material. To fully monitor and explain the destabilisation of these hybrids with UV-light we first needed a system where the GNPs could be completely stable (extended time) before triggering the destabilisation. We decided to redesign a route where we could ensure maximal initial stability of the graphene layers, thus we chose GO. This new approach forced us to change the anchoring unit of our PDMS brushes and we introduced -NH2 functionalities instead. With these GO/PDMS hybrids we studied the photo-cleavage process in PDMS-based formulations and solvents and we were able to relate the resulting interlayer distances (before and after shining UV light) with the bulk properties of the final composites. These were then tested as strain sensors, anticorrosive coatings and dielectric actuators (before reduction of GO).
MILESTONES:
-Synthesised and fully characterised novel cleavable and non-cleavable polymer brushes based on PDMS, a photo-cleavable derivative and either pyrene or -NH2 anchoring units to stabilise graphene nanoplatelets (GNPs) and GO flakes, respectively. -Fabricated photo-responsive rGO composites
-Studied the rheological and structural properties of the rGO functionalised platelets in relation to the resulting morphology of the graphene sheets (inter-sheet spacing in a liquid crystal order or randomly oriented)
-Produced of compliant rGO/PDMS films with high barrier properties that have been successfully tested as efficient anticorrosive coatings and strain sensors
-Contributed to the consistent understanding of how the structure of graphene/polymer composites on different scales affects the bulk properties and therefore on how to design smarter materials to meet application requirements
This research programme has enabled Dr. Crespo acquiring expertise in several fields (e.g. chemical synthesis, polymer chemistry, graphene science, nano self-assembly, advanced composite processing, electroanalytical characterization), hence her multidisciplinary profile has been strengthened. The publications associated to this piece of research will impact her career very positively. MCR has created links that will be very fruitful for her next steps, as there are currently other collaboration works in process.
SILGRAFUN has contributed to accelerate the “uptake of nanotechnologies, advanced materials or advanced manufacturing and processing technologies” inthe EU. This project has contributed to keep the EU to the forefront of graphene based technologies (patent to be filed) and benefited the EU´s industry competitiveness. Furthermore, we have currently 3 publications being prepared, one of which will be ready for submission within few weeks. Once our publications are released, we will ensure maximal diffusion to help explain the societal impact that the development of new multifunctional, lightweight and nanostructured composite materials for emerging technologies has. Dr Crespo, Dr. Gaurtrot and Dr. Bilotti will ensure that the outcomes of this project are further spread in upcoming International Conferences as they have included these results in their portfolio for inciting collaborative networking.
