Abstract
Electroactive polymers are an emerging class of smart materials, comprising piezoelectric and conductive materials besides others. These materials present us with features of interest such as properties of electrical conduction in conductive polymers and electromechanical coupling in piezoelectric polymers where they undergo deformation in the presence of external electric field and vice-versa. The electroactive nature of these soft materials offers the potential to tune its properties for the next-generation applications in robotic sensors, wearable electronics, and energy harvesting. External electric field can be leveraged to fabricate desired structures of electroactive polymer scaffolds and structures in quasi 3D (electrospun micro/nano fiber mat scaffold) and 3D configuration. Furthermore, we aim to understand the influence of the processing conditions, and the electric field on the properties of the fabricated structures.Polyaniline, a conjugated conductive polymer, is used to obtain conductive solution blends with polymers such as PCL and gelatin. Doped PANI (with CSA) is blended with PCL and gelatin to obtain polymer solutions that can undergo stretching under an applied external electric field. Electrospinning of PANI/PCL/gelatin blend produced nanofiber mats suitable for studying OPCs as the model system for cells in electrically stimulated environments. The cell viability after 24h in the proliferation stage followed by 24h in the differentiation phase reveal the potential as axon mimics and further studies in electrical stimulation of cells. However, the conductivity of PANI/PCL/gelatin nanofiber mats is limited, while the PANI/PCL nanofiber mats were conductive with a significant improvement in conductivity.Polyvinylidene fluoride (PVDF) is a soft, piezoelectric material and its sensitivity to electrical fields is mainly due to its ß-crystalline phase and oriented dipoles. 3D electroprinting is a promising approach for creating 3D PVDF piezoelectric devices, as it allows for the improvement of PVDF's electroactive crystalline phases through mechanical stretching and electrical poling. This study found that adding an anti-solvent to the PVDF solution was key in obtaining optimal solution viscosity and solvent evaporation rate for layer-by-layer printing. The resolution of the printed structure was also affected by nozzle-to-collector distance and extrusion pressure. Results showed that freestanding 3D PVDF structures with average layer heights as small as 30 µm and the ability to continuously print multiple 3D designs were achievable. Analysis using FTIR and XRD spectra showed improved electroactive ß and ? phases in the electroprinted PVDF compared to the dominant a phase in PVDF powder. The 3D PVDF structures were sensitive to different load profiles and frequencies.