Additive manufacturing of stretchable tactile sensors: Processes, materials, and applications

3D printing technology is becoming more ubiquitous every day especially in the area of smart structures. However, fabrication of multi-material, functional, and smart structures is problematic because of the process and material limitations. This thesis sought to develop a Direct Print Photopolymerization (DPP) fabrication technique that appreciably extends the manufacturing space for the 3D smart structures. This method employs a robotically controlled micro-extrusion of a filament equipped with a photopolymerization process. The ability to use polymers and ultimately their nanocomposites in this process is the advantage of the proposed process over the current fabrication methods in the fabrication of 3D structures featuring mechanical, physical, and electrical functionalities.;In addition, this study focused to develop a printable, conductive, and stretchable nanocomposite based on a photocurable and stretchable liquid resin filled with multi-walled carbon nanotubes (MWNTs). This nanocomposite exhibited piezoresistivity, means its resistivity changes as it deforms. This property is a favorable factor in developing resistance based tactile sensors. They were also able to resist high tensile strains while they showed conductivity.;Furthermore, this study offered a possible and low-cost method to have a unique and highly stretchable pressure sensitive polymer. This disruptive pressure sensitive polymer composed of an Ionic Liquid (IL) and a stretchable photopolymer embedded between two layers of Carbon Nanotube (CNTs) based stretchable electrodes. The developed IL-polymer showed both field effect property and piezoresistivity that can detect large tensile strains up 30%.;In summary, this research study focused to present feasible methods and materials for printing a 3D smart structure especially in the context of flexible tactile sensors. This study provides a foundation for the future efforts in fabrication of skin like tactile sensors in three-dimensional motifs. This thesis sought to (1) present a capable manufacturing method to fabricate (3D) smart structures from polymers and their nanocomposites, (2) develop a stretchable, printable, and conductive Carbon Nanotube (CNT) based nanocomposite, (3) develop a stretchable, piezoresistive, and printable ionic based photopolymer.