Selective Actuation of Polymer Nanocomposites by Controlling Properties of Magnetic and Plasmonic Nanoparticles for Soft Robotics Application

The field of soft robotics is associated with soft materials that are amenable to reshaping, which encompasses a broad range of material systems -- in terms of both their composition and structural design. Commonly employed materials include elastomers, hydrogels, thermoplastics or their composites with other functional "hard" materials. These hard materials allow for actuation of their soft matrices using mechanical, chemical, magnetic, or electrical stimuli. Polymer nanocomposite (PNC) actuators for soft robotics combine the elastic properties of the matrix with the functional response of nanoparticles (NPs). The response of these actuators can be tuned by the functionality and physical properties of the nanoparticles as well as by their arrangement within. The focus of this dissertation is to devise such systems where selective actuation of a polymer nanocomposite is achieved by controlling one or more of the above factors.;The experiments establish the proof of concept for the various techniques to achieve actuation in selected polymers. Specifically, systems with two different sets of nanoparticles were studied: magnetic and plasmonic nanoparticles. One-dimensional (1D) arrangement of magnetic particles into chains imparts anisotropic magnetic properties to the resulting composite, which has been utilized to obtain an anisotropic mechanical response. This selectivity in actuation was shown to be present in uniform field as well as magnetic field gradients. A model was also designed to describe the actuation behavior for simple bending experiments.;In the second project, plasmonic nanoparticles were incorporated into shape memory polymers, which allowed shape recovery by photothermal heating. By using two different sets of plasmonic NPs and using the light source with the correct wavelength corresponding to one of the NPs, selective heating and therefore selective recovery was obtained. This is useful for designing sequential or selective actuators from the same composite.;An electrospinning setup was designed and fabricated to obtain nanoscale fibers of different materials. Collaborative projects were undertaken to incorporate interesting nanomaterials in electrospun fibers.;The overall goal of this research is to lay the groundwork towards development of more advanced soft robotic actuators based on functional polymer nanocomposites.