Additive manufacturing of arterial phantoms with integrated electroactive polymer actuators: effect of stenosis and dilation on flow characteristics

Fabrication of arterial phantoms is enabled through specially developed additive manufacturing techniques in the Organic Mechatronics and Smart Materials Laboratory to produce high resolution 3D conjugated polymer structures. These techniques have been modified to enable fabrication of arterial phantoms through the direct ink writing of polydimethylsiloxane (PDMS) into a microgel support bath. This support bath behaves as a Bingham plastic, deforming under shear stress during extrusion but quickly returning to solid-state, thus supporting the PDMS and allowing the desired structure to be maintained, producing high-resolution complex geometries. Following curing and removal of the PDMS phantom from the support bath, PEDOT:PSS thin films are selectively deposited on the phantom surface. These films have demonstrated significant hygroscopic actuation under an applied electric field. These phantoms may be imaged with Particle image velocimetry (PIV) to characterize the effect of actively changing vessel geometry. PIV can provide the instantaneous full-field velocity profile and is a well-established technique to characterize flow through phantoms fabricated by conventional casting techniques to provide a standard of comparison. To effectively image the device via PIV, the optical properties of the components must be considered. To this end, PDMS and PEDOT:PSS have been employed due to their favourable transmission properties in the visible spectrum. Additionally, PDMS provides a compliant passive structure to be deformed with relatively low force, easing the performance requirements of the actuators. While this device focuses on the actuation of phantom vessel geometry, this technique may be extended to other applications in microfluidics to create onboard peristaltic pumping action and vascular networks.