Seminar 2/9/2011: Enabling Complex 3-D Geometries of Stretchable Electronics using Shape Memory Polymers
Professor Walter Voit
Department of Materials Science and Engineering, Department of Mechanical Engineering
University of Texas at Dallas
A class of dynamic, smart materials called shape memory polymers (SMP's) has been used for interfacing with metallic conductors, to create devices that change in stiffness as a function of temperature or environmental condition. Current efforts seek to pattern devices onto customized polyacrylic substrates of complex 3-D geometries. The copolymers are polymerized in a free radical chain-growth polymerization under 365 nm UV light which allows control of the substrate's thermomechanical properties. Using the shape memory effect enables standard lithographic processing on these (temporarily) flat surfaces, which then can recover (permanently) to new complex shapes.
A competing effort seeks to make use of a new manufacturing process utilizing ionizing radiation to post-crosslink polymers after fabrication in flat form. This novel manufacturing process is called Mnemosynation. I will demonstrate polyacrylic SMP samples tuned to possess glass transition temperatures (Tg's) ranging between 20 and 120 ÃÂ°C (i.e., from well below to well above human body temperature). I will further show samples with tailored recoverable force tuned by altering rubbery modulus between 0.5 and 13 MPa. These substrates exhibit thermosetting shape-memory properties: low residual strains, tunable recoverable force, adjustable Tg , and complex 3-D shapes. Coupling these customizable mechanical properties of shape memory polymers with traditional plastic processing techniques enables a new generation of mass producible plastic products for flexible electronics. Neural brain probes, flexible transistors, cell culture dishes, cochlear implants and flexible prosthetics are just a few examples.
Host: Sigurd Wagner, Electrical Engineering
Location: Bowen Hall Auditorium
Date/Time: 02/09/11 at 12:00 pm - 02/09/11 at 1:00 pm
Category: PRISM/PCCM Seminar Series