title: Highly elastic conductive polymeric MEMS.
abstract: Polymeric structures with integrated, functional microelectrical mechanical systems (MEMS) elements are increasingly important in various applications such as biomedical systems or wearable smart devices. These applications require highly flexible and elastic polymers with good conductivity, which can be embedded into a matrix that undergoes large deformations. Conductive polydimethylsiloxane (PDMS) is a suitable candidate but is still challenging to fabricate. Conductivity is achieved by filling a nonconductive PDMS matrix with conductive particles. In this work, we present an approach that uses new mixing techniques to fabricate conductive PDMS with different fillers such as carbon black, silver particles, and multiwalled carbon nanotubes. Additionally, the electrical properties of all three composites are examined under continuous mechanical stress. Furthermore, we present a novel, low-cost, simple three-step molding process that transfers a micro patterned silicon master into a polystyrene (PS) polytetrafluoroethylene (PTFE) replica with improved release features. This PS/PTFE mold is used for subsequent structuring of conductive PDMS with high accuracy. The non sticking characteristics enable the fabrication of delicate structures using a very soft PDMS, which is usually hard to release from conventional molds. Moreover, the process can also be applied to polyurethanes and various other material combinations.
authors.affiliation: Laboratory for Design of Microsystems, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Ruhhammer
authors.affiliation: Laboratory for Design of Microsystems, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Zens
authors.affiliation: Laboratory for Design of Microsystems, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Goldschmidtboeing
authors.affiliation: Gisela and Erwin Sick Chair of Micro-optics, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Seifert
authors.affiliation: Laboratory for Design of Microsystems, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Woias
keywords: antisticking; benchtop micromolding; capacitive strain gauge; conductive PDMS; highly elastic; polymeric MEMS