Michael Wendlandt

Nonconductive polymer microresonators actuated by the Kelvin polarization force

The authors present a method, based on the Kelvin polarization force, to actuate nonconductive polymer microstructures. A proof of principle was conducted by finite element simulations. Microresonators made of SU-8 were fabricated and characterized under resonant conditions at applied ac voltage of 5Vpp. A quality factor of Q=87 in vacuum and a square dependence of the force on the applied voltage were obtained. The presented actuator design and fabrication do not require additional electrodes on the movable structure for actuation and thus allow for the full exploration of the exceptional variety of polymer materials for microscaled actuators and sensors.

A wireless implantable passive strain sensor system

A design study of a novel passive strain-sensor technology for the in-situ measurement of small strains on implants, bones or fixation systems is presented. The sensing principle is based on hydro-mechanical strain amplification which allows for the abandonment of any electrical circuits. Thus, the sensor can be fabricated applying solely biocompatible or bioresorbable polymeric materials. Finite element simulations are employed to validate the basic sensing principle and to optimize design parameters according to the required target specifications. Remote wireless and passive signal read-out of the sensor signal can be achieved by advanced ultrasound imaging technologies