Multifunctional nanomembranes self-assembled into compact rolled-up sensor-actuator devices

This paper reports on the functional principle for a rolled-up microdevice family providing the possibility to realise electrical sensor and actuator functions which are applicable to microsystem techniques, in the field of physical measuring techniques, microfluidics and biological-medical analytics. The fabrication of the roll-up devices is based on a strain-driven process converting a planar two-dimensional membrane into a three-dimensional functional element. For the realisation of these roll-up structures a broad spectrum of thin film technological approaches were used, which are well established. The special feature of these advanced microdevices consists in the possibility to design the latter's inner surface using established additive or subtractive thin film techniques. The technological route elaborated in the present work could possibly be used to realise a valve for microfluidics thanks to the combined advantages of rolled-up devices and the unique properties of temperature-sensitive hydrogels. Due to the thermal decoupling of the processed microheaters from the supporting substrate the obtained microdevices obtained are superior to conventional miniaturised planar devices in their general performance, especially in respect to the dynamical behaviour of the thermal properties. This is a prospective basis for the conceptual creation of combined sensor/actuator devices with tailored electrical and thermal properties.