Phase-change actuators

 

Freeze/Thaw actuator

Valves and actuators are required to control fluids within microfluidic systems. When developing micro actuators and micro valves we focus on actuatores that are based on so-called phase change materials (PCM). Examples of such materials are paraffin or low melting alloys. Due to heating these materials undergo a phase change from solid to liquid state. This phase change can directly be used to close a microfluidic channel (see freeze-thaw valve).


Freeze-thaw valve

 

Shift/Gate actuator

Besides this the PCM can be used to set up bistable (latchable) actuators. This means an energy supply is only required to melt the PCM to change the current state of the actuator/microvalve.


Bistable actuator

Current research activities

 

Actuator Implementation

Based on the bistable actuator we are developing flexible actuator platforms which allows the activation of several addressable actuators/microvalves for different microfluidic applications. Potential applications are, e.g., single-cell separation out of a microfluidic flow and their selective extraction out of the system for single-cell analysis, or a device for the generation of flexible individually adaptable microfluidic channels.

 

Bistable actuator set/not set

 


Examples of bistable actuators

Associated Publications

Journal Papers

C. Richter, K. Sachsenheimer, N. Keller, T. M. Nargang, D. Helmer, F. Kotz, B. E. Rapp: "An individual addressable and latchable actuator array for microfluidic systems", Microfluid Nanofluid  20:130, 2016. | Link

C. Neumann, A. Voigt, L. Pires, B. E. Rapp: “Design and characterization of a platform for thermal actuation of up to 588 microfluidic valves”, Microfluidics and Nanofluidics, 14, 1-2, 177-186, 2012 | Link

Reviews

E. Wilhelm, C. Richter, B. E. Rapp: "Phase Change Materials in Microactuators: Basics, Applications and Perspectives", Sens. Act. A, 271, 303-347, 2018 | Link

Books and Book chapters

C. Neumann: “Entwicklung einer Plattform zur individuellen Ansteuerung von Mikroventilen und Aktoren auf der Grundlage eines Phasenüberganges zum Einsatz in der Mikrofluidik (Development of a platform for individual control of phase change based micro valves and actuators for microfluidic devices)“, KIT Scientific Publishing, Karlsruhe, ISBN: 978-3-86644-975-6, 2013 | Link

Conference Contributions

C. Richter, K. Sachsenheimer, B. E. Rapp: “A latchable thermally activated phase change actuator for microfluidic systems”, talk, SPIE Photonics West, San Francisco, USA, 2016

C. Neumann, E. Wilhelm, A. Voigt, B. E. Rapp: “A latchable thermally activated phase change actuator and optimization of its response behavior”, poster, 18th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers), Anchorage, USA, 2015

C. Neumann, E. Wilhelm, A. Voigt, B. E. Rapp: “A bistable microfluidic phase change actuator and optimization of its response times”, poster, 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), San Antonio, USA, 2014

E. Wilhelm, T. Schwarz, G. Jaworek, A. Voigt, C. Neumann, B. E. Rapp: “Bistable, tubular phase change actuators for a large scale microfluidic membrane actuator platform”, poster, 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), San Antonio, USA, 2014

E. Wilhelm, T. Schwarz, G. Jaworek, A. Voigt, B. E. Rapp: “Towards displaying graphics on a cheap, large scale Braille display”, talk, 14th International Conference on Computers Helping People with Special Needs, Paris, France, 2014

E. Wilhelm, T. Schwarz, G. Jaworek, A. Voigt, B. E. Rapp: “A refreshable Braille-Display based on a microfluidic actuation principle”, poster, Gordon Research Conference: Physics & Chemistry of Microfluidics, Lucca, Italy, 2013

C. Neumann, A. Voigt and B. E. Rapp: “A large scale thermal microfluidic valve platform”, poster, 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Seattle, USA, 2011

C. Neumann, A. Voigt, B. E. Rapp: “A large scale microfluidic thermal valve platform”, poster, Gordon Research Conference on Microfluidics, Physics & Chemistry, Boston, USA, 2011

Patents

B. E. Rapp, C. Neumann, E. Wilhelm, A. Voigt: "Bistable actuator, actuator arrangement, method for actuation and use", US9689408B2, 2017.

B. E. Rapp, L. Carneiro, A. Voigt: “Device for controlling the flow of fluids through microfluidic channels”, US8480974B2, 2013 | Link

B. E. Rapp, C. Neumann, E. Wilhelm, A. Voigt: "Bistabiler Aktor, Aktoranordnung, Verfahren zum Aktuieren und Verwendung”, DE102012005992B3, 2013 | Link

B. E. Rapp, A. Schumacher, "Vorrichtung und Verfahren zur Erzeugung oder zur Ablage eines Fluidstroms aus Fluidsegmenten und ihre Verwendung", DE102010047384B4, 2012 | Link

Miscellaneous