1. Inorganic Materials For Biomems Anne Samuel

2. Inorganic Materials  Materials used for micropumps and valves  Thin-Film Shape Memory Alloy(NiTi) Actuated Micropump  NiTi/Si Diaphragm Micropump  Micromachined pump based on thick-film piezoelectric actuation.

3. Thin-Film Shape-Memory Alloy Actuated Micropump  Shape memory alloys are ones which undergoes phase transformation from one phase(austenite) to an another phase( Maternsite).  Used one way shape memory effect (OWSME) for actuation.  Two actuation configurations to perform actuation- Polyimide-Spring-Biased actuator(Polyimide + TiNi) & Complementary Actuator ( TiNi+TiNi).

4. NiTi/Si Diaphragm Micropump  Micropump actuated by NiTi/Si composite diaphragm.  The recoverable force of NiTi thin film and biasing force of silicon membrane allows reciprocating motion of the pump.  Structure of a unit SMA/substrate bimorph.

5. NiTi/Si Micropump  Analysis of the actuation mechanism.  Thermal expansion coefficients of Si and SMA are different.  Depending on temperature, the bimorph structure will deform or be flat.

6. Thick-film Piezoelectric Actuation  Micropump with thick film /silicon micromachined hybrid actuation.  Actuation based on the flexure of screen printed PZT layer on Si membrane.  Schematic of hybrid actuated micropump.  Pump consists of top electrode, bottom electrode and PZT layer in the middle.

7. Thick-film Piezoelectric Actuation  Experiment with different bottom electrodes.  To find high dielectric values of PZT layer- gives good mechanical acutation performance.  It was found that Au Cermet and evaporated Pt thin film gives good dielectric constant.  Candidate in medicine as a cheap disposable pump for drug dispensing.

8. References  Bernard.W, Kahn.H et.al. “ Thin-film shape memory alloy actuated micropumps”. Journal of Microelectromechanical system.1998. Vol 7. PP 245-251.  Koch.H, Harris.N et.al. “A novel micromachined pump based on thick-film piezoelectric actuation”. Sensors and Actuators, 1998. Vol 70. PP 98-103.  Xu.D, Wang.Li, et.al. “Characteristics and Fabrication of NiTi/Si diaphragm micropump”. Sensors and Actuators, 2001. Vol 93. PP 87-92.