Shape Change Technologies holds patents on the most effective
and consistent processes for manufacturing thin film.
We can make films to suit your specific applications. TiNi alloys have already been space qualified and are Class 3 biomaterials which simplifies matters in terms of research. We have sputtered film on Si, SiO2, SiN, glass, and polymer substrates. We also able to release the TiNi from substrate to produce a free-standing film. In addition, we have developed methods of patterning our TiNi film giving us the ability to fenestrate films and create complex 2D shapes. We have utilized these techniques for a variety of applications.
SHAPE MEMORY ALLOY (SMA) MICROPUMPS
The MEMS community has been interested in using thin film nickel titanium alloys for microactuators because of the large forces (600 MPa) and displacements (8%) they generate. Alternative technologies such as electrostatics, electromagnetics, and piezoelectrics do not produce a tenth of the forces and displacements sputtered TiNi can. Furthermore, the technology can be easily integrated into current silicon micromachining processes.
ADAPTIVE OPTICS
A thin film of nickel titanium can be sputtered directly onto polymeric membranes to produce lightweight correctable optical mirrors for surveillance telescopes. What makes TiNi, and shape memory alloys in general, attractive over other "smart" actuator materials is their unique ability to produce large strains (up to 8%). Piezoelectric and magnetostrictive materials are brittle and can only withstand 0.2% strain. This makes conformal integration of actuators challenging. Moreover, the operating temperature ranges of these materials are narrow compared to that of shape memory alloys and their sensitivity to stray electric and magnetic fields makes integration even more problematic. Electroactive polymers are emerging as candidates for these types of applications; however, they have a slow response and exert small forces. These limitations along with its sensitivity to stray electric fields make their use as shape correction membranes implausible.
HEART VALVE LEAFLETS
Nickel titanium (Nitinol) stents have long been used to prop open occluded arteries because of their biocompatibility and unique mechanical properties. Shape Change Technologies has started research on a TiNi heart valve that can be deployed like stents. The initial step of the research was to create the valve leaflets out of our sputtered thin film. We were successful in producing several free-standing fenestrated leaflets using standard photolithography and etching methods. The fenestrations allow us to adjust to stiffness of the implant to match the stiffness of the heart valve tissue. Currently, tests are being performed on the leaflets to determine its fatigue limits. A picture of one of our fenestrated leaflets is shown on the upper right portion of this webpage. Click here to read a paper on the biocompatibility of our sputtered TiNi films.
