This is a Presidential Young Investigator award. The subject of this research is the development of a relative humidity sensor based on the permittivity properties of polyimide (PI). Emphasis on the development of this sensor will be on reliability and lifetime, particularly in hostile environments. Empirical evidence indicates that prolonged condensation of water on the PI surface leads to device failure. This research will seek to characterize the expected changes in surface chemistry that may lead to reliability and aging problems. Also, the mechanical properties of PI will be characterized, particularly the thermal coefficient of expansion and swelling due to moisture, with the aim of specifying structures with reduced stress levels and greater reliability.
