Page 328 - MEMS and Microstructures in Aerospace Applications

Osiander / MEMS and microstructures in Aerospace applications DK3181_c014 Final Proof page 322 1.9.2005 12:47pm

322 MEMS and Microstructures in Aerospace Applications

TABLE 14.7
Properties of SU-8 34,35
Properties SU-8

Young’s modulus (GPa) 1.5 to 3.1
Yield strength (GPa) 0.03 to 0.05
Ultimate strength (GPa) 0.05 to 0.08
Thermal conductivity (W/mK) 0.2

14.6.10 CP1 1

CP1 is a fluorinated polyimide that was originally developed at the NASA Langley
Research Center as a thermal coating and later used for large thin-film concentrators
on large space-based antennas. CP1 is licensed by SRS Technologies. It is space
qualified and has a tested lifetime of 10 years. It is a transparent, low dielectric
constant, UV radiation-resistant, and moisture-resistant material developed for
high-temperature applications and is now being used to manufacture solar sails,
large antennae, solar thermal propulsion systems, and flat film panels. CP1 is
deposited by a spin on process and has been used to protect the MEMS thermal
shutters that are to be flown on Space Technology 5 (ST5). 28 Material properties of
CP1 are given in Table 14.8.

TABLE 14.8
Properties of CP1

Properties CP1
CTE 51.2 ppm/8C
Dielectric constant (at 10 GHz) 2.4 to 2.5
Film density 1.434 g/cc
Glass transition temperature 2638C
Imide IR bands 1780, 1725, and 745 cm 1
Inherent viscosity of polyamic acid (at 358C) 1.2 to 1.6 dl/g
IR emittance. Hemispherical, 300 K (coated film: aluminum) 0.03
IR emittance. Hemispherical, 300 K (uncoated film) 0.194 (0.25 mil)
Polymer decomposition temperature 5308C
Refractive index 1.58
Solar absorbance. Full spectrum (coated film. aluminum) 0.106 (0.25 ml)
Solar absorbance. Full spectrum (uncoated film) 0.072 (0.25 ml)
Specific heat. C p (at 258C) 1.094 J/g8C
Tensile modules 315 ksi
Tensile strength 14.5 ksi
UV cut off (0.2 ml film) 320 nm

© 2006 by Taylor & Francis Group, LLC