Frequency- and temperature-dependent storage and loss moduli of microfibrous thin films of Parylene C

Elastic cyclic loading of ~110 mu m-thick Parylene C thin films comprising parallel slanted microfibers was performed in the frequency range 5-200Hz, to determine the dependences of their storage and loss moduli on the temperature and the frequency. The glass-transition temperature was identified as about 65 degree C from the temperature-maximum of the loss modulus. A low-frequency peak (at 115-135Hz) in the variation of the loss modulus is due to the resonance of an individual microfiber loaded by the remaining microfibers in the film.