Diethyl-modified polydimethylsiloxane polymer-fluid-gels: Breakthrough of damping limits at ultra-low temperatures or ultra-high frequencies

Polymeric damping materials with a wide temperature or frequency range present significant challenges, especially when used for vibration attenuation at ultra-low temperatures or ultra-high frequencies, as the chain motions are frozen in these extreme environments. In our previous studies, polydimethylsiloxane (PDMS) polymer-fluid-gels (PFGs) dampen vibrations over a relatively wide temperature or frequency range; however, their lower-temperature limit is-55 degrees C, and their upper-frequency limit is about 150 Hz due to the symmetry and regularity of dimethylsiloxane molecular structure. In this work, the regularity is broken by introducing the second monomers of hexaethylcyclotrisiloxane, and diethyl-modified polydimethylsiloxane (PEMS) PFGs with 20 % diethyls are prepared, breaking through the effective damping limits of ultra-low temperature to-123 degrees C and ultra-high frequency to 1010 Hz. Ultra-low temperature (about-120 degrees C) experiments show that the falling ball impact absorption capacity of the PEMS PFGs is over 2500 % and 1400 % higher than that of commercial silicone rubber (Sylgard 184) and the PDMS PFGs. Ultra-high frequency tests demonstrate that PEMS PFGs can completely attenuate ultrasonic shocks of 40 kHz, while Sylgard 184 and the PDMS PFGs can't suppress vibrations of such high frequency.