Solid-like dynamics in ultrathin films of polymeric liquids
Saraf, Ravi F.
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In this letter, we demonstrate that, at mesoscales, nonferroelectric liquid films of poly(dimethyl siloxane) exhibit significant electrostriction not present in the corresponding bulk state. Remarkably, the observed electrostrictive effect has a response time <20 mus in contrast to >5 ms recorded in conventional bulk (ferroelectric) polymers. The emergence of this fast electrostrictive strain in thin films is explained in terms of the amalgamation of two contrasting dynamic features-the influence of a highly mobile, viscous layer (at the air/film interface) on the less-mobile, but fast responding, solid-like layer at the film/substrate interface. The effect is observed for thickness below 200 nm. (C) 2003 American Institute of Physics.