Novel Si/cyanate ester nanocomposites with multifunctional properties

Polymer-matrix composites (PMCs) with dispersed Si nanoparticles have been fabricated and investigated for their dielectric and mechanical properties for the first time. It is found that Si nanofillers significantly enhance the dielectric constant of the nanocomposites while preserving the low loss tangent of the Bisphenol E cyanate ester (BECy) matrix. Meanwhile, incorporation of Si nanoparticles effectively stiffens the polymer, as manifested by the large increase in the storage modulus. Furthermore, the AC conductivity of the composite is observed to decrease under compressive mechanical stresses due to the piezoresistive effect of Si. Therefore, these novel Si/BECy nanocomposites simultaneously display mechanical load-carrying, electric energy-storing and stress-sensing capabilities, very promising for multifunctional devices such as structural capacitors.