Tunable gold-chitosan nanocomposites by local field engineering

A method to control the permittivity and tunability in composite materials formed by conductive nanoparticles embedded in a flexible nonlinear dielectric matrix is proposed. The local field distributions in composite structures were determined and the field-induced permittivity was estimated for different volume fraction of conductive particles. The predicted tunability behavior agrees well with the observed trends obtained for gold nanoparticles embedded in chitosan matrix. The paper demonstrates the concept of engineered local fields in nanocomposites by using metallic nanoparticles as fillers in polymer matrix for tailoring the permittivity and tunability values.