Hybrid ZnO:polystyrene nanocomposite for all-polymer photonic crystals

We report on ZnO nanoparticles-polystyrene (PS) nanocomposites (NC) engineered to modify PS matrix permeability and refractive index (n), and to fabricate 1D allpolymer photonic crystals (PC) for sensing applications. The new NC can be easily processed from solutions to prepare high quality thin films by spin coating. ZnO nanoparticles (n=1.98) have been synthetized by solvothermal route and grafted with a silane to reduce phase segregation in the PS matrix (n=1.58). Such procedure led to an increase of the matrix refractive index of about 1%. By casting alternated layers of the NC and cellulose acetate (CA, n=1.46), we fabricated free-standing and flexible distributed Bragg reflectors (DBRs) of excellent optical quality. Preliminary results on the use of such DBRs as solvent vapor sensors are reported.