Continuously tuneable optical filters from self-assembled block copolymer blends

We demonstrate that two symmetric high molecular weight diblock copolymers, of differing molecular weights, can be blended together and subsequently shear aligned to form one photonic structure without macrophase separation. The lameller period depends on the composition of the blend and gives a photonic structure that is easily tuneable in the wavelength range (lambda(peak) = 400-850 nm).