Non-centrosymmetric superlattices in block copolymer blends

摘要: Materials with a macroscopic electric polarization display variety of useful properties, such as piezo- and pyroelectricity second-order nonlinear optical activity1. Macroscopic results when dipolar molecules are orientated in the same direction, or ions organized non-centrosymmetric crystal structure2. Centrosymmetric have no dipole moment so cannot generate polarization. Non-centrosymmetry amorphous materials can be engineered by depositing particular sequences layers on top each other, applying external fields (generally electric) to orientate molecules3. Here we report formation structure an material through spontaneous self-assembly. Block copolymers known form ordered structures at microscale owing segregation different blocks4, 5. We show that mixture ternary triblock copolymer binary diblock will organize itself into layered which occupied blocks. The is periodic length scale around 60 nm.