Non-centrosymmetric superlattices in block copolymer blendsстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Materials with a macroscopic electric polarization display a variety of useful properties, such as piezo- and pyroelectricity and second-order nonlinear optical activity1. Macroscopic polarization results when dipolar molecules are orientated in the same direction, or when ions are organized in a non-centrosymmetric crystal structure2. Centrosymmetric molecules have no dipole moment and so cannot generate a macroscopic polarization. Non-centrosymmetry in amorphous materials can be engineered by depositing particular sequences of layers on top of each other, or by applying external fields (generally electric) to orientate the
molecules. Here we report the formation of a non-centrosymmetric structure in an amorphous material through spontaneous selfassembly. Block copolymers are known to form ordered structures at the microscale owing to segregation of the different blocks.We show that a mixture of a ternary triblock copolymer and a binary diblock copolymer will organize itself into a noncentrosymmetric layered structure in which the layers are occupied by different blocks. The structure is periodic with a length scale of around 60 nm