Magnetic alignment of hexagonal boron nitride platelets in polymer matrix: toward high performance anisotropic polymer composites for electronic encapsulation.

We report magnetic alignment of hexagonal boron nitride (hBN) platelets and the outstanding material properties of its polymer composite. The magnetically responsive hBN is produced by surface modification of iron oxide, and their orientations can be controlled by applying an external magnetic field during polymer curing. Owing to the anisotropic properties of hBN, the epoxy composite with aligned hBN platelets shows interesting properties along the alignment direction, including significantly reduced coefficient of thermal expansion, reaching ∼28.