Encoding Bespoke Textures in Block Copolymers Using Magnetic Fields

Liquid-crystalline block copolymers (LCBCPs) self-assemble into microphase-separated structures that are magnetically anisotropic. As such, orientational order in these systems can be prescribed using a magnetic field whereby the resulting texture is governed by the balance between magnetostatics, elasticity, and interfacial block interactions. On this basis, we can program carefully designed textures (methodical arrangements of mesophase grain orientation) in these systems using patterned magnetic fields. To direct the self-assembly of the LCBCP, ferromagnetic materials are used in the presence of a weak background field to create predetermined field patterns. These fields alter the nematic director of the mesogenic material. As such, the system adopts the field-imposed structure during the microphase separation process of the diblock. We anticipate that coupling thermomechanical, thermochromic, and optical properties of LCBCPs to bespoke texture design will enable a new paradigm for geometric actuation in soft materials. This development of stimuli-responsive material, will lay a groundwork for the invention of materials with tunable properties for industries like soft-robotics, smart-wearables, and photonics.