Highly Ordered Sub-10 nm Patterns Based on Multichain Columns of Side-Chain Liquid Crystalline Polymers

The development of nanotechnology relies crucially on the ability to fabricate materials with desired nanostructures. Because of their precise side-chain structure and versatile ordered morphologies, side-chain liquid crystalline polymers can provide a novel material platform to obtain sub-10 nm structures via their self-assembly. Here we show that for a newly designed side-chain liquid crystalline (LC) polynorbornene (P1) with a slim hemiphasmid mesogen microphase separation between the main and side chains drives the spontaneous formation of hexagonal columnar phase (Φh) composed of cylinders with a uniform diameter of 8.3 nm. At every cross section of the cylinder there are more than a dozen P1 chains laterally bundled together. The cylinders can grow axially when more chains join in becoming extraordinarily long to over several micrometers. Simple shearing can produce P1 thin films with very good orientation of the Φh phase at the macroscopic scale. More interestingly, we show that directed self-assembly of graphoepitaxy of P1 also provides an efficient route to obtain the patterned cylinders, making its applications in nanotechnology highly possible.