Combining Graphoepitaxy and Electric Fields toward Uniaxial Alignment of Solvent-Annealed Polystyrene–b–Poly(dimethylsiloxane) Block Copolymers

Abstract

We report a combined directing effect of the simultaneously applied graphoepitaxy and electric field on the self-assembly of cylinder forming polystyrene-b-poly­(dimethylsiloxane) block copolymer in thin films. A correlation length of up to 20 μm of uniaxial ordered striped patterns is an order of magnitude greater than that produced by either graphoepitaxy or electric field alignment alone and is achieved at reduced annealing times. The angle between the electric field direction and the topographic guides as well as the dimensions of the trenches affected both the quality of the ordering and the direction of the orientation of cylindrical domains: parallel or perpendicular to the topographic features. We quantified the interplay between the electric field and the geometry of the topographic structures by constructing the phase diagram of microdomain orientation. This combined approach allows the fabrication of highly ordered block copolymer structures using macroscopically prepatterned photolithographic substrates.

Dissipative particle dynamics for directed self-assembly of block copolymers

“…Because the feature size of the BCP self-assembled structure (sub 10nm) can be much smaller than the resolution limit of photolithography, researchers usually create relatively large trenches by photolithography, and then use these trenches to direct the BCP self-assembly to obtain uniform nanostructures with sub 10nm feature size 16,[42][43][44][45][46][47][48] . Different nanostructures such as parallel cylinders/lamellae with long-range order 44,45,47,49 , and circular cylinders 15 have been achieved by controlling the trench shape. Figure 4(a)-(d) shows the simulation results for a cylinder-forming BCP (A5B15) using a nonneutral interface and different trench shapes.…”

Thermal stability of L10-FePt nanodots patterned by self-assembled block copolymer lithography

“…To control the long-range order and orientation of the selfassembled nanostructures in BCP thin films several annealing and ordering techniques have been applied including thermal annealing [20,21], electric fields [22], the use of chemical and topographical substrate patterns [23][24][25][26], shear alignment [27] and solvent vapor annealing [28,29]. The microphaseseparated structure can be used for additive or subtractive lithography processes by typically removing one block and using the remaining structure as a mask.…”

Shaping Metallic Nanolattices: Design by Microcontact Printing from Wrinkled Stamps

“…In analogy to oPDMS, the P2VP‐OH, undergoes an annealing process after coating, during which the hydroxyl groups in the side chains of the polymeric framework of P2VP‐OH are expected to form silica esters with the Si‐OH groups on the free activated wafer surface. [ 54,55 ] Accordingly, this would result in the covalent attachment of the polymer to the substrate surface and, therefore enhance its adhesion thereon. In order to examine the chemical nature of oPDMS–P2VP substrate in more detail, XPS measurements were performed on a substrate as shown in the Supporting Information of the article (Figure S11, Supporting Information).…”