Large-scale roll-to-roll (R2R) fabrication of vertically oriented nanostructures via directed self-assembly of cylindrical block copolymer (c-BCP) thin films is reported. Nearly 100% vertical orientation of cylinders in sub-100 nm c-BCP films under optimized processing via a dynamic sharp temperature gradient field termed Cold Zone Annealing-Sharp or 'CZA-S' is achieved, with successful scale-up on a prototype custom-built 70 ft × 1 ft R2R platform moving at 25 μm/s, with 9 consecutive CZA units. Static thermal annealing of identical films in a conventional vacuum oven fails to produce comparable results. As a potential for applications, we fabricate high-density silicon oxide nanodot arrays from the CZA-S annealed BCP thin film template.

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A roll to roll continuous processing method is developed for vertical alignment ("Z" alignment) of barium titanate (BaTiO3) nanoparticle columns in polystyrene (PS)/toluene solutions. This is accomplished by applying an electric field to a two-layer solution film cast on a carrier: one is the top sacrificial layer contacting the electrode and the second is the polymer solution dispersed with BaTiO3 particles. Flexible Teflon coated mesh is utilized as the top electrode that allows the evaporation of solvent through the openings. The kinetics of particle alignment and chain buckling is studied by the custom-built instrument measuring the real time optical light transmission during electric field application and drying steps. The nanoparticles dispersed in the composite bottom layer form chains due to dipole-dipole interaction under an applied electric field. In relatively weak electric fields, the particle chain axis tilts away from electric field direction due to bending caused by the shrinkage of the film during drying. The use of strong electric fields leads to maintenance of alignment of particle chains parallel to the electric field direction overcoming the compression effect. At the end of the process, the surface features of the top porous electrodes are imprinted at the top of the top sacrificial layer. By removing this layer a smooth surface film is obtained. The nanocomposite films with "Z" direction alignment of BaTiO3 particles show substantially increased dielectric permittivity in the thickness direction for enhancing the performance of capacitors.

Many functional films including heat spreaders, ultrahigh density information storage systems, capacitors, batteries, and fuel cell membranes require enhanced through thickness properties. In this paper, we describe a design and demonstration of a multipurpose novel film formation process to orient and align functional nanoparticles and polymer phases using external electric, magnetic, and thermal gradient fields. This roll‐to‐roll processing line uses a casting system that deposits liquid film of a monomer and/or polymer solution on to a flexible substrate. Substrate is carried by belt through an electric field zone that can apply DC, AC, or a biased AC to orient the phases and particles in the vertical direction while subjecting it to UV through its built in transparent conductive carrier. To orient magnetic particles, an electromagnet located along the machine may be used. The final tool that is built on this machine is the thermal alignment zone which is designed to apply a “line of heat” oriented transverse to the machine direction at nine different zones. Using this processing line, we are able to reduce the cost of manufacturing by limiting the amount of functional fillers through directional alignment while enhancing the thickness properties. POLYM. ENG. SCI., 55:34–46, 2015. © 2014 Society of Plastics Engineers

In this study, the fast transient evolution of the electric fi eld assisted thickness Z -direction orientation and assembly of clay particles is studied using a instrumented real time system that simultaneously measures in-plane and out of plane birefringence. The optical anisotropy master curves are developed, connecting the exposure time and electric fi eld strength with orientation, using a superposition principle. Z -oriented nanocomposite fi lms manufactured through the R2R process show enhancement through thickness ionic conductivity, useful for membranes of batteries and fuel cells.