The development of methods that permit control over the long- range order and orientation of microdomains in block copolymer (BCP) thin films for “bottom-up” approaches to nanoscale surface patterning is of great interest for many applications, including microelectronics and data storage devices. One such method recently reported, a type of zone refinement called cold zone annealing (CZA) in which the BCP film is passed across a thermal gradient, was shown to result in long-range orientational order. CZA is a versatile technique that can be combined with other approaches, such as chemical or topographic substrate patterning. Here, we utilize a combination of Rotational Small Angle Neutron Scattering (R-SANS) and specular neutron reflectivity (SNR) to investigate the mechanism and driving forces behind CZA. These unique techniques are used to characterize the 3- dimensional structural properties of zone annealed BCP films, revealing the previously unreported role of thermal gradients in controlling the kinetics and orientation of block copolymer films.
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