We study the decay of the imprinted polystyrene (PS) patterns under thermal annealing using light diffraction. The first order diffraction intensity from the imprinted gratings was measured as a function of annealing time. Local intensity maximum is observed as a function of annealing time. This abnormal intensity variation can be qualitatively understood, using Rigorous Coupled Wave Approximation (RCWA) calculations, as a characteristic diffraction from patterns with certain shape/height. We demonstrate that diffraction anomaly can be used to characterize the temperature dependence of the decay rate. The activation energies of the pattern decay are found to be similar to that of the segmental and chain relaxations. Comparisons between different molecular weight PS samples reveal that the patterns decay through different mechanisms.
Citation: ACS Nano
Pub Type: Journals
nanoimprint, pattern decay, relaxation, stability, thermal embossing