Enhancing the Stability of Polymer Nanostructures via Ultrathin Oxides Coating for Nanooptics Device Applications.

Polymer nanostructures have drawn tremendous attention due to their wide applications in nanotechnology. However, the morphology of the polymer nanostructures is fragile under harsh conditions such as high-power irradiation and organic-solution environment during the fabrication or the measurement processes, significantly limiting their potential applications. In this work, we propose and demonstrate a simple approach to improve the stability of polymer nanostructures by coating a conformal ultrathin oxide film via atomic-layer deposition (ALD). Due to the refractory and dense coating of oxides layer, the stability of polymer structures is enhanced by the prohibition of deformations occurrence from thermal-induced reflow and organic solution. As a proof of concept, PMMA nanostructures coated with sub-10-nm TiO2 layers are demonstrated, and the structures exhibit high-temperature stability at 60℃ and the good resistance of soluble damage from organic solutions. Subsequently, the mechanism of the improved thermal stability is analyzed via mechanical simulations. Such an effective approach is supposed to significantly broaden the application of polymer nanostructures as functional elements for optical structures/devices which require excellent thermal and chemical stability.