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Vertical Lamellae Formed by Two-Step Annealing of a Rod–Coil Liquid Crystalline Block Copolymer Thin Film
[Image: see text] Silicon-containing block copolymer thin films with high interaction parameter and etch contrast are ideal candidates to generate robust nanotemplates for advanced nanofabrication, but they typically form in-plane oriented microdomains as a result of the dissimilar surface energies...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American
Chemical Society
2020
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7309319/ https://www.ncbi.nlm.nih.gov/pubmed/32182037 http://dx.doi.org/10.1021/acsnano.9b09702 |
Sumario: | [Image: see text] Silicon-containing block copolymer thin films with high interaction parameter and etch contrast are ideal candidates to generate robust nanotemplates for advanced nanofabrication, but they typically form in-plane oriented microdomains as a result of the dissimilar surface energies of the blocks. Here, we describe a two-step annealing method to produce vertically aligned lamellar structures in thin film of a silicon-containing rod–coil thermotropic liquid crystalline block copolymer. The rod–coil block copolymer with the volume fraction of the Si-containing block of 0.22 presents an asymmetrical lamellar structure in which the rod block forms a hexatic columnar nematic liquid crystalline phase. A solvent vapor annealing step first produces well-ordered in-plane cylinders of the Si-containing block, then a subsequent thermal annealing promotes the phase transition from in-plane cylinders to vertical lamellae. The pathways of the order–order transition were examined by microscopy and in situ using grazing incidence small-angle X-ray scattering and wide-angle X-ray scattering. |
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