UV-solvent annealing for morphology and orientation control in self-assembled PS-PDMS thin films

The response of polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS) thin films to UV exposure during solvent vapor annealing is described, in order to improve their applicability in nanolithography and nanofabrication. Two BCPs were examined, one with the PS block as majority (f[subscript PS] = 68%...

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Bibliographic Details
Main Authors: Ntetsikas, K, Liontos, G, Avgeropoulos, A, Lee, Keehong, Kreider, Melissa E., Bai, Wubin, Cheng, Li-Chen, Dinachali, Saman Safari, Tu, Kun-Hua, Huang, Tao, Ross, Caroline A
Other Authors: Massachusetts Institute of Technology. Department of Chemical Engineering
Format: Article
Published: IOP Publishing 2017
Online Access:http://hdl.handle.net/1721.1/111947
https://orcid.org/0000-0002-8554-6998
https://orcid.org/0000-0001-9975-9903
https://orcid.org/0000-0003-0559-8219
https://orcid.org/0000-0003-2262-1249
Description
Summary:The response of polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS) thin films to UV exposure during solvent vapor annealing is described, in order to improve their applicability in nanolithography and nanofabrication. Two BCPs were examined, one with the PS block as majority (f[subscript PS] = 68%, M[subscript n] = 53 kg mol⁻¹), the other with PDMS block as majority (f[subscript PDMS] = 67%, M[subscript n] = 44 kg mol⁻¹). A 5 min UV irradiation was applied during solvent vapor annealing which led to both partial crosslinking of the polymer and a small increase in the temperature of the annealing chamber. This approach was effective for improving the correlation length of the self-assembled microdomain arrays and in limiting subsequent flow of the PDMS in the PDMS-majority BCP to preserve the post-anneal morphology. Ordering and orientation of microdomains were controlled by directed self-assembly of the BCPs in trench substrates. Highly-ordered perpendicular nanochannel arrays were obtained in the PDMS-majority BCP.