Study of the kinetics and mechanism of rapid self-assembly in block copolymer thin films during solvo-microwave annealing

Show simple item record Mokarian-Tabari, Parvaneh Cummins, Cian Rasappa, Sozaraj Simao, Claudia Sotomayor Torres, Clivia M. Holmes, Justin D. Morris, Michael A. 2016-02-10T18:05:30Z 2016-02-10T18:05:30Z 2014-08-19
dc.identifier.citation MOKARIAN-TABARI, P., CUMMINS, C., RASAPPA, S., SIMAO, C., SOTOMAYOR TORRES, C. M., HOLMES, J. D. & MORRIS, M. A. 2014. Study of the Kinetics and Mechanism of Rapid Self-Assembly in Block Copolymer Thin Films during Solvo-Microwave Annealing. Langmuir, 30, 10728-10739. en
dc.identifier.volume 30 en
dc.identifier.issued 35 en
dc.identifier.startpage 10728 en
dc.identifier.endpage 10739 en
dc.identifier.issn 0743-7463
dc.identifier.doi 10.1021/la503137q
dc.description.abstract Microwave annealing is an emerging technique for achieving ordered patterns of block copolymer films on substrates. Little is understood about the mechanisms of microphase separation during the microwave annealing process and how it promotes the microphase separation of the blocks. Here, we use controlled power microwave irradiation in the presence of tetrahydrofuran (THF) solvent, to achieve lateral microphase separation in high- lamellar-forming poly(styrene-b-lactic acid) PS-b-PLA. A highly ordered line pattern was formed within seconds on silicon, germanium and silicon on insulator (SOI) substrates. In-situ temperature measurement of the silicon substrate coupled to condition changes during "solvo-microwave" annealing allowed understanding of the processes to be attained. Our results suggest that the substrate has little effect on the ordering process and is essentially microwave transparent but rather, it is direct heating of the polar THF molecules that causes microphase separation. It is postulated that the rapid interaction of THF with microwaves and the resultant temperature increase to 55 degrees C within seconds causes an increase of the vapor pressure of the solvent from 19.8 to 70 kPa. This enriched vapor environment increases the plasticity of both PS and PLA chains and leads to the fast self-assembly kinetics. Comparing the patterns formed on silicon, germanium and silicon on insulator (SOI) and also an in situ temperature measurement of silicon in the oven confirms the significance of the solvent over the role of substrate heating during "solvo-microwave" annealing. Besides the short annealing time which has technological importance, the coherence length is on a micron scale and dewetting is not observed after annealing. The etched pattern (PLA was removed by an Ar/O-2 reactive ion etch) was transferred to the underlying silicon substrate fabricating sub-20 nm silicon nanowires over large areas demonstrating that the morphology is consistent both across and through the film. en
dc.description.sponsorship Science Foundation Ireland (SFI CSET/CRANN); European Commission (LAMAND NMP FP7) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher American Chemical Society en
dc.rights © 2014 American Chemical Society. This document is the Submitted Manuscript version of a Published Work that appeared in final form in Langmuir, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see en
dc.subject PS-b-PMMA en
dc.subject Diblock copolymers en
dc.subject Low temperatures en
dc.subject Polystyrene en
dc.subject Orientation en
dc.subject Polylactide en
dc.subject Diffusion en
dc.subject Silicon en
dc.subject Arrays en
dc.title Study of the kinetics and mechanism of rapid self-assembly in block copolymer thin films during solvo-microwave annealing en
dc.type Article (peer-reviewed) en
dc.internal.authorcontactother Justin D. Holmes, Chemistry, University College Cork, Cork, Ireland. +353-21-490-3000 Email: en
dc.internal.availability Full text available en 2014-10-21T11:17:22Z
dc.description.version Submitted Version en
dc.internal.rssid 274158549
dc.contributor.funder Science Foundation Ireland en
dc.contributor.funder European Commission en
dc.description.status Peer reviewed en
dc.identifier.journaltitle Langmuir en
dc.internal.copyrightchecked No. !!CORA!! The Accepted Manuscript may be posted to the repository 12 months after online publication with a set statement. en
dc.internal.licenseacceptance Yes en
dc.internal.IRISemailaddress en

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