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Neppalli SN, Collins TW, Gholamvand Z, Cummins C, Morris MA, Mokarian-Tabari P. Defining Swelling Kinetics in Block Copolymer Thin Films: The Critical Role of Temperature and Vapour Pressure Ramp. Polymers (Basel) 2021; 13:4238. [PMID: 34883741 PMCID: PMC8659708 DOI: 10.3390/polym13234238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/26/2021] [Accepted: 11/30/2021] [Indexed: 11/25/2022] Open
Abstract
We studied the kinetics of swelling in high-χ lamellar-forming poly(styrene)-block- poly(lactic acid) (PS-b-PLA) block copolymer (BCP) by varying the heating rate and monitoring the solvent vapour pressure and the substrate temperature in situ during solvo-thermal vapour annealing (STVA) in an oven, and analysing the resulting morphology. Our results demonstrate that there is not only a solvent vapour pressure threshold (120 kPa), but also that the rate of reaching this pressure threshold has a significant effect on the microphase separation and the resulting morphologies. To study the heating rate effect, identical films were annealed in a tetrahydrofuran (THF) vapour environment under three different ramp regimes, low (rT<1 °C/min), medium (2
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Affiliation(s)
- Sudhakara Naidu Neppalli
- School of Chemistry, The University of Dublin, Trinity College Dublin, D02 PN40 Dublin, Ireland; (S.N.N.); (Z.G.); (M.A.M.)
- Advance Material and BioEngineering Research (AMBER) Centre and CRANN, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Timothy W. Collins
- Department of Chemistry, University College Cork, Tyndall National Institute, T12 K8AF Cork, Ireland;
| | - Zahra Gholamvand
- School of Chemistry, The University of Dublin, Trinity College Dublin, D02 PN40 Dublin, Ireland; (S.N.N.); (Z.G.); (M.A.M.)
- Advance Material and BioEngineering Research (AMBER) Centre and CRANN, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Cian Cummins
- Centre de Recherche Paul Pascal (CRPP), The French National Centre for Scientific Research (CNRS), University of Bordeaux, UMR 5031, 115 Avenue Schweitzer, 33600 Pessac, France;
- Laboratoire de Chimie des Polymeres Organiques (LCPO), University of Bordeaux, CNRS, Bordeaux INP, 16 Avenue Pey-Berland, CEDEX, 33607 Pessac, France
| | - Michael A. Morris
- School of Chemistry, The University of Dublin, Trinity College Dublin, D02 PN40 Dublin, Ireland; (S.N.N.); (Z.G.); (M.A.M.)
- Department of Chemistry, University College Cork, Tyndall National Institute, T12 K8AF Cork, Ireland;
| | - Parvaneh Mokarian-Tabari
- School of Chemistry, The University of Dublin, Trinity College Dublin, D02 PN40 Dublin, Ireland; (S.N.N.); (Z.G.); (M.A.M.)
- Advance Material and BioEngineering Research (AMBER) Centre and CRANN, Trinity College Dublin, D02 PN40 Dublin, Ireland
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Rejek T, Schweizer P, Joch D, Portilla L, Spiecker E, Halik M. Buried Microphase Separation by Dynamic Interplay of Crystallization and Microphase Separation in Semicrystalline PEO-Rich PS- b-PEO Block Copolymer Thin Films. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tobias Rejek
- Organic Materials and Devices, Institute of Polymer Materials, Department of Materials Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
| | - Peter Schweizer
- Institute of Micro- and Nanostructure Research & Center for Nanoanalysis and Electron Microscopy (CENEM), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
| | - Daniel Joch
- Organic Materials and Devices, Institute of Polymer Materials, Department of Materials Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
| | - Luis Portilla
- Organic Materials and Devices, Institute of Polymer Materials, Department of Materials Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
| | - Erdmann Spiecker
- Institute of Micro- and Nanostructure Research & Center for Nanoanalysis and Electron Microscopy (CENEM), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
| | - Marcus Halik
- Organic Materials and Devices, Institute of Polymer Materials, Department of Materials Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
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Mokarian-Tabari P, Cummins C, Rasappa S, Simao C, Sotomayor Torres CM, Holmes JD, Morris MA. Study of the kinetics and mechanism of rapid self-assembly in block copolymer thin films during solvo-microwave annealing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10728-10739. [PMID: 25137566 DOI: 10.1021/la503137q] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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-χ 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 °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/O2 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.
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Rice RH, Mokarian-Tabari P, King WP, Szoszkiewicz R. Local thermomechanical analysis of a microphase-separated thin lamellar PS-b-PEO film. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:13503-11. [PMID: 22924663 DOI: 10.1021/la302565s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We use atomic force microscopy (AFM) and hot tip AFM (HT-AFM) to thermophysically characterize a 30 nm thick film of poly(styrene-block-ethylene oxide), PS-b-PEO, and to modify its lamellar patterns having spacing of 39 ± 3 nm. AFM tip scans of the polymer film induce either abrasive surface patterns or nanoscale ripples, which depend upon the tip force, temperature, and number of scans. The evolution of the lamellar patterns is explained by the polymer film molecular structure and mode I crack propagation in the polymer combined with the stick-and-slip behavior of the AFM tip. The HT-AFM measurements at various tip-sample temperatures and scanning speeds yield several thermophysical quantities: the PEO melting temperature of 54 ± 12 °C, the PS glass transition temperature of 54 ± 12 °C, the PS-b-PEO specific heat of 3.6 ± 2.7 J g(-1) K(-1), the PEO melting enthalpy of 111 ± 88 J g(-1), and the free energy of Helmholtz for PEO unfolding (and melting) of 10(-20) J nm(-2). These quantities are obtained for PS-b-PEO volumes of 30,000 nm(3), which correspond to 30 ag of the polymer.
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Affiliation(s)
- Reginald H Rice
- Department of Physics, Kansas State University, Manhattan, Kansas 66503, USA
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