1
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Petek ES, Katsumata R. Thickness Dependence of Contact Angles in Multilayered Ultrathin Polymer Films. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Evon S. Petek
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Dr, Amherst, Massachusetts 01003, United States
| | - Reika Katsumata
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Dr, Amherst, Massachusetts 01003, United States
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2
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Residual changes and thickness effects in glass-forming polymer thin films after solvent vapor annealing. POLYMER 2022. [DOI: 10.1016/j.polymer.2021.124417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Giermanska J, Ben Jabrallah S, Delorme N, Vignaud G, Chapel JP. Direct experimental evidences of the density variation of ultrathin polymer films with thickness. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123934] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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4
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Structural Evolution of Nanophase Separated Block Copolymer Patterns in Supercritical CO 2. NANOMATERIALS 2021; 11:nano11030669. [PMID: 33800510 PMCID: PMC7998665 DOI: 10.3390/nano11030669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 11/16/2022]
Abstract
Nanopatterns can readily be formed by annealing block copolymers (BCPs) in organic solvents at moderate or high temperatures. However, this approach can be challenging from an environmental and industrial point of view. Herein, we describe a simple and environmentally friendly alternative to achieve periodically ordered nanoscale phase separated BCP structures. Asymmetric polystyrene-b-poly(ethylene oxide) (PS-b-PEO) thin film patterns of different molecular weight were achieved by annealing in supercritical carbon dioxide (sc-CO2). Microphase separation of PS-b-PEO (16,000–5000) film patterns were achieved by annealing in scCO2 at a relatively low temperature was previously reported by our group. The effects of annealing temperature, time and depressurisation rates for the polymer system were also discussed. In this article, we have expanded this study to create new knowledge on the structural and dimensional evolution of nanohole and line/space surface periodicity of four other different molecular weights PS-b-PEO systems. Periodic, well defined, hexagonally ordered films of line and hole patterns were obtained at low CO2 temperatures (35–40 °C) and pressures (1200–1300 psi). Further, the changes in morphology, ordering and feature sizes for a new PS-b-PEO system (42,000–11,500) are discussed in detail upon changing the scCO2 annealing parameters (temperature, film thickness, depressurization rates, etc.). In relation to our previous reports, the broad annealing temperature and depressurisation rate were explored together for different film thicknesses. In addition, the effects of SCF annealing for three other BCP systems (PEO-b-PS, PS-b-PDMS, PS-b-PLA) is also investigated with similar processing conditions. The patterns were also generated on a graphoepitaxial substrate for device application.
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5
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Velez NR, Allen FI, Jones MA, Govindjee S, Meyers GF, Minor AM. Extreme Ductility in Freestanding Polystyrene Thin Films. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01387] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nathan R. Velez
- Department of Materials Science and Engineering, UC Berkeley, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular Foundry, LBNL, Berkeley, California 94720, United States
| | - Frances I. Allen
- Department of Materials Science and Engineering, UC Berkeley, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular Foundry, LBNL, Berkeley, California 94720, United States
| | - Mary Ann Jones
- Core R&D—Analytical Sciences, The Dow Chemical Company, Midland, Michigan 48667, United States
| | - Sanjay Govindjee
- Department of Civil and Environmental Engineering, UC Berkeley, Berkeley, California 94720, United States
| | - Gregory F. Meyers
- Core R&D—Analytical Sciences, The Dow Chemical Company, Midland, Michigan 48667, United States
| | - Andrew M. Minor
- Department of Materials Science and Engineering, UC Berkeley, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular Foundry, LBNL, Berkeley, California 94720, United States
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6
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Lomate GB, Dandi B, Mishra S. Development of antimicrobial LDPE/Cu nanocomposite food packaging film for extended shelf life of peda. Food Packag Shelf Life 2018. [DOI: 10.1016/j.fpsl.2018.04.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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7
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Giammaria TJ, Ferrarese Lupi F, Seguini G, Sparnacci K, Antonioli D, Gianotti V, Laus M, Perego M. Effect of Entrapped Solvent on the Evolution of Lateral Order in Self-Assembled P(S-r-MMA)/PS-b-PMMA Systems with Different Thicknesses. ACS APPLIED MATERIALS & INTERFACES 2017; 9:31215-31223. [PMID: 28195457 DOI: 10.1021/acsami.6b14332] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Block copolymers (BCPs) are emerging as a cost-effective nanofabrication tool to complement conventional optical lithography because they self-assemble in highly ordered polymeric templates with well-defined sub-20-nm periodic features. In this context, cylinder-forming polystyrene-block-poly(methyl methacrylate) BCPs are revealed as an interesting material of choice because the orientation of the nanostructures with respect to the underlying substrate can be effectively controlled by a poly(styrene-random-methyl methacrylate) random copolymer (RCP) brush layer grafted to the substrate prior to BCP deposition. In this work, we investigate the self-assembly process and lateral order evolution in RCP + BCP systems consisting of cylinder-forming PS-b-PMMA (67 kg mol-1, PS fraction of ∼70%) films with thicknesses of 30, 70, 100, and 130 nm deposited on RCP brush layers having thicknesses ranging from 2 to 20 nm. The self-assembly process is promoted by a rapid thermal processing machine operating at 250 °C for 300 s. The level of lateral order is determined by measuring the correlation length (ξ) in the self-assembled BCP films. Moreover, the amount of solvent (Φ) retained in the RCP + BCP systems is measured as a function of the thicknesses of the RCP and BCP layers, respectively. In the 30-nm-thick BCP films, an increase in Φ as a function of the thickness of the RCP brush layer significantly affects the self-assembly kinetics and the final extent of the lateral order in the BCP films. Conversely, no significant variations of ξ are observed in the 70-, 100-, and 130-nm-thick BCP films with increasing Φ.
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Affiliation(s)
- Tommaso Jacopo Giammaria
- Laboratorio MDM, IMM-CNR , Via C. Olivetti 2, 20864 Agrate Brianza, Italy
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte orientale ''A. Avogadro'' , Viale T. Michel 11, 15121 Alessandria, Italy
| | | | - Gabriele Seguini
- Laboratorio MDM, IMM-CNR , Via C. Olivetti 2, 20864 Agrate Brianza, Italy
| | - Katia Sparnacci
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte orientale ''A. Avogadro'' , Viale T. Michel 11, 15121 Alessandria, Italy
| | - Diego Antonioli
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte orientale ''A. Avogadro'' , Viale T. Michel 11, 15121 Alessandria, Italy
| | - Valentina Gianotti
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte orientale ''A. Avogadro'' , Viale T. Michel 11, 15121 Alessandria, Italy
| | - Michele Laus
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte orientale ''A. Avogadro'' , Viale T. Michel 11, 15121 Alessandria, Italy
| | - Michele Perego
- Laboratorio MDM, IMM-CNR , Via C. Olivetti 2, 20864 Agrate Brianza, Italy
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8
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Chebil MS, Vignaud G, Bal JK, Beuvier T, Delorme N, Grohens Y, Gibaud A. Reversibility in glass transition behavior after erasing stress induced by spin coating process. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.06.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Retamal MJ, Corrales TP, Cisternas MA, Moraga NH, Diaz DI, Catalan RE, Seifert B, Huber P, Volkmann UG. Surface Morphology of Vapor-Deposited Chitosan: Evidence of Solid-State Dewetting during the Formation of Biopolymer Films. Biomacromolecules 2016; 17:1142-9. [PMID: 26811988 DOI: 10.1021/acs.biomac.5b01750] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Chitosan is a useful and versatile biopolymer with several industrial and biological applications. Whereas its physical and physicochemical bulk properties have been explored quite intensively in the past, there is a lack of studies regarding the morphology and growth mechanisms of thin films of this biopolymer. Of particular interest for applications in bionanotechnology are ultrathin films with thicknesses under 500 Å. Here, we present a study of thin chitosan films prepared in a dry process using physical vapor deposition and in situ ellipsometric monitoring. The prepared films were analyzed with atomic force microscopy in order to correlate surface morphology with evaporation parameters. We find that the surface morphology of our final thin films depends on both the optical thickness, i.e., measured with ellipsometry, and the deposition rate. Our work shows that ultrathin biopolymer films can undergo dewetting during film formation, even in the absence of solvents and thermal annealing.
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Affiliation(s)
| | - Tomas P Corrales
- Instituto de Alta Investigacion, Universidad de Tarapaca , Casilla 7-D, 1000007 Arica, Chile
| | | | | | | | | | | | - Patrick Huber
- Institute of Materials Physics and Technology, Hamburg University of Technology (TUHH) , D-21073 Hamburg-Harburg, Germany
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10
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Getting to the bottom morphology of block copolymer thin films. CHINESE JOURNAL OF POLYMER SCIENCE 2015. [DOI: 10.1007/s10118-016-1731-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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11
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Buss F, Göcke J, Scharfer P, Schabel W. From Micro to Nano Thin Polymer Layers: Thickness and Concentration Dependence of Sorption and the Solvent Diffusion Coefficient. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01648] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Felix Buss
- Institute of Thermal Process
Engineering, Thin Film Technology, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Johannes Göcke
- Institute of Thermal Process
Engineering, Thin Film Technology, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Philip Scharfer
- Institute of Thermal Process
Engineering, Thin Film Technology, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Wilhelm Schabel
- Institute of Thermal Process
Engineering, Thin Film Technology, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
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12
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Bhattacharya S, Dey A, Chowdhury A. Probing Differential Hydration of Poly(vinylpyrrolidone) Thin Films Using Tracer Mobility: An Insight from Fluorescence Correlation Spectroscopy. J Phys Chem B 2014; 118:5240-9. [DOI: 10.1021/jp409563k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sukanya Bhattacharya
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Arghya Dey
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Arindam Chowdhury
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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13
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Ghoshal T, Senthamaraikannan R, Shaw MT, Holmes JD, Morris MA. Fabrication of ordered, large scale, horizontally-aligned si nanowire arrays based on an in situ hard mask block copolymer approach. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:1207-16. [PMID: 24277486 DOI: 10.1002/adma.201304096] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 09/17/2013] [Indexed: 05/25/2023]
Abstract
A simple technique is demonstrated to fabricate horizontal, uniform, and hexagonally arranged Sinanowire arrays with controlled orientation and density at spatially well defined locations on a substrate based on an in situ hard-mask pattern-formation approach by microphase-separated block-copolymer thin films. The technique may have significant application in the manufacture of transistor circuitry.
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Affiliation(s)
- Tandra Ghoshal
- Materials Research Group, Department of Chemistry and Tyndall National Institute, University College Cork, Cork, Ireland 2 Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland
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14
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Ferrarese Lupi F, Giammaria TJ, Ceresoli M, Seguini G, Sparnacci K, Antonioli D, Gianotti V, Laus M, Perego M. Rapid thermal processing of self-assembling block copolymer thin films. NANOTECHNOLOGY 2013; 24:315601. [PMID: 23851718 DOI: 10.1088/0957-4484/24/31/315601] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Self-assembling block copolymers generate nanostructured patterns which are useful for a wide range of applications. In this paper we demonstrate the capability to control the morphology of the self-assembling process of PS-b-PMMA diblock copolymer thin films on unpatterned surfaces by means of fast thermal treatment performed in a rapid thermal processing machine. The methodology involves the use of radiation sources in order to rapidly drive the polymeric film above the glass transition temperature. Highly ordered patterns were obtained for perpendicular-oriented cylindrical and lamellar PS-b-PMMA block copolymers in less than 60 s. This approach offers the unprecedented opportunity to investigate in detail the kinetics of the block copolymer self-assembly during the early stages of the process, providing a much deeper understanding of the chemical and physical phenomena governing these processes.
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Affiliation(s)
- F Ferrarese Lupi
- Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, Agrate Brianza (MB), Italy
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15
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Hoppe ET, Hopp I, Port M, Menges B, Papadakis CM. Optical properties of polybutadiene in the bulk and near a gold interface. Colloid Polym Sci 2012. [DOI: 10.1007/s00396-012-2711-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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16
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O’Driscoll BMD, Griffiths GH, Matsen MW, Hamley IW. Structure Variation and Evolution in Microphase-Separated Grafted Diblock Copolymer Films. Macromolecules 2011. [DOI: 10.1021/ma2010074] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Guy H. Griffiths
- Department of Mathematics, University of Reading, Whiteknights, Reading RG6 6AX, U.K
| | - Mark W. Matsen
- Department of Mathematics, University of Reading, Whiteknights, Reading RG6 6AX, U.K
| | - Ian W. Hamley
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K
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17
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Inoue R, Kawashima K, Matsui K, Nakamura M, Nishida K, Kanaya T, Yamada NL. Interfacial properties of polystyrene thin films as revealed by neutron reflectivity. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:031802. [PMID: 22060395 DOI: 10.1103/physreve.84.031802] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Indexed: 05/31/2023]
Abstract
We have studied the glass transition temperature (T(g)) and molecular mobility of polystyrene (PS) thin films near the interface between the polymer thin film and substrate with bilayer thin films consisting of surface hydrogenated PS (h-PS) and bottom deuterated PS (d-PS) using neutron reflectivity. With decreasing the thickness of the bottom d-PS layer, T(g) near the interface between the polymer thin film and substrate increased compared to bulk T(g) and a drastic increase of T(g) was observed for the bottom d-PS layer <155 Å thick. The orientation of polymer chains at the interface is supposed to be related to the increase of T(g) near the interface between the polymer and substrate. The polymer chain mobility decreased with thickness even for the bottom d-PS layer with no discernible change of T(g). It is considered that the numerous contacts between polymer chains and substrate are related to the decrease of mobility near the interface between the polymer thin film and substrate.
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Affiliation(s)
- Rintaro Inoue
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011, Japan.
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18
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Inoue R, Kawashima K, Matsui K, Kanaya T, Nishida K, Matsuba G, Hino M. Distributions of glass-transition temperature and thermal expansivity in multilayered polystyrene thin films studied by neutron reflectivity. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:021801. [PMID: 21405853 DOI: 10.1103/physreve.83.021801] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Indexed: 05/26/2023]
Abstract
We performed neutron reflectivity measurements on multilayered polymer thin films consisting of alternatively stacked deuterated polystyrene (d-PS) and hydrogenated polystyrene (h-PS) layers ∼200 Å thick as a function of temperature covering the glass-transition temperature T(g), and we found a wide distribution of T(g) as well as a distribution of the thermal expansivity α within the thin films, implying the dynamic heterogeneity of the thin films along the depth direction. The reported anomalous film thickness dependences of T(g) and α were reasonably understood in terms of the distributions, showing that the surface mobile layer and the bottom hard interfacial layer are, respectively, responsible for the depressions of T(g) and α with decreasing film thickness. The molecular mobility in each layer is also discussed in relation to the distribution of T(g), based on the results on mutual diffusion at the layer interface.
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Affiliation(s)
- Rintaro Inoue
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011, Japan
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19
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O’Driscoll BMD, Griffiths GH, Matsen MW, Perrier S, Ladmiral V, Hamley IW. Lateral Phase Separation in Grafted Diblock Copolymer Films. Macromolecules 2010. [DOI: 10.1021/ma101093f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Guy H. Griffiths
- Department of Mathematics, University of Reading, Whiteknights, Reading, RG6 6AX, U.K
| | - Mark W. Matsen
- Department of Mathematics, University of Reading, Whiteknights, Reading, RG6 6AX, U.K
| | - Sébastien Perrier
- Key Centre for Polymers and Colloids, School of Chemistry, University of Sydney, NSW, 2006, Australia
| | - Vincent Ladmiral
- Key Centre for Polymers and Colloids, School of Chemistry, University of Sydney, NSW, 2006, Australia
| | - Ian W. Hamley
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, U.K
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20
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Solomun T, Mix R, Sturm H. Immobilization of silanized DNA on glass: influence of the silane tether on the DNA hybridization. ACS APPLIED MATERIALS & INTERFACES 2010; 2:2171-2174. [PMID: 20735089 DOI: 10.1021/am100263t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Two trifunctional (trimethoxy and triethoxy) and one difunctional (methyldimethoxy) 3-mercaptopropyl-alkoxysilanes were covalently tethered to thiolated DNA oligonucleotides in solution. After deposition as microarrays onto glass, the immobilized DNA probes were tested for hybridization ability by a florescence-based method. The results demonstrate a large enhancement in the fluorescence signal when the functionality of the silane tether is reduced from three to two. An XPS analyses revealed that this is not due to a higher DNA surface density. FTIR spectra of the spin-coated silanes showed that the trifunctional silanes form branched and cyclic siloxane moieties, whereas the difunctional silane generates predominantly short straight siloxane chains. Therefore, the propensity of trifunctional silanes to form more complex networks leads to conformations of the bound DNA which are less favorable for the specific interaction with the complementary strand. The data implicate that further significant improvements in the DNA hybridization ability are possible by adroit choice of the silane system.
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21
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Zhang X, Yager KG, Kang S, Fredin NJ, Akgun B, Satija S, Douglas JF, Karim A, Jones RL. Solvent Retention in Thin Spin-Coated Polystyrene and Poly(methyl methacrylate) Homopolymer Films Studied By Neutron Reflectometry. Macromolecules 2009. [DOI: 10.1021/ma902168w] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | - Bulent Akgun
- NIST Center for Neutron Research
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742
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22
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Fitzgerald TG, Farrell RA, Petkov N, Bolger CT, Shaw MT, Charpin JPF, Gleeson JP, Holmes JD, Morris MA. Study on the combined effects of solvent evaporation and polymer flow upon block copolymer self-assembly and alignment on topographic patterns. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:13551-13560. [PMID: 19860380 DOI: 10.1021/la9018162] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Microphase separation of a polystyrene-block-polyisoprene-block-polystyrene triblock copolymer thin film under confined conditions (i.e., graphoepitaxy) results in ordered periodic arrays of polystyrene cylinders aligned parallel to the channel side-wall and base in a polyisoprene matrix. Polymer orientation and translational ordering with respect to the topographic substrate were elucidated by atomic force microscopy (AFM) while film thickness and polymer profile within the channel were monitored by cross-sectional transmission electron microscopy (TEM) as a function of time over a 6 h annealing period at 120 degrees C. Upon thermal annealing, the polymer film simultaneously undergoes three processes: microphase separation, evaporation of trapped solvent, and mass transport of polymer from the mesas into the channels. A significant volume of solvent is trapped within the polymer film upon spin coating arising from the increased polymer/substrate interfacial area due to the topographic pattern. Mass transport of polymer during this process results in nonuniform films, where subtle changes in the film thickness within the channel have profound effects on the microphase separation process. The initially disordered structure within the film underwent an orientation transition via an intermediate formation of perpendicular cylinders (nonequilibrium) to a parallel (equilibrium) orientation with respect to the channel base. Herein, we present a time-resolved study of the cylinder reorientation process detailing how changing film thickness during the annealing process dramatically affects both the local and lateral orientation of the observed structure. Finally, a brief mathematical model is provided to evaluate spin coating over a complex topography following a classical asymptotic approximation of the Navier-Stokes equations for the as-deposited films.
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Affiliation(s)
- Thomas G Fitzgerald
- Materials Chemistry Section, Chemistry Department, University College Cork, Cork, Ireland
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23
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Dietzel M, Troian SM. Formation of nanopillar arrays in ultrathin viscous films: the critical role of thermocapillary stresses. PHYSICAL REVIEW LETTERS 2009; 103:074501. [PMID: 19792647 DOI: 10.1103/physrevlett.103.074501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Indexed: 05/28/2023]
Abstract
Experiments by several groups during the past decade have shown that a molten polymer nanofilm subject to a large transverse thermal gradient undergoes spontaneous formation of periodic nanopillar arrays. The prevailing explanation is that coherent reflections of acoustic phonons within the film cause a periodic modulation of the radiation pressure which enhances pillar growth. By exploring a deformational instability of particular relevance to nanofilms, we demonstrate that thermocapillary forces play a crucial role in the formation process. Analytic and numerical predictions show good agreement with the pillar spacings obtained in experiment. Simulations of the interface equation further determine the rate of pillar growth of importance to technological applications.
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Affiliation(s)
- Mathias Dietzel
- California Institute of Technology, 1200 East California Boulevard, MC 128-95, Pasadena, California 91125, USA
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24
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Chung JY, Chastek TQ, Fasolka MJ, Ro HW, Stafford CM. Quantifying residual stress in nanoscale thin polymer films via surface wrinkling. ACS NANO 2009; 3:844-852. [PMID: 19298053 DOI: 10.1021/nn800853y] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Residual stress, a pervasive consequence of solid materials processing, is stress that remains in a material after external forces have been removed. In polymeric materials, residual stress results from processes, such as film formation, that force and then trap polymer chains into nonequilibrium stressed conformations. In solvent-cast films, which are central to a wide range of technologies, residual stress can cause detrimental effects, including microscopic defect formation and macroscopic dimensional changes. Since residual stress is difficult to measure accurately, particularly in nanoscale thin polymer films, it remains a challenge to understand and control. We present here a quantitative method of assessing residual stress in polymer thin films by monitoring the onset of strain-induced wrinkling instabilities. Using this approach, we show that thin (>100 nm) polystyrene films prepared via spin-coating possess residual stresses of approximately 30 MPa, close to the crazing and yield stress. In contrast to conventional stress measurement techniques such as wafer curvature, our technique has the resolution to measure residual stress in films as thin as 25 nm. Furthermore, we measure the dissipation of residual stress through two relaxation mechanisms: thermal annealing and plasticizer addition. In quantifying the amount of residual stress in these films, we find that the residual stress gradually decreases with increasing annealing time and plasticizer amounts. Our robust and simple route to measure residual stress adds a key component to the understanding of polymer thin film behavior and will enable identification of more effective processing routes that mitigate the detrimental effects of residual stress.
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Affiliation(s)
- Jun Young Chung
- Polymers Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
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Perlich J, Metwalli E, Schulz L, Georgii R, Müller-Buschbaum P. Solvent Content in Thin Spin-Coated Polystyrene Homopolymer Films. Macromolecules 2008. [DOI: 10.1021/ma801878j] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- J. Perlich
- Physik-Department E13, Technische Universität München, James-Franck-Str. 1, 85747 Garching, Germany, Département de Physique, Université Fribourg, Chemin Du Musée 3, 1700 Fribourg, Switzerland, and Forschungsneutronenquelle Heinz Maier-Leibnitz, Technische Universität München, Lichtenbergstr. 1, 85747 Garching, Germany
| | - E. Metwalli
- Physik-Department E13, Technische Universität München, James-Franck-Str. 1, 85747 Garching, Germany, Département de Physique, Université Fribourg, Chemin Du Musée 3, 1700 Fribourg, Switzerland, and Forschungsneutronenquelle Heinz Maier-Leibnitz, Technische Universität München, Lichtenbergstr. 1, 85747 Garching, Germany
| | - L. Schulz
- Physik-Department E13, Technische Universität München, James-Franck-Str. 1, 85747 Garching, Germany, Département de Physique, Université Fribourg, Chemin Du Musée 3, 1700 Fribourg, Switzerland, and Forschungsneutronenquelle Heinz Maier-Leibnitz, Technische Universität München, Lichtenbergstr. 1, 85747 Garching, Germany
| | - R. Georgii
- Physik-Department E13, Technische Universität München, James-Franck-Str. 1, 85747 Garching, Germany, Département de Physique, Université Fribourg, Chemin Du Musée 3, 1700 Fribourg, Switzerland, and Forschungsneutronenquelle Heinz Maier-Leibnitz, Technische Universität München, Lichtenbergstr. 1, 85747 Garching, Germany
| | - P. Müller-Buschbaum
- Physik-Department E13, Technische Universität München, James-Franck-Str. 1, 85747 Garching, Germany, Département de Physique, Université Fribourg, Chemin Du Musée 3, 1700 Fribourg, Switzerland, and Forschungsneutronenquelle Heinz Maier-Leibnitz, Technische Universität München, Lichtenbergstr. 1, 85747 Garching, Germany
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Zhang X, Berry BC, Yager KG, Kim S, Jones RL, Satija S, Pickel DL, Douglas JF, Karim A. Surface morphology diagram for cylinder-forming block copolymer thin films. ACS NANO 2008; 2:2331-2341. [PMID: 19206400 DOI: 10.1021/nn800643x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We investigate the effect of the ordering temperature (T) and film thickness (h(f)) on the surface morphology of flow-coated block copolymer (BCP) films of asymmetric poly(styrene-block-methyl methacrylate). Morphology transitions observed on the ordered film surface by atomic force microscopy (AFM) are associated with a perpendicular to a parallel cylinder BCP microphase orientation transition with respect to the substrate with increasing h(f). "Hybrid" surface patterns for intermediate h(f) between these limiting morphologies are correspondingly interpreted by a coexistence of these two BCP microphase orientations so that two "transitional" h(f) exist for each T. This explanation of our surface patterns is supported by both neutron reflectivity and rotational SANS measurements. The transitional h(f) values as a function of T define upper and lower surface morphology transition lines, h(fu) (T) and h(fl) (T), respectively, and a surface morphology diagram that should be useful in materials fabrication. Surprisingly, the BCP film surface morphology depends on the method of film formation (flow-coated versus spun-cast films) so that nonequilibrium effects are evidently operative. This morphological variability is attributed primarily to the trapping of residual solvent (toluene) within the film (quantified by neutron reflectivity) due to film vitrification while drying. This effect has significant implications for controlling film structure in nanomanufacturing applications based on BCP templates.
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Affiliation(s)
- Xiaohua Zhang
- Polymers Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
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Wang W, Vaughn MW. Morphology and amine accessibility of (3-aminopropyl) triethoxysilane films on glass surfaces. SCANNING 2008; 30:65-77. [PMID: 18320600 DOI: 10.1002/sca.20097] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
3-Aminopropyl) triethoxysilane (APTES) is commonly used to functionalize glass substrates because it can form an amine-reactive film that is tightly attached to the surface. In this study, we investigated the morphology and chemical reactivity of APTES films prepared on glass substrates using common deposition techniques. Films were prepared using concentrated vapor-phase deposition, dilute vapor-phase deposition, anhydrous organic-phase deposition and aqueous-phase deposition. All films were annealed, or cured, at 150 degrees C. The morphology of the films was quantified by fluorescence and by atomic force microscopy (AFM). The optical equivalent of the AFM images was computed and then used to directly compare optical and AFM images. Reactive amine density was determined by a picric acid assay and by a method that employed N-succinimidyl 3-[2-pyridyldithio]-propionamido (SPDP) cross-linked rhodamine. Fluorescence and AFM images showed that silane films prepared from dilute vapor-phase and aqueous-phase deposition were more uniform and had fewer domains than those deposited by the other methods. The ratio of picric acid-accessible amino groups to SPDP cross-linked rhodamine-accessible groups varied with the preparation method, suggesting reactant size-dependent difference in amine accessibility. We found a larger number of accessible amino groups on films prepared by vapor-phase deposition than on those prepared from solution deposition. The dilute vapor-phase deposition technique produced relatively few domains, and it should be a good choice for bioconjugation applications. There were appreciable differences in the films produced by each method. We suggest that these differences originate from differences in film rearrangement during annealing.
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Affiliation(s)
- Wei Wang
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409-4121, USA
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