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Bhandaru N, Mukherjee R. Ordering in Dewetting of a Thin Polymer Bilayer with a Topographically Patterned Interface. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02559] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nandini Bhandaru
- Department of Chemical Engineering, BITS Pilani, Hyderabad, Telangana 500078, India
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
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Zhang Z, Ding J, Ocko BM, Fluerasu A, Wiegart L, Zhang Y, Kobrak M, Tian Y, Zhang H, Lhermitte J, Choi CH, Fisher FT, Yager KG, Black CT. Nanoscale viscosity of confined polyethylene oxide. Phys Rev E 2020; 100:062503. [PMID: 31962430 DOI: 10.1103/physreve.100.062503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Indexed: 11/07/2022]
Abstract
Complex fluids near interfaces or confined within nanoscale volumes can exhibit substantial shifts in physical properties compared to bulk, including glass transition temperature, phase separation, and crystallization. Because studies of these effects typically use thin film samples with one dimension of confinement, it is generally unclear how more extreme spatial confinement may influence these properties. In this work, we used x-ray photon correlation spectroscopy and gold nanoprobes to characterize polyethylene oxide confined by nanostructured gratings (<100nm width) and measured the viscosity in this nanoconfinement regime to be ∼500 times the bulk viscosity. This enhanced viscosity occurs even when the scale of confinement is several times the polymer's radius of gyration, consistent with previous reports of polymer viscosity near flat interfaces.
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Affiliation(s)
- Zheng Zhang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, USA
| | - Junjun Ding
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey, USA
| | - Benjamin M Ocko
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, USA
| | - Andrei Fluerasu
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, USA
| | - Lutz Wiegart
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, USA
| | - Yugang Zhang
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, USA
| | - Mark Kobrak
- Brooklyn College and the Graduate Center of the City University of New York, Brooklyn, New York, USA
| | - Ye Tian
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, USA
| | - Honghu Zhang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, USA
| | - Julien Lhermitte
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, USA
| | - Chang-Hwan Choi
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey, USA
| | - Frank T Fisher
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey, USA
| | - Kevin G Yager
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, USA
| | - Charles T Black
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, USA
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Kim I, Khang DY. Facile patterning and transfer printing of ferroelectric P (VDF-TrFE) microstructures by topographic dewetting and Rayleigh-Plateau instability. J Appl Polym Sci 2017. [DOI: 10.1002/app.45028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Inkyoung Kim
- Department of Materials Science and Engineering; Yonsei University; Seoul 03722 Korea
| | - Dahl-Young Khang
- Department of Materials Science and Engineering; Yonsei University; Seoul 03722 Korea
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Ok S, Sheets J, Welch S, Kaya S, Jalilov A, Cole DR. Tuning hydrophobicity of a fluorinated terpolymer in differently assembled thin films. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Salim Ok
- School of Earth Sciences; The Ohio State University; Columbus Ohio 43210
| | - Julia Sheets
- School of Earth Sciences; The Ohio State University; Columbus Ohio 43210
| | - Susan Welch
- School of Earth Sciences; The Ohio State University; Columbus Ohio 43210
| | - Savas Kaya
- School of Electrical Engineering and Computer Science; Ohio University; Athens Ohio 45701
| | - Almaz Jalilov
- Department of Chemistry; Rice University; 6100 Main Street Houston Texas 77005
| | - David R. Cole
- School of Earth Sciences; The Ohio State University; Columbus Ohio 43210
- Department of Chemistry; The Ohio State University; Columbus Ohio 43210
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Bhandaru N, Das A, Mukherjee R. Confinement induced ordering in dewetting of ultra-thin polymer bilayers on nanopatterned substrates. NANOSCALE 2016; 8:1073-1087. [PMID: 26658720 DOI: 10.1039/c5nr06690e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the dewetting of a thin bilayer of polystyrene (PS) and poly(methylmethacrylate) (PMMA) on a topographically patterned nonwettable substrate comprising an array of pillars, arranged in a square lattice. With a gradual increase in the concentration of the PMMA solution (Cn-PMMA), the morphology of the bottom layer changes to: (1) an aligned array of spin dewetted droplets arranged along substrate grooves at very low Cn-PMMA; (2) an interconnected network of threads surrounding each pillar at intermediate Cn-PMMA; and (3) a continuous bottom layer at higher Cn-PMMA. On the other hand the morphology of the PS top layer depends largely on the nature of the pre-existing bottom layer, in addition to Cn-PS. An ordered array of PMMA core-PS shell droplets forms right after spin coating when both Cn-PMMA and Cn-PS are very low. Bilayers with all other initial configurations evolve during thermal annealing, resulting in a variety of ordered structures. Unique morphologies realized include laterally coexisting structures of the two polymers confined within the substrate grooves due to initial rupture of the bottom layer on the substrate followed by a squeezing flow of the top layer; an array of core-shell and single polymer droplets arranged in an alternating order etc., to highlight a few. Such structures cannot be fabricated by any stand-alone lithography technique. On the other hand, in some cases the partially dewetted bottom layer imparts stability to an intact top PS layer against dewetting. Apart from ordering, under certain specific conditions significant miniaturization and downsizing of dewetted feature periodicity and dimension as compared to dewetting of a single layer on a flat substrate is observed. With the help of a morphology phase diagram we show that ordering is achieved over a wide combination of Cn-PMMA and Cn-PS, though the morphology and dewetting pathway differs significantly with variation in the thickness of the individual layers.
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Affiliation(s)
- Nandini Bhandaru
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, West Bengal, Pin 721302, India.
| | - Anuja Das
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, West Bengal, Pin 721302, India.
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, West Bengal, Pin 721302, India.
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Mukherjee R, Sharma A. Instability, self-organization and pattern formation in thin soft films. SOFT MATTER 2015; 11:8717-8740. [PMID: 26412507 DOI: 10.1039/c5sm01724f] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The free surface of a thin soft polymer film is often found to become unstable and self-organizes into various meso-scale structures. In this article we classify the instability of a thin polymer film into three broad categories, which are: category 1: instability of an ultra-thin (<100 nm) viscous film engendered by amplification of thermally excited surface capillary waves due to interfacial dispersive van der Waals forces; category 2: instability arising from the attractive inter-surface interactions between the free surface of a soft film exhibiting room temperature elasticity and another rigid surface in its contact proximity; and category 3: instability caused by an externally applied field such as an electric field or a thermal gradient, observed in both viscous and elastic films. We review the salient features of each instability class and highlight how characteristic length scales, feature morphologies, evolution pathways, etc. depend on initial properties such as film thickness, visco-elasticity (rheology), residual stress, and film preparation conditions. We emphasize various possible strategies for aligning and ordering of the otherwise isotropic structures by combining the essential concepts of bottom-up and top-down approaches. A perspective, including a possible future direction of research, novelty and limitations of the methods, particularly in comparison to the existing patterning techniques, is also presented for each setting.
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Affiliation(s)
- Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology, Kharagpur, 721 302, India.
| | - Ashutosh Sharma
- Department of Chemical Engineering and Nano-science Center, Indian Institute of Technology, Kanpur, 208016, India.
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Zhang Z, Hilton GC, Yang R, Ding Y. Capillary rupture of suspended polymer concentric rings. SOFT MATTER 2015; 11:7264-7269. [PMID: 26287952 DOI: 10.1039/c5sm01537e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present the first experimental study on the simultaneous capillary instability amongst viscous concentric rings suspended atop an immiscible medium. The rings ruptured upon annealing, with three types of phase correlation between neighboring rings. In the case of weak substrate confinement, the rings ruptured independently when they were sparsely distanced, but via an out-of-phase mode when packed closer. If the substrate confinement was strong, the rings would rupture via an in-phase mode, resulting in radially aligned droplets. The concentric ring geometry caused a competition between the phase correlation of neighboring rings and the kinetically favorable wavelength, yielding an intriguing, recursive surface pattern. This frustrated pattern formation behavior was accounted for by a scaling analysis.
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Affiliation(s)
- Zheng Zhang
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, USA.
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