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Jung W, Koirala GR, Lee JS, Kim JU, Park B, Jo YJ, Jeong C, Hong H, Kwon K, Ye YS, Kim J, Lee K, Kim TI. Solvent-Assisted Filling of Liquid Metal and Its Selective Dewetting for the Multilayered 3D Interconnect in Stretchable Electronics. ACS NANO 2022; 16:21471-21481. [PMID: 36453938 DOI: 10.1021/acsnano.2c09994] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
As stretchable electronics are rapidly developing and becoming complex, the requirement for stretchable, multilayered, and large-area printed circuit boards (PCBs) is emerging. This demands a stretchable electrode and its vertical interconnect access (via) for 3-dimensional (3D) connectivity between layers. Here, we demonstrate solvent-assisted liquid metal (LM) filling into the submicrometer channel (∼400 nm), including via-hole filling and selective dewetting of LM. We provide the theoretical background of solvent-assisted LM filling and selective dewetting and reveal the osmotic pressure arising from anomalous mass transport phenomena, case II diffusion, which drives negative pressure, the spontaneous pulling of LM into the open channel. Also, we suggest design criteria for the geometry and dimension of LM interconnects to obtain structural stability without dewetting, based on the theoretical and computational background. We demonstrate a simple stretchable near-field communication (NFC) device including transferred micrometer-size light-emitting diodes (LEDs) with only 230 μm to the stretchable liquid metal PCB, without any soldering process. The device operates stably under repetitive stretching and releasing (∼50% uniaxial strain) due to the stable connection through the LM via between the upper and lower layers. Finally, we propose a concept for modular-type stretchable electronics, based on the cohesive liquid nature of LM. As a building block, the functional module can be easily removed from a mainframe, and replaced by another functional module, to suit user demand.
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Affiliation(s)
- Woojin Jung
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Gyan Raj Koirala
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Ju Seung Lee
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Jong Uk Kim
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Byeonghak Park
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Young Jin Jo
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Chanho Jeong
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Haeleen Hong
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Kiyoon Kwon
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Yeong-Sinn Ye
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Jiwon Kim
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Kanghyuk Lee
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Tae-Il Kim
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
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2
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Mondal S. Impact of the process conditions on polymer pattern morphology during spin coating over topological surfaces. SOFT MATTER 2021; 17:1346-1358. [PMID: 33325977 DOI: 10.1039/d0sm01622e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Micro and nanofabrication techniques depend on the technology of polymer film casting. Spin coating is a relatively robust method to develop uniform polymer films over the substrate surface. However, polymer casting over a topographically prepatterned surface using the spin coating technique is challenging because of the complex transport phenomena involved in the process. Apart from the substrate wettability and the polymer composition, the geometry of the substrate prepatterns affects the polymer phase separation characteristics and thus the morphology of the polymer pattern. In this work the phase separation dynamics during the spinodal decomposition of a polymer-solvent system in a spin coating process is mathematically investigated. The effect of the prepattern topography, substrate wettability, spin-coating rotational speed, and polymer composition on the phase separation dynamics is investigated. The results reveal that the periodicity and phase difference of the polymer peaks with the topography are dependent on the geometric parameters and substrate wettability. The impact of the rotational motion, on the polymer film, is restricted by the surface roughness (due to the topological prepatterns). On reducing the polymer fraction in the solution, the transition from a uniform coating to film defects to isolated patches (wetting to dewetting) occurs. The surface wettability plays a crucial role in topology directed dewetting, which is not observed in flat substrates.
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Affiliation(s)
- Sourav Mondal
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
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3
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Tretyakov N, Papadopoulos P, Vollmer D, Butt HJ, Dünweg B, Daoulas KC. The Cassie-Wenzel transition of fluids on nanostructured substrates: Macroscopic force balance versus microscopic density-functional theory. J Chem Phys 2016; 145:134703. [DOI: 10.1063/1.4963792] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- Nikita Tretyakov
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Periklis Papadopoulos
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
- Physics Department, University of Ioannina, P.O. Box 1186, GR-45110 Ioannina, Greece
| | - Doris Vollmer
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Hans-Jürgen Butt
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Burkhard Dünweg
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
- Institut für Festkörperphysik, Technische Universität, Hochschulstraße 12, 64289 Darmstadt, Germany
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Kostas Ch. Daoulas
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
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4
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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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5
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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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6
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Haefner S, Benzaquen M, Bäumchen O, Salez T, Peters R, McGraw JD, Jacobs K, Raphaël E, Dalnoki-Veress K. Influence of slip on the Plateau-Rayleigh instability on a fibre. Nat Commun 2015; 6:7409. [PMID: 26068033 PMCID: PMC4490368 DOI: 10.1038/ncomms8409] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/05/2015] [Indexed: 11/29/2022] Open
Abstract
The Plateau-Rayleigh instability of a liquid column underlies a variety of fascinating phenomena that can be observed in everyday life. In contrast to the case of a free liquid cylinder, describing the evolution of a liquid layer on a solid fibre requires consideration of the solid-liquid interface. Here we revisit the Plateau-Rayleigh instability of a liquid coating a fibre by varying the hydrodynamic boundary condition at the fibre-liquid interface, from no slip to slip. Although the wavelength is not sensitive to the solid-liquid interface, we find that the growth rate of the undulations strongly depends on the hydrodynamic boundary condition. The experiments are in excellent agreement with a new thin-film theory incorporating slip, thus providing an original, quantitative and robust tool to measure slip lengths.
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Affiliation(s)
- Sabrina Haefner
- Department of Experimental Physics, Saarland University, D-66041 Saarbrücken, Germany
- Department of Physics and Astronomy, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4M1
| | - Michael Benzaquen
- PCT Lab, UMR CNRS 7083 Gulliver, ESPCI ParisTech, PSL Research University, 75005 Paris, France
| | - Oliver Bäumchen
- Department of Physics and Astronomy, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4M1
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany
| | - Thomas Salez
- PCT Lab, UMR CNRS 7083 Gulliver, ESPCI ParisTech, PSL Research University, 75005 Paris, France
| | - Robert Peters
- Department of Physics and Astronomy, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4M1
| | - Joshua D. McGraw
- Department of Experimental Physics, Saarland University, D-66041 Saarbrücken, Germany
| | - Karin Jacobs
- Department of Experimental Physics, Saarland University, D-66041 Saarbrücken, Germany
| | - Elie Raphaël
- PCT Lab, UMR CNRS 7083 Gulliver, ESPCI ParisTech, PSL Research University, 75005 Paris, France
| | - Kari Dalnoki-Veress
- Department of Physics and Astronomy, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4M1
- PCT Lab, UMR CNRS 7083 Gulliver, ESPCI ParisTech, PSL Research University, 75005 Paris, France
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7
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Zhang B, Chen J, Freyberg P, Reiter R, Mülhaupt R, Xu J, Reiter G. High-Temperature Stability of Dewetting-Induced Thin Polyethylene Filaments. Macromolecules 2015. [DOI: 10.1021/ma502345p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bin Zhang
- School of Materials Science & Engineering, Zhengzhou University, Zhengzhou 450002, China
| | - Jingbo Chen
- School of Materials Science & Engineering, Zhengzhou University, Zhengzhou 450002, China
| | | | | | | | - Jun Xu
- Institute of Polymer Science & Engineering, Tsinghua University, Beijing 100084, China
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Barman J, Swain D, Law BM, Seemann R, Herminghaus S, Khare K. Electrowetting actuated microfluidic transport in surface grooves with triangular cross section. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1231-1236. [PMID: 25531036 DOI: 10.1021/la504354a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Liquids show different static wetting morphologies in open triangular grooves depending upon the wedge angle (ψ) of the groove and the liquid contact angle (θ) with the substrate. Switching between different morphologies can be achieved either by varying the contact angle of the liquid or by changing the wedge angle of the groove. In the present work we manipulate the apparent contact angle of a liquid by electrowetting to switch between liquid morphologies, from droplet to filament, to achieve microfluidic transport of the liquid into open triangular grooves. The static length of liquid filaments in grooves is analyzed as a function of applied voltage for different applied ac frequencies. The dynamic advancement of the filament lengths in grooves is analyzed as a function of time for different applied voltages for two different liquids: first with contact angle greater than the wedge angle and second with contact angle smaller than the wedge angle. Later an exact electrical model is derived to explain the liquid transport in triangular grooves actuated by electrowetting which includes the precise geometry of the liquid morphology.
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Affiliation(s)
- Jitesh Barman
- Department of Physics and ‡Department of Mechanical Engineering, Indian Institute of Technology Kanpur , Kanpur 208016, India
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9
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Roy S, Biswas D, Salunke N, Das A, Vutukuri P, Singh R, Mukherjee R. Control of Morphology in Pattern Directed Dewetting of a Thin Polymer Bilayer. Macromolecules 2013. [DOI: 10.1021/ma3018525] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sudeshna Roy
- Department of Chemical
Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721
302, India
| | - Debarati Biswas
- Department of Chemical
Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721
302, India
| | - Namrata Salunke
- Department of Chemical
Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721
302, India
| | - Ajit Das
- Department of Chemical
Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721
302, India
| | - Pavanaphani Vutukuri
- Department of Chemical
Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721
302, India
| | - Ravdeep Singh
- Department of Chemical
Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721
302, India
| | - Rabibrata Mukherjee
- Department of Chemical
Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721
302, India
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10
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Roy S, Mukherjee R. Ordered to isotropic morphology transition in pattern-directed dewetting of polymer thin films on substrates with different feature heights. ACS APPLIED MATERIALS & INTERFACES 2012; 4:5375-85. [PMID: 22999159 DOI: 10.1021/am301311d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Controlled dewetting of a thin polymer film on a topographically patterned substrate is an interesting approach for aligning isotropic dewetted structures. In this article, we investigate the influence of substrate feature height (H(S)) on the dewetting pathway and final pattern morphology by studying the dewetting of polystyrene (PS) thin films on grating substrates with identical periodicity (λ(P) = 1.5 μm), but H(S) varying between 10 nm and 120 nm. We identify four distinct categories of final dewetted morphology, with different extent of ordering: (1) array of aligned droplets (H(S) ≈ 120 nm); (2) aligned undulating ribbons (H(S) ≈ 70-100 nm); (3) multilength scale structures with coexisting large droplets uncorrelated to the substrate and smaller droplets/ribbons aligned along the stripes (H(S) ≈ 40-60 nm); and (4) large droplets completely uncorrelated to the substrate (H(S) < 25 nm). The distinct morphologies across the categories are attributed to two major factors: (a) whether the as-cast film is continuous (H(S)≤ 80 nm) or discontinuous (H(S)≥ 100 nm) and (b) in case of a continuous film, whether the film ruptures along each substrate stripe (H(S)≥ 70 nm) or with nucleation of random holes that are not correlated to the substrate features (H(S)≤ 60 nm). While the ranges of H(S) values indicated in the parentheses are valid for PS films with an equivalent thickness (h(E)) ≈ 50.3 nm on a flat substrate, a change in h(E) merely alters the cut-off values of H(S), as the final dewetted morphologies and transition across categories remain generically unaltered. We finally show that the structures obtained by dewetting on different H(S) substrates exhibits different levels of hydrophobicity because of combined spatial variation of chemical and topographic contrast along the surface. Thus, the work reported in this article can find potential application in fabricating surfaces with controlled wettability.
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Affiliation(s)
- Sudeshna Roy
- Department of Chemical Engineering, Indian Institute of Technology-Kharagpur, West Bengal, 721 302, India
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11
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Roy S, Ansari KJ, Jampa SSK, Vutukuri P, Mukherjee R. Influence of substrate wettability on the morphology of thin polymer films spin-coated on topographically patterned substrates. ACS APPLIED MATERIALS & INTERFACES 2012; 4:1887-1896. [PMID: 22468781 DOI: 10.1021/am300201a] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We show that the morphology of a thin polymer film spin coated directly on to a topographically patterned substrate is strongly influenced by the wettability of the substrate, in addition to other well-known parameters such as concentration of the polymer solution (c(n)), spin speed (RPM), and spin duration. Similar to spin coating on a flat surface, (1, 2) on a topographically patterned substrate as well, a continuous film forms only above a critical polymer solution concentration (c(t)*), for a specific RPM and dispensed drop volume. It is believed that for c(n) > c(t)*, the resulting continuous film on a topographically patterned substrate has an undulating top surface, where the surface undulations are in phase with the underlying substrate patterns. (3) On the basis of experiments involving spin coating of polymer thin films on topographically patterned grating substrates, we show that the surface undulations on the film are in phase with the substrate patterns only when the substrate is completely wetted (CW) by the solvent. In contrast, when the substrate is partially wetted (PW) by the solvent, then the undulations are 180° out of phase with respect to the substrate patterns. We further show that for c(n) < c(t)*, a variety of ordered and disordered structures, like array of aligned droplets, isolated strips of polymers, etc., result on both CW and PW substrates, depending on c(n).
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Affiliation(s)
- Sudeshna Roy
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, West Bengal, India
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12
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Verma A, Sharma A. Sub-40 nm polymer dot arrays by self-organized dewetting of electron beam treated ultrathin polymer films. RSC Adv 2012. [DOI: 10.1039/c2ra00956k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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13
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Seemann R, Brinkmann M, Herminghaus S, Khare K, Law BM, McBride S, Kostourou K, Gurevich E, Bommer S, Herrmann C, Michler D. Wetting morphologies and their transitions in grooved substrates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:184108. [PMID: 21508471 DOI: 10.1088/0953-8984/23/18/184108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
When exposed to a partially wetting liquid, many natural and artificial surfaces equipped with complex topographies display a rich variety of liquid interfacial morphologies. In the present article, we focus on a few simple paradigmatic surface topographies and elaborate on the statics and dynamics of the resulting wetting morphologies. It is demonstrated that the spectrum of wetting morphologies increases with increasing complexity of the groove structure. On elastically deformable substrates, additional structures in the liquid morphologies can be observed, which are caused by deformations of the groove geometry in the presence of capillary forces. The emergence of certain liquid morphologies in grooves can be actively controlled by changes in wettability and geometry. For electrically conducting solid substrates, the apparent contact angle can be varied by electrowetting. This allows, depending on groove geometry, a reversible or irreversible transport of liquid along surface grooves. In the case of irreversible liquid transport in triangular grooves, the dynamics of the emerging instability is sensitive to the apparent hydrodynamic slip at the substrate. On elastic substrates, the geometry can be varied in a straightforward manner by stretching or relaxing the sample. The imbibition velocity in deformable grooves is significantly reduced compared to solid grooves, which is a result of the microscopic deformation of the elastic groove material close to the three phase contact line.
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Affiliation(s)
- Ralf Seemann
- Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany.
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14
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Patterning dewetting in thin polymer films by spatially directed photocrosslinking. J Colloid Interface Sci 2010; 351:556-60. [PMID: 20728089 DOI: 10.1016/j.jcis.2010.07.070] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 07/26/2010] [Accepted: 07/28/2010] [Indexed: 11/23/2022]
Abstract
In this report we examine the dewetting of spin-cast poly (styrene) films in a confined geometry. We designed a platform for laterally confining PS by photo-patterning crosslinks in spin-coated thin films. Heating the patterned film above the glass transition temperature of PS results in localized dewetting patterns in regions that were not crosslinked, while the crosslinked pattern serves as a rigid barrier that confines the retraction of the uncrosslinked polymer in micron-sized domains. The barriers also provide a favorable surface that the liquid PS wets onto, forming a rim at the boundary of crosslinked and uncrosslinked polymer. The resulting patterns are shown to be dependent on the irradiation and annealing time, the dimensions of the uncrosslinked region and the thickness of the film.
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