1
|
Rahman MR, Shen L, Ewen JP, Collard B, Heyes DM, Dini D, Smith ER. Non-equilibrium molecular simulations of thin film rupture. J Chem Phys 2023; 158:2882242. [PMID: 37093990 DOI: 10.1063/5.0149974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 03/30/2023] [Indexed: 04/26/2023] Open
Abstract
The retraction of thin films, as described by the Taylor-Culick (TC) theory, is subject to widespread debate, particularly for films at the nanoscale. We use non-equilibrium molecular dynamics simulations to explore the validity of the assumptions used in continuum models by tracking the evolution of holes in a film. By deriving a new mathematical form for the surface shape and considering a locally varying surface tension at the front of the retracting film, we reconcile the original theory with our simulation to recover a corrected TC speed valid at the nanoscale.
Collapse
Affiliation(s)
- Muhammad Rizwanur Rahman
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Li Shen
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - James P Ewen
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Benjamin Collard
- Department of Materials Science, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - D M Heyes
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - E R Smith
- Department of Mechanical and Aerospace Engineering, Brunel University London, Uxbridge UB8 3PH, United Kingdom
| |
Collapse
|
2
|
Dewetting Kinetics of Thin Polymer Films with Different Architectures: Effect of Polymer Adsorption. CHINESE JOURNAL OF POLYMER SCIENCE 2018. [DOI: 10.1007/s10118-018-2111-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
3
|
Zhu Y, Yang Q, You J, Li Y. Composition fluctuation intensity effect on the stability of polymer films. RSC Adv 2016. [DOI: 10.1039/c6ra12723a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The composition fluctuation intensity dependence of the stability of a polymer film with a tiny amount of miscible component.
Collapse
Affiliation(s)
- Yu Zhu
- College of Material, Chemistry and Chemical Engineering
- Hangzhou Normal University
- Hangzhou 310036
- P. R. China
| | - Qiucheng Yang
- College of Material, Chemistry and Chemical Engineering
- Hangzhou Normal University
- Hangzhou 310036
- P. R. China
| | - Jichun You
- College of Material, Chemistry and Chemical Engineering
- Hangzhou Normal University
- Hangzhou 310036
- P. R. China
| | - Yongjin Li
- College of Material, Chemistry and Chemical Engineering
- Hangzhou Normal University
- Hangzhou 310036
- P. R. China
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
Cheng G, Perahia D. Dewetting and microphase separation in symmetric polystyrene‐
block
‐polyisoprene diblock copolymer ultrathin films. POLYM INT 2015. [DOI: 10.1002/pi.5022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Gang Cheng
- College of Life Science and Technology Beijing University of Chemical Technology Beijing 100029 China
- Materials Science and Engineering Program and Chemistry Department Clemson University SC 29634 USA
| | - Dvora Perahia
- Materials Science and Engineering Program and Chemistry Department Clemson University SC 29634 USA
| |
Collapse
|
6
|
|
7
|
Buraud JL, Noël O, Ausserré D. From permeation to pore nucleation in smectic stacks. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:8944-8949. [PMID: 23767927 DOI: 10.1021/la4003498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The last stage of the spreading of a stratified droplet in the odd wetting case is the evolution from a trilayer to a monolayer, that is, vanishing of the last bilayer in the stack. We studied it in the case of 8CB smectic liquid crystal on a hydrophilic surface. Receding of the last bilayer is accompanied by formation of pores in it, which appear in the outer part of it. From analysis of real-time experimental observations of this phenomenon, we demonstrate that the dislocation loops which border these pores are not located at the same height in the trilayer stack as the dislocation lines that border the bilayer. Also, careful analysis of our results using a recently developed theoretical approach of smectic liquid nanodrop spreading strongly suggests that pore nucleation is triggered by differences in chemical potential between adjacent layers, which contrasts with the classical scheme where it is attributed to lateral tension along the layers.
Collapse
Affiliation(s)
- Jean-Luc Buraud
- Molecular Landscapes, Biophotonic Horizons Group, CNRS-UMR 6087, Université du Maine, Le Mans, Sarthe 72000, France
| | | | | |
Collapse
|
8
|
Temperature-driven surface morphology evolution of poly(3-hydroxybutyrate) single layer and poly(3-hydroxybutyrate)/poly(vinyl phenol) bilayer on Si wafers. CHINESE JOURNAL OF POLYMER SCIENCE 2013. [DOI: 10.1007/s10118-013-1240-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
9
|
Probing Properties of Polymers in Thin Films Via Dewetting. GLASS TRANSITION, DYNAMICS AND HETEROGENEITY OF POLYMER THIN FILMS 2012. [DOI: 10.1007/12_2012_174] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
|
10
|
Wang S, Dössel L, Mavrinskiy A, Gao P, Feng X, Pisula W, Müllen K. Self-assembly and microstructural control of a hexa-peri-hexabenzocoronene-perylene diimide dyad by solvent vapor diffusion. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:2841-2846. [PMID: 21898792 DOI: 10.1002/smll.201100730] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/24/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Suhao Wang
- Max Planck Institute for Polymer Research, Mainz, Germany
| | | | | | | | | | | | | |
Collapse
|
11
|
Rathfon JM, Cohn RW, Crosby AJ, Rothstein JP, Tew GN. Confinement Effects on Chain Entanglement in Free-Standing Polystyrene Ultrathin Films. Macromolecules 2011. [DOI: 10.1021/ma1026324] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeremy M. Rathfon
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
- ElectroOptics Research Institute and Nanotechnology Center, University of Louisville, Louisville, Kentucky 40292, United States
| | - Robert W. Cohn
- ElectroOptics Research Institute and Nanotechnology Center, University of Louisville, Louisville, Kentucky 40292, United States
| | - Alfred J. Crosby
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Jonathan P. Rothstein
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Gregory N. Tew
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| |
Collapse
|
12
|
Verma A, Sharma A. Submicrometer Pattern Fabrication by Intensification of Instability in Ultrathin Polymer Films under a Water–Solvent Mix. Macromolecules 2011. [DOI: 10.1021/ma200113w] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ankur Verma
- Department of Chemical Engineering and DST Unit on Nanosciences, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Ashutosh Sharma
- Department of Chemical Engineering and DST Unit on Nanosciences, Indian Institute of Technology Kanpur, Kanpur 208016, India
| |
Collapse
|
13
|
|
14
|
Patra A, Bandyopadhyay D, Tomar G, Sharma A, Biswas G. Instability and dewetting of ultrathin solid viscoelastic films on homogeneous and heterogeneous substrates. J Chem Phys 2011; 134:064705. [DOI: 10.1063/1.3554748] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
15
|
Ma X, Crombez R, Ashaduzzaman M, Kunitake M, Slater L, Mourey T, Texter J. Polymer dewetting via stimuli responsive structural relaxation—contact angle analysis. Chem Commun (Camb) 2011; 47:10356-8. [DOI: 10.1039/c1cc12656c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
16
|
Rathfon JM, Cohn RW, Crosby AJ, Tew GN. Hole Nucleation and Growth in Free-Standing Polystyrene Ultrathin Films. Macromolecules 2010. [DOI: 10.1021/ma1020227] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jeremy M. Rathfon
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
- ElectroOptics Research Institute and Nanotechnology Center, University of Louisville, Louisville, Kentucky 40292, United States
| | - Robert W. Cohn
- ElectroOptics Research Institute and Nanotechnology Center, University of Louisville, Louisville, Kentucky 40292, United States
| | - Alfred J. Crosby
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Gregory N. Tew
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| |
Collapse
|
17
|
Mukherjee R, Das S, Das A, Sharma SK, Raychaudhuri AK, Sharma A. Stability and dewetting of metal nanoparticle filled thin polymer films: control of instability length scale and dynamics. ACS NANO 2010; 4:3709-3724. [PMID: 20560592 DOI: 10.1021/nn901912d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We investigate the influence of gold nanoparticle addition on the stability, dewetting, and pattern formation in ultrathin polymer-nanoparticle (NP) composite films by examining the length and time scales of instability, morphology, and dynamics of dewetting. For these 10-50 nm thick (h) polystyrene (PS) thin films containing uncapped gold nanoparticles (diameter approximately 3-4 nm), transitions from complete dewetting to arrested dewetting to absolute stability were observed depending on the concentration of the particles. Experiments show the existence of three distinct stability regimes: regime 1, complete dewetting leading to droplet formation for nanoparticle concentration of 2% (w/w) or below; regime 2, partial dewetting leading to formation of arrested holes for NP concentrations in the range of 3-6%; and regime 3, complete inhibition of dewetting for NP concentrations of 7% and above. Major results are (a) length scale of instability, where lambdaH approximately hn remains unchanged with NP concentration in regime 1 (n approximately 2) but increases in regime 2 with a change in the scaling relation (n approximately 3-3.5); (b) dynamics of instability and dewetting becomes progressively sluggish with an increase in the NP concentration; (c) there are distinct regimes of dewetting velocity at low NP concentrations; (d) force modulation AFM, as well as micro-Raman analysis, shows phase separation and aggregation of the gold nanoparticles within each dewetted polymer droplet leading to the formation of a metal core-polymer shell morphology. The polymer shell could be removed by washing in a selective solvent, thus exposing an array of bare gold nanoparticle aggregates.
Collapse
Affiliation(s)
- Rabibrata Mukherjee
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Pin 721 302, West Bengal, India
| | | | | | | | | | | |
Collapse
|
18
|
Bäumchen O, Jacobs K. Slip effects in polymer thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:033102. [PMID: 21386275 DOI: 10.1088/0953-8984/22/3/033102] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Probing the fluid dynamics of thin films is an excellent tool for studying the solid/liquid boundary condition. There is no need for external stimulation or pumping of the liquid, due to the fact that the dewetting process, an internal mechanism, acts as a driving force for liquid flow. Viscous dissipation, within the liquid, and slippage balance interfacial forces. Thus, friction at the solid/liquid interface plays a key role towards the flow dynamics of the liquid. Probing the temporal and spatial evolution of growing holes or retracting straight fronts gives, in combination with theoretical models, information on the liquid flow field and, especially, the boundary condition at the interface. We review the basic models and experimental results obtained during the last several years with exclusive regard to polymers as ideal model liquids for fluid flow. Moreover, concepts that aim to explain slippage on the molecular scale are summarized and discussed.
Collapse
Affiliation(s)
- O Bäumchen
- Department of Experimental Physics, Saarland University, D-66041 Saarbrücken, Germany
| | | |
Collapse
|
19
|
Xue L, Han Y. Autophobic dewetting of a poly(methyl methacrylate) thin film on a silicon wafer treated in good solvent vapor. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:5135-5140. [PMID: 19278204 DOI: 10.1021/la8041814] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The wettability of thin poly(methyl methacrylate) (PMMA) films on a silicon wafer with a native oxide layer exposed to solvent vapors is dependent on the solvent properties. In the nonsolvent vapor, the film spread on the substrate with some protrusions generated on the film surface. In the good solvent vapor, dewetting happened. A new interface formed between the anchored PMMA chains and the swollen upper part of the film. Entropy effects caused the upper movable chains to dewet on the anchored chains. The rim instability depended on the surface tension of solvent (i.e., the finger was generated in acetone vapor (gamma(acetone) = 24 mN/m), not in dioxane vapor (gamma(dioxane) = 33 mN/m)). The spacing (lambda) that grew as an exponential function of film thickness h scaled as approximately h(1.31), whereas the mean size (D) of the resulting droplets grew linearly with h.
Collapse
Affiliation(s)
- Longjian Xue
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, PR China
| | | |
Collapse
|
20
|
Ziebert F, Raphaël E. Dewetting dynamics of stressed viscoelastic thin polymer films. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:031605. [PMID: 19391952 DOI: 10.1103/physreve.79.031605] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Indexed: 05/27/2023]
Abstract
Ultrathin polymer films that are produced, e.g., by spin coating are believed to be stressed since polymers are "frozen in" into out-of-equilibrium configurations during this process. In the framework of a viscoelastic thin-film model, we study the effects of lateral residual stresses on the dewetting dynamics of the film. The temporal evolution of the height profiles and the velocity profiles inside the film as well as the dissipation mechanisms are investigated in detail. Both the shape of the profiles and the importance of frictional dissipation vs viscous dissipation inside the film are found to change in the course of dewetting. The interplay of the nonstationary profiles, the relaxing initial stress, and the changes in the dominance of the two dissipation mechanisms caused by nonlinear friction with the substrate is responsible for the rich behavior of the system. In particular, our analysis sheds a different light on the occurrence of the unexpected maximum in the rim width obtained recently in experiments on polystyrene-polydimethylsiloxane systems.
Collapse
Affiliation(s)
- Falko Ziebert
- Laboratoire de Physico-Chimie Théorique-UMR CNRS Gulliver 7083, ESPCI, 10 rue Vauquelin, F-75231 Paris, France
| | | |
Collapse
|
21
|
Xu L, Shi T, An L. The dewetting dynamics of the polymer thin film by solvent annealing. J Chem Phys 2008; 129:044904. [DOI: 10.1063/1.2918734] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
22
|
Al Akhrass S, Reiter G, Hou SY, Yang MH, Chang YL, Chang FC, Wang CF, Yang ACM. Viscoelastic thin polymer films under transient residual stresses: two-stage dewetting on soft substrates. PHYSICAL REVIEW LETTERS 2008; 100:178301. [PMID: 18518343 DOI: 10.1103/physrevlett.100.178301] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Indexed: 05/26/2023]
Abstract
A nonmonotonic, two-stage dewetting behavior was observed for spin coated thin viscoelastic polymer films on soft elastic substrates. At times shorter than the relaxation time of the polymer (t<tau_{rep}), dewetting generated deep trenches in the soft rubbery substrate which, in turn, almost stopped dewetting. At later stages (t>>tau_{rep}), dewetting accelerated, accompanied by an unstable rim. However, holes nucleated at t<tau_{rep} showed only this second-stage behavior. Our observations are attributed to large elastic deformations in the substrate caused by transient residual stresses within the film.
Collapse
Affiliation(s)
- S Al Akhrass
- Institute de Chimie des Surfaces et Interfaces, UHA-CNRS, 15, rue J. Starcky, 68057 Mulhouse Cedex, France
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Fetzer R, Jacobs K. Slippage of Newtonian liquids: influence on the dynamics of dewetting thin films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:11617-11622. [PMID: 17918979 DOI: 10.1021/la701746r] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Slippage of Newtonian liquids in the presence of a solid substrate is a newly found phenomenon, the origin of which is still under debate. In this article, we present a new analysis method to extract the slip length. Enhancing the slip of liquids is an important issue for microfluidic devices that demand for high throughput at low pumping power. We study the velocity of short-chained liquid polystyrene (PS) films dewetting from nonwettable solid substrates. We show how the dynamics of dewetting is influenced by slippage, and we compare the results of two types of substrates that give rise to different slip lengths. As substrates, Si wafers that have been coated with octadecyltrichlorosilane (OTS) or dodecyltrichlorosilane (DTS) were used. Our results demonstrate that the dewetting velocity for PS films on DTS is significantly larger than on OTS and that this difference originates from the different slip lengths of the liquid on top of the two surfaces. For PS films of thickness between 130 and 230 nm, we find slip lengths between 400 nm and 6 microm, depending on substrate and temperature.
Collapse
Affiliation(s)
- R Fetzer
- Department of Experimental Physics, Saarland University, D-66041 Saarbrücken, Germany
| | | |
Collapse
|
24
|
Xu L, Shi T, Dutta PK, An L. Rim instability by solvent-induced dewetting. J Chem Phys 2007; 127:144704. [DOI: 10.1063/1.2770734] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
25
|
Xu L, Shi T, An L. Nonsolvent-induced dewetting of thin polymer films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:9282-6. [PMID: 17676878 DOI: 10.1021/la700805f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The process of nonsolvent-induced dewetting of thin polystyrene (PS) films on hydrophilic surfaces at room temperature has been studied by using water as a nonsolvent. It is observed that the process of nonsolvent-induced dewetting is greatly different from other previous dewetting processes. The PS film is found in nonviscous state in our study. A mechanism of nonsolvent-induced dewetting is deduced in an order of penetration, replacement, and coalescent, and it is different from other previous dewetting mechanisms. The results of experiments are analyzed from thermodynamics and dynamics to support the hypothetical mechanism.
Collapse
Affiliation(s)
- Lin Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, PR China
| | | | | |
Collapse
|
26
|
Besancon BM, Green PF. Dewetting dynamics in miscible polymer-polymer thin film mixtures. J Chem Phys 2007; 126:224903. [PMID: 17581079 DOI: 10.1063/1.2737043] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Thin polystyrene films supported by oxidized silicon (SiOx/Si) substrates may be unstable or metastable, depending on the film thickness, h, and can ultimately dewet the substrate when heated above their glass transition. In the metastable regime, holes nucleate throughout the film and subsequently grow due to capillary driving forces. Recent studies have shown that the addition of a second component, such as a copolymer or miscible polymer, can suppress the dewetting process and stabilize the film. We examined the hole growth dynamics and the hole morphology in thin film mixtures composed of polystyrene and tetramethyl bisphenol-A polycarbonate (TMPC) supported by SiOx/Si substrates. The hole growth velocity decreased with increasing TMPC content beyond that expected from changes in the bulk viscosity. The authors show that the suppression of the dewetting velocity is primarily due to reductions in the capillary driving force for dewetting and to increased friction at the substrate-polymer interface. The viscosity, as determined from the hole growth dynamics, decreases with decreasing film thickness, and is connected to a depression of the glass transition of the film.
Collapse
Affiliation(s)
- Brian M Besancon
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA
| | | |
Collapse
|
27
|
Yang MH, Hou SY, Chang YL, Yang ACM. Molecular recoiling in polymer thin film dewetting. PHYSICAL REVIEW LETTERS 2006; 96:066105. [PMID: 16606016 DOI: 10.1103/physrevlett.96.066105] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2005] [Indexed: 05/08/2023]
Abstract
The molecular recoiling force stemming from nonequilibrium chain conformation was found to play a very important role in the dewetting stability of polymer thin films. Correct measurements and inclusion of this molecular force into thermodynamic consideration are crucial for analyzing dewetting phenomena and nanoscale polymer chain physics. This force was measured using a simple method based on contour relaxation at the incipient dewetting holes. The recoiling stress was found to increase dramatically with molecular weight and decreasing film thickness. The corresponding forces were calculated to be in the range from 9.0 to 28.2 mN/m, too large to be neglected when compared to the dispersive forces (approximately 10 mN/m) commonly operative in thin polymer films.
Collapse
Affiliation(s)
- M H Yang
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | | | | | | |
Collapse
|
28
|
Bodiguel H, Fretigny C. Viscoelastic dewetting of a polymer film on a liquid substrate. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2006; 19:185-93. [PMID: 16491310 DOI: 10.1140/epje/e2006-00021-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Indexed: 05/06/2023]
Abstract
The Dewetting of thin polymer films (60-300 nm) on a non-wettable liquid substrate has been studied in the vicinity of their glass transition temperature. In our experiment, we observe a global contraction of the film while its thickness remains uniform. We show that, in this case, the strain corresponds to simple extension, and we verify that it is linear with the stress applied by the surface tension. This allows direct measurement of the stress/strain response as a function of time, and thus permits the measurement of an effective compliance of the thin films. It is, however, difficult to obtain a complete viscoelastic characterization, as the short time response is highly dependant on the physical age of the sample. Experimental results underline the effects of residual stress and friction when dewetting is analyzed on rigid substrates.
Collapse
Affiliation(s)
- H Bodiguel
- ESPCI, Laboratoire de Physico-Chimie des Polymères et des Milieux Dispersés, CNRS UMR 7615, 10 rue Vauquelin, 75231, Paris Cedex 05, France
| | | |
Collapse
|
29
|
Roth CB, Dutcher JR. Hole growth in freely standing polystyrene films probed using a differential pressure experiment. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:021803. [PMID: 16196593 DOI: 10.1103/physreve.72.021803] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Revised: 04/19/2005] [Indexed: 05/04/2023]
Abstract
We have probed the whole chain mobility of polymer molecules confined to freely standing films by measuring the flow of gas through holes growing in the films at elevated temperatures using a differential pressure experiment. Freely standing polystyrene films were measured for the temperature range 92 degrees C<T<105 degrees C for films with two different molecular weights Mw=717 x 10(3) and 2240 x 10(3) , with thicknesses 51 nm<h<97 nm . This range of film thicknesses is of particular interest because large reductions in the glass transition temperature Tg have been measured previously for freely standing PS films in this thickness range. We find that hole formation and growth, and therefore substantial chain mobility, does not occur until temperatures close to the bulk value of the glass transition temperature T(bulk)g. The characteristic growth times tau for the thinnest films, which have reduced values of Tg, are not substantially less than those for thicker films, and we find that these small differences in tau can be understood in terms of the bulk phenomenon of shear thinning. We also show that the viscosity at the edge of the hole inferred from the characteristic growth times obtained in this and previous studies exhibit shear thinning with reduced shear strain rates beta that span twelve orders of magnitude.
Collapse
Affiliation(s)
- C B Roth
- Department of Physics and the Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | | |
Collapse
|
30
|
Besancon BM, Green PF. Polystyrene-Based Single-Walled Carbon Nanotube Nanocomposite Thin Films: Dynamics of Structural Instabilities. Macromolecules 2005. [DOI: 10.1021/ma049008+] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
31
|
Besancon BM, Green PF. Moving fronts in entangled polymeric films. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 70:051808. [PMID: 15600647 DOI: 10.1103/physreve.70.051808] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Revised: 08/02/2004] [Indexed: 05/24/2023]
Abstract
Thin liquid films can become structurally unstable and dewet, forming holes which subsequently grow on the substrate. Considerable research has been conducted on the structural evolution and growth of holes, which invariably are shown to be circular. We show that morphologies characterized by circular holes comprise one of three possible morphological regimes. In polystyrene films, supported by silicon oxide substrates, two other regimes are observed with decreasing film thickness. In the second regime, the moving boundary of the growing hole may become unstable and form fingers. The spacing between the fingers is characterized by a well-defined wavelength lambda proportional to h(7/6) M(-1/2) , where h is the film thickness and M is the molecular weight. A dense branchlike morphology characterizes the peripheral regions of the holes in the third regime and is found only in the thinnest films.
Collapse
Affiliation(s)
- Brian M Besancon
- Department of Chemical Engineering and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | | |
Collapse
|
32
|
Wei B, Gurr PA, Genzer J, Qiao GG, Solomon DH, Spontak RJ. Dewetting of Star Nanogel/Homopolymer Blends from an Immiscible Homopolymer Substrate. Macromolecules 2004. [DOI: 10.1021/ma048636o] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bin Wei
- Departments of Chemical & Biomolecular Engineering and Materials Science & Engineering, North Carolina State University, Raleigh, North Carolina 27695, and Polymer Science Group, Department of Chemical & Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia
| | - Paul A. Gurr
- Departments of Chemical & Biomolecular Engineering and Materials Science & Engineering, North Carolina State University, Raleigh, North Carolina 27695, and Polymer Science Group, Department of Chemical & Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia
| | - Jan Genzer
- Departments of Chemical & Biomolecular Engineering and Materials Science & Engineering, North Carolina State University, Raleigh, North Carolina 27695, and Polymer Science Group, Department of Chemical & Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia
| | - Greg G. Qiao
- Departments of Chemical & Biomolecular Engineering and Materials Science & Engineering, North Carolina State University, Raleigh, North Carolina 27695, and Polymer Science Group, Department of Chemical & Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia
| | - David H. Solomon
- Departments of Chemical & Biomolecular Engineering and Materials Science & Engineering, North Carolina State University, Raleigh, North Carolina 27695, and Polymer Science Group, Department of Chemical & Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia
| | - Richard J. Spontak
- Departments of Chemical & Biomolecular Engineering and Materials Science & Engineering, North Carolina State University, Raleigh, North Carolina 27695, and Polymer Science Group, Department of Chemical & Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia
| |
Collapse
|
33
|
Wei B, Genzer J, Spontak RJ. Dewetting behavior of a block copolymer/homopolymer thin film on an immiscible homopolymer substrate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:8659-8667. [PMID: 15379489 DOI: 10.1021/la049562c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Numerous previous studies have established that the addition of a microphase-ordered AB diblock copolymer to a thin homopolymer A (hA) film can slow, if not altogether prevent, film rupture and subsequent film dewetting on a hard substrate such as silica. However, only a few reports have examined comparable phenomena when the hA/AB blend resides on a soft B-selective surface, such as homopolymer B (hB). In this work, the dewetting kinetics of thin films composed of polystyrene (PS) and a symmetric poly(styrene-b-methyl methacrylate) (SM) diblock copolymer on a poly(methyl methacrylate) substrate is investigated by hot-stage light microscopy. Without the SM copolymer, the dewetting rate of the PS layer is constant under isothermal conditions and exhibits Arrhenius behavior with an apparent activation energy of approximately 180 kJ/mol. Addition of the copolymer promotes a crossover from early- to late-stage dewetting kinetics, as evidenced by measurably different dewetting rates. Transmission electron microscopy reveals the morphological characteristics of dewetted PS/SM films as functions of film thickness and SM concentration.
Collapse
Affiliation(s)
- Bin Wei
- Department of Chemical Engineering, North Carolina State University, Raleigh 27695, USA
| | | | | |
Collapse
|
34
|
Lee SH, Yoo PJ, Kwon SJ, Lee HH. Solvent-driven dewetting and rim instability. J Chem Phys 2004; 121:4346-51. [PMID: 15332985 DOI: 10.1063/1.1770475] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An experimental method suitable for reproducible results has been used to investigate dewetting behavior of thin films of solvent-laden polymer. This solvent-driven dewetting enables one to change spreading coefficient by an order of magnitude that is not readily realizable in thermal dewetting and to study polar interactions that have not been fully exploited experimentally. While the film instability is similar to that found in thermal dewetting, the rim instability is quite different. Two different types of the rim instability have been found. With a polar solvent, the rim instability changes from one type to another with increasing film thickness whereas the unstable rim becomes stable for an apolar solvent.
Collapse
Affiliation(s)
- Sarng H Lee
- School of Chemical Engineering, Seoul National University, Seoul 151-744, Korea
| | | | | | | |
Collapse
|
35
|
Xavier JH, Pu Y, Li C, Rafailovich MH, Sokolov J. Transition of Linear to Exponential Hole Growth Modes in Thin Free-Standing Polymer Films. Macromolecules 2004. [DOI: 10.1021/ma034999x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. H. Xavier
- Department of Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794-2275
| | - Y. Pu
- Department of Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794-2275
| | - C. Li
- Department of Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794-2275
| | - M. H. Rafailovich
- Department of Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794-2275
| | - J. Sokolov
- Department of Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794-2275
| |
Collapse
|
36
|
Kargupta K, Sharma A, Khanna R. Instability, dynamics, and morphology of thin slipping films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:244-253. [PMID: 15745028 DOI: 10.1021/la035016s] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Based on the linear stability and nonlinear simulations, we show that the surface instability, dynamics, and morphology of supported thin liquid films are profoundly altered by the presence of slippage on the substrate. A general dispersion equation for flow in slipping thin films is derived and simplified to identify three different regimes of slippage (weak, moderate, and strong) and obtain the length and time scales of instability in them. For illustration, the ubiquitous van der Waals interactions have been employed. Different regimes of slip-flow can be predicted based on a nondimensional parameter, xi, which is a function of slip length, film thickness, intermolecular potential, and interfacial tension. Two distinct transitions from weak to moderate slip and from moderate to strong slip occur at xiT1 approximately 0.01 and xiT2 approximately 500, respectively. More specifically, a decrease in film thickness causes transitions from weak to moderate to strong slip regime. Even a weak slippage causes faster breakup of a thin film, whereas slippage beyond a transition value (slip length, bT1) increases the length scale of instability and reduces the number density of holes compared to the nonslipping case. Strong slippage produces holes faster, and the holes are fewer in number and have less developed rims. The exponents for the length scale (lambdam infinity h0n; h0 is film thickness) and time scale of instability (tr infinity h0m) change nonmonotonically with slippage (for nonretarded van der Waals instability, n E (1.25, 2), m E (3, 6)). Retardation in van der Waals potential increases the exponents (n E (1.5, 2.5), m E (5, 8)). The initial stage of evolution of a slipping film, simulated based on nonlinear equations, follows the length scale and time scale of instability, close to the prediction of linear analysis. It is hoped that the present analysis will help in better interpretation of thin film experiments, in estimation of slippage, and in the determination of intermolecular forces from the length and time scales of the instability.
Collapse
Affiliation(s)
- Kajari Kargupta
- Department of Chemical Engineering, Jadavpur University, Kolkata-700032, India.
| | | | | |
Collapse
|
37
|
Damman P, Baudelet N, Reiter G. Dewetting near the glass transition: transition from a capillary force dominated to a dissipation dominated regime. PHYSICAL REVIEW LETTERS 2003; 91:216101. [PMID: 14683320 DOI: 10.1103/physrevlett.91.216101] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2003] [Indexed: 05/24/2023]
Abstract
Dynamics and corresponding morphology of dewetting of thin polystyrene films at temperatures close to the glass transition were investigated by measuring simultaneously dewetted distance and width of the rim. Comparing the opening of cylindrical holes with the retraction of a straight contact line revealed (i). a drastic influence of the geometry (planar or radial symmetry) on the dynamics at early stages, (ii). a new logarithmic dewetting regime, and (iii). transitions between four dewetting regimes clearly indicated by changes in the shape of the rim. The complete dewetting scenario can be understood as an initial dominance of capillary driving forces, which is progressively overtaken by dissipation related to the increasing size of the rim.
Collapse
Affiliation(s)
- Pascal Damman
- Laboratoire de Physicochimie des Polymeres, Université de Mons Hainaut, 20, Place du Parc, B-7000 Mons, Belgium.
| | | | | |
Collapse
|
38
|
Bollinne C, Cuenot S, Nysten B, Jonas AM. Spinodal-like dewetting of thermodynamically-stable thin polymer films. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2003; 12:389-396. [PMID: 15007766 DOI: 10.1140/epje/e2004-00007-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Energetic considerations indicate that long-range Van der Waals forces stabilize thin polystyrene (PS) films against height fluctuations on silicon substrates. Nevertheless, we report here on the amplification of capillary waves of specific wavelengths for 15 nm thick PS films on silicon, ultimately leading to dewetting in a "spinodal-like" process. However, the temporal dependence of the wavelength of the growing instability does not agree with the "classical" spinodal dewetting mechanism. Therefore, this phenomenon is ascribed to the existence of "structural" forces resulting either from the restructuring of the films or from density variations within the films during annealing, in accordance with recent theoretical treatments. The process is shown not to be limited to polystyrene films, which indicates the generality of our findings.
Collapse
Affiliation(s)
- C Bollinne
- Unité de Physique et de Chimie des Hauts Polyméres (POLY) and Research Centre in Micro- and Nanoscopic Materials and Electronic Devices (CeRMiN), Université catholique de Louvain, Croix du Sud 1, 1348 Louvain-la-Neuve, Belgium
| | | | | | | |
Collapse
|
39
|
Yin J, Guo Q, Palmer RE, Bampos N, Sanders JKM. Supramolecular Monolayers of Zinc Porphyrin Trimers on Graphite. J Phys Chem B 2002. [DOI: 10.1021/jp026490u] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
40
|
Masson JL, Olufokunbi O, Green PF. Flow Instabilities in Entangled Polymer Thin Films. Macromolecules 2002. [DOI: 10.1021/ma020161i] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jean-Loup Masson
- Texas Materials Institute and Chemical Engineering Department, The University of Texas at Austin, Austin, Texas 78712
| | - Okikiolu Olufokunbi
- Texas Materials Institute and Chemical Engineering Department, The University of Texas at Austin, Austin, Texas 78712
| | - Peter F. Green
- Texas Materials Institute and Chemical Engineering Department, The University of Texas at Austin, Austin, Texas 78712
| |
Collapse
|