Dewetting Dynamics at a Polymer−Polymer Interface

Qu, S.; Clarke, C. J. S.; Liu, Y.; Rafailovich, Miriam; Sokolov, Jonathan; Phelan, K. C.; Krausch, Georg

doi:10.1021/ma961297h

Cited by 86 publications

(124 citation statements)

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“…We use a technique developed by Qu et al 10 where we observe the rate of dewetting in polymer bilayer films and apply the theory of Brochard-Wyart et al 11 to extract the viscosity of the films. We show that even in the case where particles are well dispersed in the films, large effects on the stability of the film due to dewetting may be induced by the addition of fillers.…”

Section: Introductionmentioning

confidence: 99%

“…In this case, known as the "solidlike lower layer regime", the viscosity is given by where cos θ e ) (γ B -γ AB )/γ A . Hence, if the parameters in eq 2 are known for a given set of polymers, Qu 10 has shown that one can use eq 2 to determine the viscosity of the film. Here we use this technique to compare the effect of adding fillers into the homopolymer film's viscosity.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Nanoscopic Fillers on Dewetting Dynamics

et al. 2006

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We synthesized C 18 -functionalized gold and palladium nanoparticles with average diameter size of 10 and 3 nm, respectively, and carried out a systematic study of the effect of nanoscale metallic fillers on the dewetting dynamics of PS/PMMA bilayer substrates. Optical and atomic force microscopies were used to study the hole growth and determine the viscosity of the films as a function of PS molecular weight, particle radius, and concentration. Neutron reflectivity was used to measure the effects of the nanoparticles on the tracer diffusion coefficient. X-ray reflectivity and TEM microscopy were used to study the distribution of the particles within the film and ensure that no segregation or clustering occurred. The results indicated that the dynamics are a sensitive function of the ratio between the filler radius, R particle , and the polymer radius of gyration, R g . The data were found to collapse on a universal curve where the relative velocity of the filled system was faster than that for the unfilled system when R g /R particle > 4 and slower when R g /R particle < 4. Shear modulation force microscopy method (SMFM) measurements were performed as a function of temperature and indicated that T g was depressed by 12°C relative to the bulk when R g /R panrticle > 4 and unchanged when R g /R particle < 4. The results were interpreted in terms of an increase in the local excluded volume and possible elastic distortions of the polymer matrix. IntroductionNanoscale noble metal and metal oxide particles have been added to polymers for years to significantly enhance various properties such as UV absorption, electrical conductivity, and optical dispersion. 1-3 In contrast to bulk fillers, such as carbon black or silica, which are added in large quantities in order to reinforce structural properties, 4 the concentration of metallic particles required to affect the electronic response is often less than 5%. Therefore, it has always been assumed that these metal fillers have no effect on the rheological or mechanical properties. Furthermore, since these nanoparticles are coated with surfactants used as dispersants, it has been assumed that they do not interact with the polymer chains and hence do not affect properties such as viscosity, glass transition, or interfacial tensions. Thus, not much attention has been given to the effect of fillers on film stability, which is governed only by known differences in the surface and interfacial energy of the polymers.Recently, several authors have shown that dewetting can be greatly affected when strong interactions exist between the fillers and the substrate or the polymer matrix. Barnes et al. 5 have shown that the addition of C 60 can stabilize homopolymer films against dewetting. In this case, segregation of the C 60 filler to the substrate created a surface, which interacted strongly with the polymer and suppressed dewetting by pinning the polymer chains. This situation was also modeled by Gersappe et al. 6 Sharma et al. 7 have shown that when the filler interacts...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Nanoscopic Fillers on Dewetting Dynamics

et al. 2006

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“…Recently, much attention has been paid to the dewetting behaviour of poly(styrene) (PS) films on silicon or on another polymer [4][5][6][7][8][9][10][11][12], such as rubbery poly(dimethyl siloxane) (PDMS) [1,11,12]. In other studies, the spinodal dewetting of thin poly(methyl methacrylate) (PMMA) films deposited on a PS substrate has been extensively investigated [13,14,3].…”

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Structural relaxation of spin-cast glassy polymer thin films as a possible factor in dewetting

et al. 2003

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Reiter [1] has recently reported a situation in which the dewetting of quasi-solid films is linked plastic deformation -rather than viscous flow -resulting from capillary forces. Herein we propose that, in thin films of some glassy polymers -especially poly(methyl methacrylate) (PMMA) -prepared by spin-casting from solvent, structural relaxation might impart sufficient stress to cause plastic deformation. We find that PMMA films decrease in thickness by several percent, which is sufficient to create significant stress in those cases in which the film is attached to a rigid substrate. The floating technique, which can take tens of minutes, might allow most of the structural relaxation to occur prior to dewetting experiments.

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“…The ''pancake-like'' droplets evidently have anisotropic structure. The interface characteristic is similar to that of PS dewetting on PMMA surface, 11,12 although the final patterns have big differences possibly due to strong shear force from dewetting and phase separation. The AFM images indicate that the interface deformation is highly localized near the contact line.…”

Section: Resultsmentioning

confidence: 62%

“…[9][10][11][12] This report studies the phase separation and dewetting of PS and PMMA blend films with different thickness, using optical video microscopy in situ during annealing. For the first time, we report the interface characteristic of PS/PMMA in the final stage of phase separation.…”

Section: Introductionmentioning

confidence: 99%

Phase Separation and Dewetting Induced Surface Pattern in PS/PMMA Blend Films

Xiong

Shi

Tian

2005

Polym J

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ABSTRACT:The pattern evolution of phase separation and dewetting of PS/PMMA blend thin films at 160 C were observed by optical video microscopy and atomic force microscopy (AFM). The results show that the PMMA wetting component is driven toward the substrate, and the PS dewetting component is driven toward the surface by pressure caused by phase separation and wetting. At the late stage of the process, irregular shapes of PS islands evolve into round droplets. A cross-section of the interface between the PS and PMMA after phase separation was observed by AFM for the first time. This shows that the PS component extends considerably into the PMMA substrate layer and a trench was observed inside and outside the PMMA rim, respectively. This confirms the notion of a deformable interface between the two materials. [DOI 10.1295/polymj.37.560] KEY WORDS PS/PMMA Blend Films / Phase Separation / Dewetting / The structure and properties of thin blend films are governed by interplay between phase separation and surface segregation driven by polymer-surface interactions. This is important for applications because commercial films are normally comprised of multiple polymer species, solvent, and additives, leading to numerous complex phase separation morphologies and film properties. As a function of blend composition and polymer-polymer interaction parameter different phase separation morphologies have been observed in bulk samples. In the state of a thin film, with a thickness below a critical film thickness, the surface directed spinodal decomposition of polymers is suppressed and phase separation perpendicular to the interface results. The interplay between phase separation and dewetting increases the variety of accessible surface morphologies. The time scales of dewetting and phase separation are different and depend on the internal interaction.1-8 However, understanding of phase evolution in blend films has not yet been achieved in details, in part due to the complex interplay between wetting, phase separation, capillary fluctuations and coarsening and roughening, respectively.Polystyrene (PS) and poly(methylmethacrylate) (PMMA) are classic model systems in polymer science, and numerous studies have been recently been undertaken. [9][10][11][12] This report studies the phase separation and dewetting of PS and PMMA blend films with different thickness, using optical video microscopy in situ during annealing. For the first time, we report the interface characteristic of PS/PMMA in the final stage of phase separation. EXPERIMENTALFirst, PS and PMMA were dissolved in toluene. The polymers had molecular weights M w ¼ 60500 g/mol (PS), and M w ¼ 62500 g/mol (PMMA) and polydispersities M w =M n ¼ 1:07 (PS) and M w =M n ¼ 1:12 (PMMA). The total polymer concentration was prepared first at 3% and then part of the solution was diluted to 2% and 1%. The PS mass fraction was fixed at 0.50. Thin films of the polymer blends were formed by placing a droplet of the solution onto 1 cm Â 1 cm Si(001) with the native oxide layer present (...

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Dewetting Dynamics at a Polymer−Polymer Interface

Cited by 86 publications

References 14 publications

Effect of Nanoscopic Fillers on Dewetting Dynamics

Effect of Nanoscopic Fillers on Dewetting Dynamics

Structural relaxation of spin-cast glassy polymer thin films as a possible factor in dewetting

Phase Separation and Dewetting Induced Surface Pattern in PS/PMMA Blend Films

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