Nanoparticle Induced Morphology Modulation in Spin Coated PS/PMMA Blend Thin Films

Das, Anuja; Dey, Arka Bikash; Chattopadhyay, Shreyasi; De, Goutam; Sanyal, M. K.; Mukherjee, Rabibrata

doi:10.1021/acs.langmuir.0c02584

Cited by 19 publications

(18 citation statements)

References 46 publications

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“…It is well-known that a PS-PMMA blend consists of laterally-separated PS-and PMMA-rich phases at ambient conditions. 7,[39][40][41][42][43][44] Herein, using correlative topographical, molecular, and elemental information, we demonstrate that besides the previously-observed lateral phase separation, a vertical phase separation also takes place at the top ca. 20 nm of the PS-PMMA blend surface.…”

Section: Introductionmentioning

confidence: 49%

Visualizing Surface Phase Separation in PS PMMA Polymer Blends at the Nanoscale

Mrđenović

Abbot

Mougel

et al. 2022

Preprint

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Phase-separated polymer blend films are an important class of functional materials with numerous technological applications including solar cells, catalysis, and biotechnology. These technologies are underpinned by precise control of phase separation at the nanometer length-scales, which is highly challenging to visualize using conventional analytical tools. Herein, we introduce tip-enhanced Raman spectroscopy (TERS), in combination with AFM, confocal Raman spectroscopy, and XPS, as a sensitive nanoanalytical method to determine lateral and vertical phase-separation in polystyrene (PS)-poly(methyl methacrylate) (PMMA) polymer blend films. Correlative topographical, molecular, and elemental information reveals a vertical phase separation of the polymers within the top ca. 20 nm of the blend surface in addition to the lateral phase separation in the bulk. Furthermore, complementary TERS and XPS measurements reveal the presence of PMMA within 9.2 nm of the surface and PS at the sub-surface of the polymer blend. This fundamental work establishes TERS as an powerful analytical tool for surface characterization of this important class of polymers at nanometer length-scales.

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Section: Introductionmentioning

confidence: 49%

Visualizing Surface Phase Separation in PS PMMA Polymer Blends at the Nanoscale

Mrđenović

Abbot

Mougel

et al. 2022

Preprint

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“…When thiol-capped AuNP is spin coated along with PS from toluene, it migrates to the free surface during spin coating itself, which has been recently shown by us based on X-ray photoelectron spectroscopy and X-ray scattering …”

Section: Discussionmentioning

confidence: 82%

“…Before we try to explain some of the unique findings on dewetting of NP-containing PS thin films, we would like to highlight certain important and critical issues which are already known and are likely to facilitate subsequent discussion: In TA-mediated dewetting of NP-containing PS films, it has been shown that the particles migrate to the substrate only when the surface energy of the substrate (γ S ) is higher than that of the particles, provided the particles are dispersed in the film When thiol-capped AuNP is spin coated along with PS from toluene, it migrates to the free surface during spin coating itself, which has been recently shown by us based on X-ray photoelectron spectroscopy and X-ray scattering Based on Flory–Huggin’s interaction parameter (χ parameter), it can be seen that the thiol-capped AuNPs are not compatible with both PS and chloroform.…”

Section: Discussionmentioning

confidence: 99%

“…58 (2) When thiol-capped AuNP is spin coated along with PS from toluene, it migrates to the free surface during spin coating itself, which has been recently shown by us based on X-ray photoelectron spectroscopy and X-ray scattering. 76 (3) Based on Flory−Huggin's interaction parameter (χ parameter), it can be seen that the thiol-capped AuNPs are not compatible with both PS and chloroform. However, based on the values of χ and χ cr , we note that the particles are less incompatible in chloroform as compared to PS (see Section S8 for χ values for each interaction).…”

Section: ■ Discussionmentioning

confidence: 99%

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Feature Size Modulation in Dewetting of Nanoparticle-Containing Ultrathin Polymer Films

Das

Mukherjee

2021

Macromolecules

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Ultrathin polymer films (thinner than ∼100 nm) undergo spontaneous rupture on a non-wetting surface with the appearance of random holes due to interfacial van der Waal’s interaction or disjoining pressure. These holes grow in size and coalesce into threadlike morphology, which subsequently disintegrate in an isotropic array of nearly equal-sized droplets, the size (d D) and periodicity (λD) of which scales with the initial film thickness (h F). We show that both λD and d D of the dewetted droplets can be modulated by adding trace amounts of nanoparticles (NPs) in the films. While addition of higher proportion of NPs is known to stabilize the films against dewetting, the presence of a lower amount of NPs leads to non-monotonic variation of λD and d D with h F, with the possible creation of miniaturized dewetted features under certain conditions. We also show that λD and d D of the dewetted films depend on whether dewetting is engendered by thermal annealing of the film beyond the glass transition temperature of the constituent polymer (T G) or by exposing the film to solvent vapor (SV). Our findings reveal that both λD and d D are much larger when the film (both with and without particles) is dewetted in the SV atmosphere, arguably due to penetration of the solvent into the film matrix, resulting in an increase in the effective thickness of the film during dewetting. We show that in SV-mediated dewetting, the much faster dynamics is attributed to solvent penetration through the film and its wetting the substrate, rather than a drastic drop in viscosity. We also observe that SV exposure not only leads to much faster dewetting dynamics, but it also successfully engenders dewetting in films with higher h F, which remain stable when annealed thermally.

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“…[3][4][5][6][7][8][9][10][11] This includes studies on bulk miscible polymer blends, as well as polymer blends nanoconfined in thin films as well as thin films of polymer films with embedded nanoparticles. 12 In general, blending of miscible polymers leads to a distribution of spatial compositions on the nanoscale, which are deviating from that of the bulk averaged concentration. [13][14][15] This does not only influence properties like glassy dynamics, [9][10][11]15,16 glass transition and fragility (see for instance ref.…”

Section: Introductionmentioning

confidence: 99%