Kinetics of dispersion of nanoparticles in thin polymer films at high temperature

Begam, Nafisa; Chandran, Sivasurender; Biswas, Nupur; Basu, J. K.

doi:10.1039/c4sm02383h

Cited by 11 publications

(12 citation statements)

References 69 publications

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“…The results presented in this letter are based on thin films (thickness, h, ∼ 65-70 nm; Table S2 [27]) of PS of two different molecular weights (100kDa and 50kDa), embedded with PGNPs having two different grafted chain molecular weights (3kDa and 20kDa) synthesized using the methods discussed earlier [28][29][30]. These PGNPs were dispersed in linear PS at 0.5% volume fraction of the gold core.…”

Section: Methodsmentioning

confidence: 99%

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Nanoparticle–polymer interfacial layer properties tune fragility and dynamic heterogeneity of athermal polymer nanocomposite films

Begam

Chandran

et al. 2018

Soft Matter

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Enthalpic interactions at the interface between nanoparticles and matrix polymers is known to influence various properties of the resultant polymer nanocomposites (PNC). For athermal PNCs, consisting of grafted nanoparticles embedded in chemically identical polymers, the role and extent of the interface layer (IL) interactions in determining the properties of the nanocomposites is not very clear. Here, we demonstrate the influence of the interfacial layer dynamics on the fragility and dynamical heterogeneity (DH) of athermal and glassy PNCs. The IL properties are altered by changing the grafted to matrix polymer size ratio, f , which in turn changes the extent of matrix chain penetration into the grafted layer, λ. The fragility of PNCs is found to increase monotonically with increasing entropic compatibility, characterised by increasing λ. Contrary to observations in most polymers and glass formers, we observe an anti-correlation between the dependence on IL dynamics of fragility and DH, quantified by the experimentally estimated Kohlrausch-Watts-Williams parameter and the non-Gaussian parameter obtained from simulations.

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Section: Methodsmentioning

confidence: 99%

“…These PGNPs were dispersed in linear PS at 0.5% volume fraction of the gold core. Details of samples are provided in the supplemental information (SI) [27] as well in our earlier studies [28,29] and summarized in Table 1.…”

Section: Methodsmentioning

confidence: 99%

Nanoparticle–polymer interfacial layer properties tune fragility and dynamic heterogeneity of athermal polymer nanocomposite films

Begam

Chandran

et al. 2018

Soft Matter

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“…The mobility and the spatial arrangement of NPs can be crucial to controlling the properties of polymer composites such as the pattern and the wetting stability. ,− The mobility of NPs determined the kinetics of the pattern-directed phase separation of AuPS/PMMA blended films, which was critical to the imprinted pattern of the films. , It is, however, a formidable task to investigate the trajectories and diffusion of NPs in the polymer film in experiments due to the limited spatial resolution. Molecular simulations may shed light on the diffusion mechanism of NPs in thin polymer films. , In this study, we investigate the detailed diffusion mechanism of NPs in the free-standing thin polymer film.…”

Section: Introductionmentioning

confidence: 99%

Spatial Dependence of Non-Gaussian Diffusion of Nanoparticles in Free-Standing Thin Polymer Films

Jung

Kwon

et al. 2019

J. Phys. Chem. B

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The addition of nanoparticles (NPs) to a free-standing polymer film affects the properties of the film such as viscosity and glass transition temperature. Recent experiments, for example, showed that the glass transition temperature of thin polymer films was dependent on how NPs were distributed within the polymer films. However, the spatial arrangement of NPs in free-standing polymer films and its effect on the diffusion of NPs and polymers remain elusive at a molecular level. In this study, we employ generic coarse-grained models for polymers and NPs and perform extensive molecular dynamics simulations to investigate the diffusion of polymers and NPs in free-standing thin polymer films. We find that small NPs are likely to stay at the interfacial region of the polymer film, while large NPs tend to stay at the center of the film. On the other hand, as the interaction between a NP and a monomer becomes more attractive, the NP is more likely to be placed at the film center. The diffusion of monomers slows down slightly as more NPs are added to the film. Interestingly, the NP diffusion is dependent strongly on the spatial arrangement of the NPs: NPs at the interfacial region diffuse faster and undergo more non-Gaussian diffusion than NPs at the film center, which implies that the interfacial region would be more mobile and dynamically heterogeneous than the film center. We also find that the mechanism for non-Gaussian diffusion of NPs at the film center differs from that at the interfacial region and that the NP diffusion would reflect the local viscosity of the polymer films.

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“…In particular the presence of the surface imposes confinement of the chain motion perpendicular to the surface, whereas for a free surface the motion parallel to the surface has less constraints than in the bulk. Such dynamical anisotropy at a free polymer surface has recently been observed experimentally in the diffusion of nanoparticles embedded in a PS film [24] where in-plane diffusion was found to be many orders of magnitude faster than out-ofplane diffusion. The faster motion parallel to the surface outweighs the suppression of the perpendicular motion resulting in the overall depression of T g near the surface.…”

Section: Data For Pdmsmentioning

confidence: 93%

Nanoscale depth-resolved polymer dynamics probed by the implantation of low energy muons

Pratt

Lancaster

Baker

et al. 2016

Polymer

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(2016) 'Nanoscale depth-resolved polymer dynamics probed by the implantation of low energy muons. ', Polymer., Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe low energy muon (LEM) technique has been used to probe local changes in the dynamical spectrum of thin film polymer samples taking place as a function of the temperature and the implantation depth below the free surface. The studies have been made on samples of polydimethylsiloxane (PDMS) and polybutadiene (PB) using the transverse magnetic field (TF) configuration and diamagnetic probe muons. In PDMS evidence is found for suppression of the glass transition temperature near the surface, along with significantly modified dynamics in the near-surface region as well as at depths significantly below the surface. For PB the LEM technique reveals well-defined layers of dynamical and spatial inhomogeneity at depths of order 0.1 to 0.2 µm below the free surface. These inhomogeneous regions may be assigned to nanopores produced by solvent streaming during preparation of spin-cast films. A thermal annealing procedure is shown to significantly reduce the thickness of these inhomogeneous layers. These results demonstrate that using LEM in the TF configuration provides a promising new method for studying surface-modified local dynamics of polymers that is also able to reveal nanostructured buried layers in polymer films.

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Kinetics of dispersion of nanoparticles in thin polymer films at high temperature

Cited by 11 publications

References 69 publications

Nanoparticle–polymer interfacial layer properties tune fragility and dynamic heterogeneity of athermal polymer nanocomposite films

Nanoparticle–polymer interfacial layer properties tune fragility and dynamic heterogeneity of athermal polymer nanocomposite films

Spatial Dependence of Non-Gaussian Diffusion of Nanoparticles in Free-Standing Thin Polymer Films

Nanoscale depth-resolved polymer dynamics probed by the implantation of low energy muons

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