Effect of Long Range Interactions on the Glass Transition Temperature of Thin Polystyrene Films

Zhang, Cui; Fujii, Yoshihisa; Tanaka, Keiji

doi:10.1021/mz300391g

Cited by 58 publications

(49 citation statements)

References 52 publications

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“…However, within experimental accuracy, this value was the same as that for PS-H at 392 K. In addition, the T g for the 20-nm-thick film on silicon was determined by examining its thickness as a function of temperature via ellipsometry. 44 The values obtained for PS-H and PS-N were again identical (Supplementary Figure S2). Thus, it can be concluded that the segmental mobility in the interfacial region, at least within this depth range, was not restricted by the introduction of the functional end group.…”

Section: Interfacial Chain Mobilitysupporting

confidence: 55%

Stabilization of polystyrene thin films by introduction of a functional end group

Shimomura

Inutsuka

Tajima

et al. 2016

Polym J

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The thin film stabilities of ω-N-(3-(dimethylamino)propyl)propylamide-terminated polystyrene (PS-N) and its blends with conventional polystyrene (PS-H) supported on silicon wafers with a native oxide layer were examined. Whereas a 20-nm-thick film of PS-H with a number-average molecular weight of ∼ 50k decomposed at 423 K, a comparable PS-N film and blended films containing a PS-N fraction of 440 wt% were stable. Although the local conformation of chains at the substrate interface was not the same for PS with and without the functional end group, the glass transition temperature at the interface was identical for both PS-H and PS-N. The residual adsorbed layer on the substrate after washing the films with a good solvent was thicker for PS-N than for PS-H. This implies that end functionalization, rather than segmental dynamics, affects chain movement on a large scale.

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Section: Interfacial Chain Mobilitysupporting

confidence: 55%

Stabilization of polystyrene thin films by introduction of a functional end group

Shimomura

Inutsuka

Tajima

et al. 2016

Polym J

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“…61,93 The stronger attractive interaction between PS and H-Si is also supported by solvent leaching experiments of the supported PS film with toluene, which show that the thickness of the residual PS layer on H-Si is higher than that on SiO x -Si. It has been shown that hydrogen-terminated Si is more strongly adsorbed by PS than SiO x , 61,93 due to higher thermodynamic work of adhesion 57 and the positive interfacial potential.…”

Section: Investigation Of the Rheological Behavior Of Supported Thin mentioning

confidence: 76%

Probing the rheological properties of supported thin polystyrene films by investigating the growth dynamics of wetting ridges

et al. 2016

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Despite its importance in the processing of nanomaterials, the rheological behavior of thin polymer films is poorly understood, partly due to the inherent measurement challenges. Herein, we have developed a facile method for investigating the rheological behavior of supported thin polymeric films by monitoring the growth of the "wetting ridge"-a microscopic protrusion on the film surface due to the capillary forces exerted by a drop of ionic liquid placed on the film surface. It was found that the growth dynamics of the wetting ridge and the behavior of polystyrene rheology are directly linked. Important rheological properties, such as the flow temperature (Tf), viscosity (η), and terminal relaxation time (τ0) of thin polystyrene films, can be derived by studying the development of the height of the wetting ridge with time and the sample temperature. Rheological studies using the proposed approach for supported thin polystyrene (PS) films with thickness down to 20 nm demonstrate that the PS thin film exhibits facilitated flow, with reduced viscosity and lowered viscous temperature and a shortened rubbery plateau, when SiOx-Si was used as the substrate. However, sluggish flow was observed for the PS film supported by hydrogen-passivated silicon substrates (H-Si). The differences in enthalpic interactions between PS and the substrates are the reason for this divergence in the whole-chain mobility and flow ability of thin PS films deposited on SiOx-Si and H-Si surfaces. These results indicate that this approach could be a reliable rheological probe for supported thin polymeric films with different thicknesses and various substrates.

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“…For example, it is well established that for supported films of linear polymer chains, T g decreases as a function of decreasing thickness in cases where there is little or no interaction between polymer and substrate, e.g., polystyrene (PS) films supported on Si/SiO x . 7,[10][11][12]16,17,34 In contrast, an increase in T g with confinement is observed in systems with sufficiently large attractive polymer-substrate interactions, e.g., poly(methyl methacrylate) (PMMA) films supported on Si/SiO x . 8,13,19 Any attempt to draw comparisons between the effects of different substrates on DSC-determined T g -confinement behavior in supported, ultrathin polymer films would be exceedingly complex.…”

Section: Introductionmentioning

confidence: 99%

Poly(methyl methacrylate) nanotubes in AAO templates: Designing nanotube thickness and characterizing the T-confinement effect by DSC

Tan

Torkelson

2016

Polymer

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We used differential scanning calorimetry (DSC) to study the effect of confinement on the glass transition temperature (T g) of poly(methyl methacrylate) (PMMA) nanotubes supported in anodic aluminum oxide (AAO) templates. We created nanotubes by wetting templates with polymer melts and developed a design equation relating tube thickness (t tube) with bulk radius of gyration (R g): (t tube ≈ 2 R g + 9 nm). The results indicate that t tube depends on overall conformation and size of the polymer coils and can be tuned at the nanoscale by polymer molecular weight. The T g of AAO template-supported PMMA nanotubes increases with decreasing t tube , with T g,tube-T g,bulk = 12 K in 18-nm-thick nanotubes; we attribute the T g increase to hydrogen bonds between PMMA ester side groups and hydroxyl groups on the surface of the γ-Al 2 O 3 templates. Using ellipsometry, we characterized T g-confinement effects for PMMA films supported on Si/SiO x , sputtered Al 2 O 3 and sapphire (α-Al 2 O 3). Films supported on substrates with higher concentrations of surface hydroxyl groups (α-Al 2 O 3 > sputtered-Al 2 O 3 > Si/SiO x) exhibit larger T g-confinement effects. The DSC-determined T g enhancements for nanotubes supported in γ-Al 2 O 3 templates fall between the ellipsometry-determined T g enhancements determined for PMMA films on α-Al 2 O 3 and those for films on sputtered-Al 2 O 3. These results show that molecular weight provides for tunability of polymer nanotube thickness in AAO templates, that there is excellent agreement in confinement effects measured by DSC and by ellipsometry, and that T g can be tuned by modulating the levels of interfacial, polymer-substrate interactions by using surfaces with different chemical or crystallographic properties.

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Effect of Long Range Interactions on the Glass Transition Temperature of Thin Polystyrene Films

Cited by 58 publications

References 52 publications

Stabilization of polystyrene thin films by introduction of a functional end group

Stabilization of polystyrene thin films by introduction of a functional end group

Probing the rheological properties of supported thin polystyrene films by investigating the growth dynamics of wetting ridges

Poly(methyl methacrylate) nanotubes in AAO templates: Designing nanotube thickness and characterizing the T-confinement effect by DSC

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