Equilibrium Pathway of Spin-Coated Polymer Films

Tsui, Ophelia Kwan Chui; Wang, Yongjian; Lee, Fuk Kay; Lam, Chi Hang; Yang, Zhaohui

doi:10.1021/ma702374g

Cited by 45 publications

(87 citation statements)

References 27 publications

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“…The former is consistent with a recent viscosity measurement of 18 nm PS films by time-resolved AFM. 109 If this behavior indeed reflects τ −1 (T), as tentatively suggested by the authors, 108 the physics of thin film T g may require ideas different from the ones suggested so far. On the basis of the above discussions, obtaining a measurement of τ(T) for films much thinner than 20 nm would be important for understanding the anomalous dynamics of polymer films.…”

Section: Concluding Remark and Outlookmentioning

confidence: 86%

Anomalous Dynamics of Polymer Films

Tsui

2008

Series in Soft Condensed Matter

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This chapter reviews the recent experiments involving the dynamics of polymer films with thickness comparable to the gyration radius of the polymer, which overwhelmingly show that their glass transition temperature, T g , depends on the film thickness and can sometimes differ significant from that of the bulk. The greatest mystery is the onset film thickness of this phenomenon being ~50 nm, much larger than the typical cooperativity size (~3 nm) of glass transition. While the sliding chain model [De Gennes, Eur. Phys. J. E (2000)] can qualitatively explain the results of the high molecular weight (M w ) freely-standing films, it fails to account for those of the low-M w freely-standing films and the supported films. For the latter two, at least two theories, i.e., the percolation theory [Long et al., ibid (2001)] and surface capillary wave theory [Herminghaus et al., ibid (2001)] have been proposed that can account for the observed thickness dependence of thin film T g . However, experimental data available at this time do not allow the theories to be distinguished. We briefly outline the physical ideas of these theories, and delineate how dynamical measurements of nanometer thick films may provide important insights about the problem.

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Section: Concluding Remark and Outlookmentioning

confidence: 86%

Anomalous Dynamics of Polymer Films

Tsui

2008

Series in Soft Condensed Matter

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“…Previous studies have examined the time course of entanglement formation in spin-coated globular polystyrene (PS) thin films on silicon wafers, on which the formation of entanglements was delayed by the substrate effect. [4][5][6][7][8] fewer entanglements than PS films fabricated by normal methods. 9,10 Therefore, globular solids may be temporarily fabricated in the spin-coated PS thin films.…”

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confidence: 90%

“…The relationship between a and the fractal dimension is a5d f (8) for mass fractals where d f is the mass fractal dimension and a 5 62d s (9) for surface fractals where d s is the surface fractal dimension. 35,36 The a values obtained in this study were in the range 3 < a < 4, which indicated that scattering was from surface fractal geometry.…”

Section: Solid State Properties Mechanical Propertiesmentioning

confidence: 99%

Morphology and properties of globular polymeric materials in the solid state: A composite material of DNA with a cationic surfactant

Ossai

Tomimori

Ohki

et al. 2015

J. Polym. Sci. Part B: Polym. Phys.

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The aim of the present study was to control entanglements in order to regulate the properties of polymeric solids. Initially, fabrication of polymeric solids with few entanglements was attempted. Films of the DNA-cationic surfactant, cetyltrimethylammonium bromide (CTAB) (DNA-CTA), were cast from ethanol solution at room temperature. Morphological examination of DNA-CTA complex films using atomic force microscopy (AFM) revealed that these films were constructed by particle-like substances. Geometrical analysis of AFM images showed that the particle-like substances were the aggregates of several DNA-CTA globules. Mechanical characterization suggested that there were fewer entanglements than with normal plastic films. Small angle X-ray scattering experiments during annealing indicated that molecular motions were highly excited in the surface region of each particle. In conclusion, a globular polymeric film with fewer entanglements was fabricated. V C 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 730-738 KEYWORDS: cationic surfactant; DNA; entanglements; globular solid; mechanical properties INTRODUCTION Interactions in polymer chain systems involve both electrostatic and geometrical interactions. As the concentration of polymer molecules in a solution increase during the preparation of polymeric solids by, for example, casting, the interpenetration of polymer chains occurs and entanglements, representing the geometrical interaction, are constructed provided the molecular weight of the polymer is greater than the critical molecular weight for entanglement. These entanglements result in homogeneous solid properties with a characteristic relaxation spectrum. The solid state properties of polymeric materials change with temperature and molecular weight, and are governed by the quantity and quality of the entanglements.1-3 The amount of chain entanglements is auto-

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“…In addition, the highly non-equilibrium glassy state of polymeric films can be affected by high spin speeds or rapid solvent evaporation [24,25]. These may cause polymer chains to orient in preferential directions.…”

Section: Introductionmentioning

confidence: 99%

Optical anisotropy, molecular orientations, and internal stresses in thin sulfonated poly(ether ether ketone) films

2015

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The thickness, the refractive index, and the optical anisotropy of thin sulfonated poly(ether ether ketone) films, prepared by spin-coating or solvent deposition, have been investigated with spectroscopic ellipsometry. For not too high polymer concentrations (B5 wt%) and not too low spin speeds (C2000 rpm), the thicknesses of the films agree well with the scaling predicted by the model of Meyerhofer, when methanol or ethanol are used as solvent. The films exhibit uniaxial optical anisotropy with a higher in-plane refractive index, indicating a preferred orientation of the polymer chains in this in-plane direction. The radial shear forces that occur during the spin-coating process do not affect the refractive index and the extent of anisotropy. The anisotropy is due to internal stresses within the thin confined polymer film that are associated with the preferred orientations of the polymer chains. The internal stresses are reduced in the presence of a plasticizer, such as water or an organic solvent, and increase to their original value upon removal of such a plasticizer.

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Equilibrium Pathway of Spin-Coated Polymer Films

Cited by 45 publications

References 27 publications

Anomalous Dynamics of Polymer Films

Anomalous Dynamics of Polymer Films

Morphology and properties of globular polymeric materials in the solid state: A composite material of DNA with a cationic surfactant

Optical anisotropy, molecular orientations, and internal stresses in thin sulfonated poly(ether ether ketone) films

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