Equilibration of Polymer Films Cast from Solutions with Different Solvent Qualities

Li, Ranxing Nancy; Clough, A. R.; Yang, Zhaohui; Tsui, Ophelia Kwan Chui

doi:10.1021/ma202612q

Cited by 40 publications

(58 citation statements)

References 24 publications

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“…Indeed, understanding the dynamics and stability of thin films is essential to technological applications such as nanolithography 4,5 and the development of non-volatile memory storage devices 6 . Moreover, thin films have enabled the study of the effect of confinement on polymers [7][8][9][10][11][12][13][14][15][16] . Several experiments have been performed in order to gain insights into the dynamics of these films.…”

Section: Introductionmentioning

confidence: 99%

Approach to universal self-similar attractor for the levelling of thin liquid films

et al. 2014

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We compare the capillary levelling of a random surface perturbation on a thin polystyrene film with a theoretical study on the two-dimensional capillary-driven thin film equation. Using atomic force microscopy, we follow the time evolution of samples prepared with different initial perturbations of the free surface. In particular, we show that the surface profiles present long term self-similarity, and furthermore, that they converge to a universal self-similar attractor that only depends on the volume of the perturbation, consistent with the theory. Finally, we look at the convergence time for the different samples and find very good agreement with the analytical predictions.

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Section: Introductionmentioning

confidence: 99%

Approach to universal self-similar attractor for the levelling of thin liquid films

et al. 2014

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“…One simple route to change the chain conformation is through the selection of the casting solvent. The solvent selection has been demonstrated to impact the aging properties and also the viscoelasticity of the thin films . However, the changes in the chain conformation have not been quantified, nor the role of residual solvent quantified.…”

Section: Discussionmentioning

confidence: 99%

“…The solvent selection has been demonstrated to impact the aging properties 205 and also the viscoelasticity of the thin films. 206,207 However, the changes in the chain conformation have not been quantified, nor the role of residual solvent quantified. Similarly, the relaxation behavior of nanoimprinted structures with entangled polymers is greatly enhanced due to residual stresses in the material, 59 where the chain conformation is also likely far from equilibrium.…”

Section: Entanglements and Chain Conformation In Confinementmentioning

confidence: 99%

Mechanical and viscoelastic properties of confined amorphous polymers

Vogt

2017

J Polym Sci B Polym Phys

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Confinement of polymers to nanoscale dimensions can dramatically impact their physical properties. Substantial efforts have focused on the glass transition temperature (T g ) of polymers confined to thin films, but their mechanical properties are less studied despite their technological importance. In this review, challenges with mechanical measurements of polymer thin films are discussed along with novel metrologies that provide insight into their mechanical properties. A comparison of experimental measurements, simulations and theory provide several general conclusions about the mechanical properties under confinement. Confinement impacts the elastic modulus, rubbery compliance and viscosity of polystyrene, the archetypal polymer for confinement, but the confinement effect appears to depend on the measurement technique. This effect may be due to the details of averaging of gradients in properties that are dependent on the measurement details. Routes to minimize confinement effects are addressed. Despite progress in the measurements of mechanical properties of polymer thin films, there remain unresolved questions about the impact of confinement, which we highlight at the end of this review. 1,2 These concerns persist for polymeric nanostructures, where mechanical properties are critical to feature stability. 3 The mechanical properties of many polymers are dependent on their processing history,

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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.…”

mentioning

confidence: 93%

“…In the poor solvents, globular molecules aggregate with one another and then precipitate after each of the aggregates increases in size beyond a critical level. 4 Macroscopically, phase separation proceeds. These globules are not generally stable and entanglements are immediately formed following precipitation.…”

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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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Equilibration of Polymer Films Cast from Solutions with Different Solvent Qualities

Cited by 40 publications

References 24 publications

Approach to universal self-similar attractor for the levelling of thin liquid films

Approach to universal self-similar attractor for the levelling of thin liquid films

Mechanical and viscoelastic properties of confined amorphous polymers

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

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