Pattern formation induced by an electric field in a polymer–air–polymer thin film system

Amarandei, George; Beltrame, Philippe; Clancy, Ian; O’Dwyer, Colm; Arshak, A.; Steiner, Ullrich; Corcoran, David; Thiele, Uwe

doi:10.1039/c2sm25273b

Cited by 37 publications

(75 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…-We here rigorously show that the regular part of eq. (16) as given by eqs (19), (20) and (21) converges in time to the Green's function of the purely viscous linear thin film equation (LTFE), as defined in [34]. For all Θ > 0 and all Q one has:…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…Enhanced mobility effects in ultra-thin polymer films have been predicted [10,11], and observed [12][13][14]. Film preparation by spincoating has also been widely studied [15][16][17][18], and is known to govern surface instabilities and pattern formation [19][20][21].The evolution of the free surface of a thin Newtonian liquid film with nonconstant curvature is driven by the Laplace pressure and mediated by viscosity. This is well understood from the theoretical point of view through the so-called capillary-driven thin film equation [1][2][3]22].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Viscoelastic effects and anomalous transient levelling exponents in thin films

Benzaquen¹,

Salez²,

Raphaël³

2014

EPL

View full text Add to dashboard Cite

-We study theoretically the profile evolution of a thin viscoelastic film supported onto a no-slip flat substrate. Due to the nonconstant initial curvature at the free surface, there is a flow driven by Laplace pressure and mediated by viscoelasticity. In the framework of lubrication theory, we derive a thin film equation that contains local viscoelastic stress through the Maxwell model. Then, considering a sufficiently regular small perturbation of the free surface, we linearise the equation and derive its general solution. We analyse and discuss in details the behaviour of this function. We then use it to study the viscoelastic evolution of a Gaussian initial perturbation through its transient levelling exponent. For initial widths of the profile that are smaller than a characteristic length scale involving both the film thickness and the elastocapillary length, this exponent is shown to reach anomalously high values at the elastic-to-viscous transition. This prediction should in particular be observed at sufficiently short times in experiments on thin polymer films.Over the past decades, the study of soft materials in confined geometries and thin films [1][2][3] has widely attracted the interest of physicists, biophysicists, chemists and engineers. In particular, thin polymer films are nowadays of major importance in several industrial applications such as biocompatible coatings, organic microelectronics and polymeric data storage devices. In order to gain insights into the behaviour of these films and their constitutive macromolecules, a wide class of experiments, including dewetting [4,5], nanoindentation with gold particles [6], and levelling of stepped films [7][8][9], have been performed. Enhanced mobility effects in ultra-thin polymer films have been predicted [10,11], and observed [12][13][14]. Film preparation by spincoating has also been widely studied [15][16][17][18], and is known to govern surface instabilities and pattern formation [19][20][21].The evolution of the free surface of a thin Newtonian liquid film with nonconstant curvature is driven by the Laplace pressure and mediated by viscosity. This is well understood from the theoretical point of view through the so-called capillary-driven thin film equation [1][2][3]22]. Extensive analytical work on the thin film equation [23][24][25][26][27] and numerous accurate numerical schemes [28][29][30][31] have been performed in the past decades, and have allowed for a deeper understanding of its mathematical features. Long-term traveling-wave solutions have been discussed [32]. Convergence of the solutions to intermediate asymptotic regimes [33] has also been revealed. In particular, it was shown that the vertically-rescaled solution for any summable initial profile uniformly converges in time towards a universal self-similar attractor that is precisely given by the Green's function of the capillary-driven linear thin film equation multiplied by the initial algebraic volume of the perturbation [34].The aforementioned capillary-driven thin fi...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Viscoelastic effects and anomalous transient levelling exponents in thin films

Benzaquen¹,

Salez²,

Raphaël³

2014

EPL

View full text Add to dashboard Cite

show abstract

“…The formation of patterns by highly dense assays of active filaments driven by hydrodynamic forces was reported in [240]. The application of a strong electric field resulted in the formation of patterns at polymer-air-polymer thin film interfaces [241]. The formation of desiccation cracks in clay-polymer films attached to a substrate was studied in [242].…”

Section: Pattern Formationmentioning

confidence: 99%

Novel experimentally observed phenomena in soft matter

Bandyopadhyay

2013

Pramana - J Phys

View full text Add to dashboard Cite

Abstract. Soft materials such as colloidal suspensions, polymer solutions and liquid crystals are constituted by mesoscopic entities held together by weak forces. Their mechanical moduli are several orders of magnitude lower than those of atomic solids. The application of small to moderate stresses to these materials results in the disruption of their microstructures. The resulting flow is non-Newtonian and is characterised by features such as shear rate-dependent viscosities and nonzero normal stresses. This article begins with an introduction to some unusual flow properties displayed by soft matter. Experiments that report a spectrum of novel phenomena exhibited by these materials, such as turbulent drag reduction, elastic turbulence, the formation of shear bands and the existence of rheological chaos, flow-induced birefringence and the unusual rheology of soft glassy materials, are reviewed. The focus then shifts to observations of the liquid-like response of granular media that have been subjected to external forces. The article concludes with examples of the patterns that emerge when certain soft materials are vibrated, or when they are displaced with Newtonian fluids of lower viscosities.

show abstract

“…Polymer films are likely prepared by spin-coating or dip-coating and classified as ultrathin films with a thickness < 100 nm or thin films with a thickness of 100 to 10,000 nm [1]. Due to the (visco-)elasticity of polymer films, the morphology can be influenced by interactions with the substrate or by external effects such as, e.g., temperature [2], humidity [3], pressure [4], electricity [5], light [6] or direct convection [7]. The adaptable morphology and response to external stimuli provides an excellent way for in situ handling of the morphology and properties of the polymer film.…”

Section: Introductionmentioning

confidence: 99%

Morphologies and Thermal Variability of Patterned Polymer Films with Poly(styrene-co-maleic anhydride)

Samyn

Schoukens

2014

Polymers

View full text Add to dashboard Cite

Patterned films of poly(styrene-co-maleic anhydride) copolymers were deposited by dip-coating from acetone solutions. A qualitative study of the film morphologies shows the formation of polymer spheres with smaller diameters at higher amounts of maleic anhydride (MA), and long-fibrous features at higher molecular weights. Upon heating, the films progressively re-assemble with short-and long-fibrous structures as a function of heating time and temperature. In parallel, the film morphologies are quantified by image processing and filtering techniques. The differential scanning calorimetry confirms the higher glass transition temperatures with increasing amount of MA. The analysis with Raman spectroscopy shows interactions between the molecules in solution and effects of ring-opening (hydrolysis) and ring-closure (formation of MA) during drying of the films. The water contact angles on the patterned films are within the hydrophilic range. They mainly correlate with the amount of MA moieties calculated from spectroscopy, while the roughness parameters have a minor effect. The variations in film patterns illustrate the self-assemble ability of the copolymers and confirm a heterogeneous molecular structure, as previously assumed.

show abstract

Pattern formation induced by an electric field in a polymer–air–polymer thin film system

Cited by 37 publications

References 49 publications

Viscoelastic effects and anomalous transient levelling exponents in thin films

Viscoelastic effects and anomalous transient levelling exponents in thin films

Novel experimentally observed phenomena in soft matter

Morphologies and Thermal Variability of Patterned Polymer Films with Poly(styrene-co-maleic anhydride)

Contact Info

Product

Resources

About