Formation of nanopillar arrays in ultrathin viscous films: the critical role of thermocapillary stresses.

@article{Dietzel2009FormationON,
  title={Formation of nanopillar arrays in ultrathin viscous films: the critical role of thermocapillary stresses.},
  author={Mathias Dietzel and Sandra M. Troian},
  journal={Physical review letters},
  year={2009},
  volume={103 7},
  pages={
          074501
        }
}
Experiments by several groups during the past decade have shown that a molten polymer nanofilm subject to a large transverse thermal gradient undergoes spontaneous formation of periodic nanopillar arrays. The prevailing explanation is that coherent reflections of acoustic phonons within the film cause a periodic modulation of the radiation pressure which enhances pillar growth. By exploring a deformational instability of particular relevance to nanofilms, we demonstrate that thermocapillary… 

Figures from this paper

Experimental verification of the formation mechanism for pillar arrays in nanofilms subject to large thermal gradients.

TLDR
Early time measurements of the array pitch and growth rate in polymer melts confirm a formation process based on a long wavelength thermocapillary instability and not electrostatic attraction or acoustic phonon driven growth as previously believed.

Mechanism for spontaneous growth of nanopillar arrays in ultrathin films subject to a thermal gradient

Several experimental groups have reported spontaneous formation of periodic pillar arrays in molten polymer nanofilms confined within closely spaced substrates held at different temperatures. These

Influence of gas rarefaction on the lateral resolution achievable by thermocapillary patterning

Molten polymer nanofilms subject to a large transverse thermal gradient can undergo a thermocapillary instability leading to the growth of nanopillar arrays on the cooler side. The array pitch can be

Early time instability in nanofilms exposed to a large transverse thermal gradient: Improved image and thermal analysis

Liquid nanofilms exposed to a large transverse thermal gradient undergo an instability featuring an array of nanopillars whose typical pitch is tens of microns. In earlier works, a comparison of this

Enhanced Electrically Induced Micropatterning of Confined Thin Liquid Films: Thermocapillary Role and Its Limitations

Electrohydrodynamic (EHD) and thermocapillary (TC) forces are used to destabilize the interface of ultra-thin liquid films and create submicron sized features. EHD instabilities result from normal

Thermo-Electrohydrodynamic Patterning in Nanofilms.

TLDR
To improve the electrically assisted patterning process and create smaller sized features with the higher active surface area, the combined thermocapillary-electrohydrodynamic (TC-EHD) instability of liquid nanofilms is considered and increase in the thermal conductivity ratio of layers changes the mechanism of pattern formation.

Differential colorimetry measurements of fluctuation growth in nanofilms exposed to large surface thermal gradients

Slender liquid nanofilms exposed to large surface thermal gradients are known to undergo thickness fluctuations, which rapidly self-organize into arrays of nanoprotrusions with a separation distance

Combined thermal and electrohydrodynamic patterning of thin liquid films

Both electric fields and temperature gradients can destabilize the surface of a thin liquid film and lead to the self-assembly of patterns composed of pillar-like structures. Such instabilities offer

Mathematical modelling of thermocapillary patterning in thin liquid film: an equilibrium study

Abstract Thermocapillary patterning, namely, the formation of micro/nano patterns in a liquid film by surface deformation induced by an imposed thermal gradient, has enjoyed widespread applications

References

SHOWING 1-10 OF 36 REFERENCES

Morphological Instability of a Confined Polymer Film in a Thermal Gradient

We report the experimental observation of a morphological instability of a confined polymer-air double layer sandwiched between two plates set to different temperatures. The homogeneous temperature

Temperature-gradient–induced instability in polymer films

We report the experimental observation and a theoretical model for a thin-film instability caused by a temperature gradient. A polymer-air double layer sandwiched between two plates set to different

Molecular forces caused by the confinement of thermal noise.

TLDR
It is proposed that the geometrical confinement of thermally excited acoustic waves gives rise to a force that is strong enough to destabilize thin films, which is of similar magnitude as van der Waals forces.

Viscosity of entangled polystyrene thin film melts: Film thickness dependence.

  • J. MassonP. Green
  • Materials Science
    Physical review. E, Statistical, nonlinear, and soft matter physics
  • 2002
TLDR
It is shown that the viscosity decreases appreciably with decreasing thickness for 25<h<50 nm, which is consistent with studies which suggest that the glass transition of entangled polystyrene thin film melts on SiO(x)/Si substrates exhibit an apparent decrease with decreasing film thickness over the same range of h.

3D Large scale Marangoni convection in liquid films

Abstract.We study large scale surface deformations of a liquid film unstable due to the Marangoni effect caused by external heating on a smooth and solid substrate. The work is based on the thin film

Dewetting of Ni and NiAg solid thin films and formation of nanowires on ripple patterned substrates

The solid state dewetting process of thin Ni films during thermal annealing on smooth and ripple patterned silicon dioxide was investigated. The ripple pattern was created by ion etching under

Formation of patterns induced by thermocapillarity and gravity

Consider a liquid film on a slightly inclined plane driven by gravity and thermocapillarity. We derive an equation describing the nonlinear evolution of the interface between the liquid and the

Lithographically induced self-assembly of periodic polymer micropillar arrays

We observed, and believe it to be the first time, the self-formation of periodic, supramolecular (micrometer scale) pillar arrays in a thin, single-homopolymer film melt, which was originally flat on

Phonon attenuation in amorphous solids studied by picosecond ultrasonics.

  • MorathMaris
  • Materials Science
    Physical review. B, Condensed matter
  • 1996
TLDR
A picosecond optical technique is used to measure the attenuation of longitudinal-acoustic phonons in several disordered solids and finds a universal behavior for frequencies up to 320 GHz and for temperatures between 80 and 300 K.