# Difference between revisions of "Liquids on topologically nano-patterned surfaces"

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With their patterned silicon/MCH system, the authors set out to validate theories on the dependence of liquid thin film thickness, <math>d</math>, on chemical potential difference, <math>\Delta \mu</math>. From previous work in the Pershan lab and others, the thickness of a film on a flat surface with van der Waals absorption, the authors expect a power-law of <math>d \propto \Delta \mu^{-1/3}</math>. However, for a surface containing isolated, infinitely deep parabolic cavities, the power law is expected to be roughly <math>d \propto \Delta \mu^{-3.4}</math>. | With their patterned silicon/MCH system, the authors set out to validate theories on the dependence of liquid thin film thickness, <math>d</math>, on chemical potential difference, <math>\Delta \mu</math>. From previous work in the Pershan lab and others, the thickness of a film on a flat surface with van der Waals absorption, the authors expect a power-law of <math>d \propto \Delta \mu^{-1/3}</math>. However, for a surface containing isolated, infinitely deep parabolic cavities, the power law is expected to be roughly <math>d \propto \Delta \mu^{-3.4}</math>. | ||

− | From XR data taken on their samples, the authors calculate the electron density in the well and on the flat surface (see figure 1). | + | From XR data taken on their samples, the authors calculate the electron density, <math>\rho</math>, in the well and on the flat surface (see figure 1). They then introduce the areal adsorption, <math>\Gamma</math>, which is defined as: <math>\Gamma = \langle\int_0^{\infty}\rangle></math> |

## Revision as of 12:56, 24 February 2009

"Liquids on Topologically Nanopatterned Surfaces"

Oleg Gang, Kyle J. Alvine, Masafumi Fukuto, Peter S. Pershan, Charles T. Black, and Benjamin M. Ocko

Physical Review Letters 95(21) 217801 (2005)

## Soft Matter Keywords

liquid thin film, wetting, laterally heterogeneous surface

## Summary

Gang, et al. present experimental work performed to verify theory on the wetting of thin films. Working with a nanopatterned silicon surface and a film of methyl-cyclohexane (MCH), the authors should that film thickness has two different power law dependences on chemical potential offset from the bulk liquid-vapor equilibrium. These two dependences delineate two regimes of film growth. The first regime is characterized by constant film thickness on the surface and filling of the nanowells, while the second regime is characterized by growth of the surface film after the wells have been completely filled. The behavior of the film is studied using x-ray reflectivity (XR) and grazing incidence diffraction (GID).

## Practical Application of Research

Though not all results from this paper fully explained by theory, the authors have shown that film thickness on a heterogeneous surface is controllable. Deposition of coatings will benefit from this work, and it is feasible that nanopatterning a surface before deposition can help give an extra bit of control over the liquid thin film.

## Thin Film Thickness

With their patterned silicon/MCH system, the authors set out to validate theories on the dependence of liquid thin film thickness, <math>d</math>, on chemical potential difference, <math>\Delta \mu</math>. From previous work in the Pershan lab and others, the thickness of a film on a flat surface with van der Waals absorption, the authors expect a power-law of <math>d \propto \Delta \mu^{-1/3}</math>. However, for a surface containing isolated, infinitely deep parabolic cavities, the power law is expected to be roughly <math>d \propto \Delta \mu^{-3.4}</math>.

From XR data taken on their samples, the authors calculate the electron density, <math>\rho</math>, in the well and on the flat surface (see figure 1). They then introduce the areal adsorption, <math>\Gamma</math>, which is defined as: <math>\Gamma = \langle\int_0^{\infty}\rangle></math>