Control of the structuring of thin soft matter films by means of different types of external disturbance

Regular Surface Patterns on Rayleigh-Taylor Unstable Evaporating Films Heated from Below

“…Surface patterns of thin liquid films on a solid support were studied during the last decade in numerous experimental and theoretical contributions (see [1][2][3][4][5][6][7][8] and references therein). In coating or wetting processes, a plane surface is usually desirable and the formation of surface deflections should be avoided.…”

“…One possibility is to use a structured substrate [1,2]. In the present Letter we wish to concentrate on another method: the self-organized pattern growth due to an instability mechanism of the initially flat film [3,4]. There are several mechanisms that may destabilize a flat surface and allow us to control the growth of surface patterns.…”

Dry-spot nucleation in thin liquid films on chemically patterned surfaces

“…Sehgal et al (2002) and Zhang et al (2003) performed experiments regarding the dewetting of polystyrene layers on periodically heterogeneous substrates. Thiele et al considered the morphology evolution in a thin liquid film on substrates with one-and two-dimensional sinusoidal surface energy modulation (Brusch et al 2002;Thiele et al 2003;Pototsky et al 2004). Kao et al (2006) investigated the rupture of thin liquid films on substrates with sinusoidal and square-wave resonant surface energy patterning.…”

“…This allows parametrization of arbitrary experimental disjoining pressure isotherms, at least over a finite range of film thicknesses. While several groups have already studied dewetting of thin liquid films on structured surfaces (Kargupta et al 2000;Kargupta and Sharma 2002;Kargupta and Sharma 2003;Sehgal et al 2002;Zhang et al 2003;Brusch et al 2002;Thiele et al 2003;Pototsky et al 2004;Kao et al 2006;Julthongpiput et al 2007;Zhu et al 2010), most of the results have been obtained for small film thicknesses on order of ten times the precursor layer thickness, very specific disjoining pressure isotherms with more than one inflection point or neglecting the influence of gravity. For industrial applications relevant film thicknesses range typically between 1 and 10 lm, which is several orders of magnitude above the precursor layer thickness such that the influence of gravity can be substantial if not decisive.…”

Sequence, symmetry and pattern formation

“…Therefore we need nonlinear equations of generalized coordinates. Also we want general equations for locally different physical systems which show similar pattern formation for instance the rolls in convection [2], thin fluid layer [3], reaction-diffusion [2][3][4], surface (Faraday) waves [2,5], and granular systems [6], the spirals in convection [2] and granular system [6], etc. In other words we need a foundation for dynamics in nonlocal approach.…”