Quasi-logarithmic spacing law in dewetting patterns from the drying meniscus of a polymer solution

Abstract

ABSTRACT:We report on a periodic precipitation pattern emerged from a drying meniscus via evaporation of a polystyrene solution in a Petri dish. It appeared a quasi-logarithmic spacing relation in the pattern as a result of stick-slip motion of the contact line towards the wall. A model based on the dynamics of the evaporating meniscus is proposed.

A model for pattern deposition from an evaporating solution subject to contact angle hysteresis and finite solubility

“…We use our model to study the pattern deposition for pinned and un-pinned contact lines and for an interchanging stick-slip motion of the contact line. We characterise the patterns by performing a parametric study, confirming previous experimental results 7,16,18,19,33,35 and giving further insights. In the following we derive our model in Section 2, discuss the method of solution in Section 3, summarize our findings in Section 4, and conclude in Section 5.…”

“…Accordingly, we denote by y n and y n+1 the contact angles at the pinned positions R n and R n+1 , respectively. In a similar manner to Chen et al, 33 we employ the assumption that y n+1 is equal to the receding contact angle on a bare substrate, that is y n+1 = 1. Using the last constraint which was prescribed in problem (1) for the two corresponding drops' shapes (before and after the de-pinning), where the corresponding volume loss in each case is calculated according to (4), we get the following cubic equation for R n+1 :…”

“…Furthermore, studying the stick-slip motion of the meniscus in the case of a Petri dish geometry, Chen et al 33 proposed a piece-wise model that takes into account the antagonistic balance between the pinning and de-pinning mechanisms, assuming a constant evaporation rate. Chen and coworkers related pinning/de-pinning mechanisms, the receding contact angle, and the roughness of the substrate, where they based their analysis on the relationship between the receding contact angle and the roughness of the solid substrate obtained by de Gennes.…”

“…In this paper, we present a piece-wise model, reminiscent of the models by Kaya et al 32 and Chen et al, 33 for the pattern deposition of the solute mass from an evaporating drop whose contact line undergoes a stick-slip motion as a function of the receding contact angle threshold on the bare substrate and on the deposit. We assume a diffusion limited evaporation 7,8,18,19 and further incorporate the standard Fick's diffusion law 27 in the advection-diffusion equation for the diffusive flux in the solution.…”

Self-organized Archimedean spiral pattern: Regular bundling of fullerene through solvent evaporation

“…Precipitation via the evaporation of solutions containing the aforementioned building blocks near the contact line at a meniscus produces regular periodic-stripe patterns. Dispersed solutes have been shown to be transferred to the vicinity of the contact line by capillary flow and then self-assembled into stripe patterns by a stick-slip cycle [6]. In addition, a gradient stripe pattern has been found in the evaporation process of a confined solution [3,6].…”