Stripe coating with a coffee‐ring effect for color filter solutions

Lin, Yu‐Chih; Lin, Yu-Yan; Wong, David Shan Hill; Liu, Ta‐Jo; Wen, Shu-Heng; Huang, Kuo-Tung

doi:10.1002/app.33124

Cited by 6 publications

(2 citation statements)

References 17 publications

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“…Coffee ring phenomenon is commonly observed during evaporating droplet containing nonvolatile solutes resulted from a combination of capillary flow and pinning of the contact line (CL) and has attracted great research interest because of its broad practical applications in inkjet printing, − functional coating, spot test analysis, , color filter, chromatography, , etc. The physical mechanisms behind it are rather complex and have been extensively studied experimentally and theoretically. − The method for suppressing coffee ring effect presents one of the most fundamental issues and plays an utmost important role in high-resolution inkjet printing technique because of the usual non-uniformity of deposited structures.…”

Section: Introductionmentioning

confidence: 99%

Suppression of the Coffee Ring Effect by Hydrosoluble Polymer Additives

Cui

Zhang

et al. 2012

ACS Appl. Mater. Interfaces

179

162

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A simple and novel method has been demonstrated for avoiding coffee ring structure based on hydrosoluble polymer additives during droplet evaporation. The polymer additives lead to the motion of the contact line (CL) resulted from the viscosity and Marangoni effect. The viscosity provides a large resistance to the radially outward flow. It results in a small amount of spheres deposited at droplet edge, which do not facilitate the pinning of the CL. The Marangoni effect resulted from the variation of polymer concentration at droplet edge during droplet evaporation contributes to the motion of the CL. Thus, uniform and ordered macroscale SiO(2) microspheres deposition is achieved. What's more, the coffee ring effect can be eliminated by different hydrosoluble polymer. This method will be applicable to a wide of aqueous system and will be of great significance for extensive applications of droplet deposition in biochemical assays and material deposition.

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Section: Introductionmentioning

confidence: 99%

Suppression of the Coffee Ring Effect by Hydrosoluble Polymer Additives

Cui

Zhang

et al. 2012

ACS Appl. Mater. Interfaces

179

162

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“…A new and better approach is to coat narrow RGB stripes directly on a large piece of glass, whereby most of the RGB solution is preserved . A recent survey on drying of stripe color filter materials reveals that coffee rings could form under certain drying conditions . Hence, a thorough understanding of the coating mechanism of narrow stripes is required before this new approach can be accepted as a reliable production means.…”

Section: Introductionmentioning

confidence: 99%

Operating windows of stripe coating

Lin

Wang

et al. 2013

Asia-Pacific J Chem Eng

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The fluid mechanics of narrow stripe coating for low viscosity Newtonian solutions was investigated. A narrow stripe could be produced either through a slot die with a shim to control the slot width or through a rectangular nozzle. A flow visualization technique was employed to observe the mechanism on how a narrow stripe breaks at high coating speeds. Two-dimensional and three-dimensional numerical simulations on coating flows were also carried out to examine the fluid motion. The coating solution was found to expand laterally after emanating from the slot die channel at low coating speeds. The stripe width contracts gradually with increasing coating speed until coating failures appear. The coating defect observed switches from ribbing to a periodic stable and break-up motion. The effects of various fluid properties, geometric and operating parameters on the variation of coating width and maximum coating speeds were examined. A universal correlation involving two dimensionless groups, Reynolds and Bond number, was established for the prediction of coating width.

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An Efficiently Doped PEDOT:PSS Ink Formulation via Metastable Liquid−Liquid Contact for Capillary Flow‐Driven, Hierarchically and Highly Conductive Films

Qiu

et al. 2023

Small

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With commercial electronics transitioning toward flexible devices, there is a growing demand for high‐performance polymers such as poly(3,4‐ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS). Previous breakthroughs in promoting the conductivity of PEDOT:PSS, which mainly stem from solvent‐treatment and transfer‐printing strategies, remain as inevitable challenges due to the inefficient, unstable, and biologically incompatible process. Herein, a scalable fabrication of conducting PEDOT:PSS inks is reported via a metastable liquid−liquid contact (MLLC) method, realizing phase separation and removal of excess PSS simultaneously. MLLC‐doped inks are further used to prepare ring‐like films through a compromise between the coffee‐ring effect and the Marangoni vortex during evaporation of droplets. The specific control over deposition conditions allows for tunable ring‐like morphologies and preferentially interconnected networks of PEDOT:PSS nanofibrils, resulting in a high electrical conductivity of 6,616 S cm−1 and excellent optical transparency of the film. The combination of excellent electrical properties and the special morphology enables it to serve as electrodes for touch sensors with gradient pressure sensitivity. These findings not only provide new insight into developing a simple and efficient doping method for commercial PEDOT:PSS ink, but also offer a promising self‐assembled deposition pattern of organic semiconductor films, expanding the applications in flexible electronics, bioelectronics as well as photovoltaic devices.

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Stripe coating with a coffee‐ring effect for color filter solutions

Cited by 6 publications

References 17 publications

Suppression of the Coffee Ring Effect by Hydrosoluble Polymer Additives

Suppression of the Coffee Ring Effect by Hydrosoluble Polymer Additives

Operating windows of stripe coating

An Efficiently Doped PEDOT:PSS Ink Formulation via Metastable Liquid−Liquid Contact for Capillary Flow‐Driven, Hierarchically and Highly Conductive Films

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