Central spot formed in dried coffee-water-mixture droplets: Inverse coffee-ring effect

2018 ◽  
Vol 18 (4) ◽  
pp. 477-483 ◽  
Author(s):  
Ji Min Baek ◽  
Changhyun Yi ◽  
Joo Yull Rhee
Keyword(s):  
Water Mixture ◽  
Central Spot ◽  
Coffee Ring ◽  
Coffee Ring Effect ◽  
Ring Effect

scholarly journals Understanding the Coffee ring Effect on Self‐discharge Behavior of Printed micro‐Supercapacitors

2021 ◽  
Author(s):  
Jingzhi Hu ◽  
Zhaohua Xu ◽  
Kai Yuan ◽  
Chao Shen ◽  
Keyu Xie ◽  
...  
Keyword(s):  
Coffee Ring ◽  
Discharge Behavior ◽  
Coffee Ring Effect ◽  
Ring Effect

Influence of membrane character on suppression of coffee-ring effect

2021 ◽  
Author(s):  
S.S. Shahruddin ◽  
N. Ideris ◽  
N.F. Abu Bakar ◽  
A.L. Ahmad ◽  
N.F.C. Lah
Keyword(s):  
Coffee Ring ◽  
Coffee Ring Effect ◽  
Ring Effect

Stability improvement for dried droplet pretreatment by suppression of coffee ring effect using electrochemical anodized nanoporous tin dioxide substrate

2020 ◽  
Vol 187 (12) ◽  
Author(s):  
Yuanchao Liu ◽  
Jie Pan ◽  
Zhenlin Hu ◽  
Yanwu Chu ◽  
Muhammad Shehzad Khan ◽  
...  
Keyword(s):  
Tin Dioxide ◽  
Coffee Ring ◽  
Coffee Ring Effect ◽  
Ring Effect

Beyond the coffee-ring effect: Pattern formation by wetting and spreading of drops

2018 ◽  
Vol 98 (4) ◽  
Author(s):  
Dileep Mampallil ◽  
Meenakshi Sharma ◽  
Ashwini Sen ◽  
Shubham Sinha
Keyword(s):  
Pattern Formation ◽  
Coffee Ring ◽  
Coffee Ring Effect ◽  
Ring Effect

scholarly journals Position Dependence of Emission Wavelength of a SiO2 Colloidal Photonic-Crystal Laser

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 802 ◽  
Author(s):  
Ting-Hui Chen ◽  
Bing-Yau Huang ◽  
Chie-Tong Kuo
Keyword(s):  
Photonic Crystal ◽  
Colloidal Crystal ◽  
Threshold Energy ◽  
Silica Particles ◽  
Wavelength Tunable ◽  
Coffee Ring ◽  
Crystal Laser ◽  
Coffee Ring Effect ◽  
Photonic Crystal Laser ◽  
Ring Effect

In this paper, a wavelength tunable colloidal-crystal laser with monodispersed silica particles was demonstrated. Silica particles were synthesized through the modified Stöber process and self-assembled into the colloidal photonic-crystal structure, which was then used to form the optic cavity of a wavelength tunable laser device. Due to Bragg’s diffraction of the colloidal photonic-crystal and the coffee ring effect, the forbidden energy gap of light varied with different lattice sizes at different positions of the colloidal photonic-crystal. When the pumping pulsed laser irradiated on the gain medium of the sample, the fluorescence was restricted and enhanced by the colloidal photonic-crystal. Lasing emission with a single peak occurred when the energy of the pumping laser exceeded the threshold energy. The threshold energy and the full-width at half-maximum (FWHM) of the proposed laser were 7.63 µJ/pulse and 2.88 nm, respectively. Moreover, the lasing wavelength of the colloidal photonic-crystal laser could be tuned from 604 nm to 594 nm, corresponding to the various positions in the sample due to the coffee ring effect.

scholarly journals Evaporation-Induced Crystal Nucleation and Morphology of Dried Poly(Vinylidene Fluoride) Droplets

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1442
Author(s):  
Yongri Liang ◽  
Susu Wang
Keyword(s):  
Droplet Size ◽  
Evaporation Rate ◽  
Vinylidene Fluoride ◽  
Grazing Incidence ◽  
Solvent Evaporation ◽  
Crystal Nucleation ◽  
Coffee Ring ◽  
Poly Vinylidene Fluoride ◽  
Coffee Ring Effect ◽  
Ring Effect

The evaporation of a polymer solution droplet is important in solution-based polymer film fabrications, such as inkjet printing, spray coatings, and droplet casting, etc. In this work, we investigated the effect of droplet size, solvent evaporation rate, and concentration on the “coffee-ring” effect, crystal nucleation, polymorphism, and morphology of dried poly (vinylidene fluoride) (PVDF) solution droplets with the atomic force microscopy (AFM) and two-dimensional grazing incidence wide angle X-ray scattering (2D GIWAXS) method. We found that the crystal structure, morphology and crystal distribution in the center and edge regions of dried PVDF droplets were different due to the “coffee-ring” effect. The “coffee-ring” effect of dried PVDF droplets was mainly composited of accumulated crystals at the edge region of a droplet, which was mainly made by the crystallization of migrated chains. The interplay between the migration of chains and the crystallization and solidification of PVDF droplets significantly influenced the formation of the “coffee-ring”. In addition, our results showed that the decrease in droplet size and the controlling solvent evaporation rate were effective ways to improve the electroactive crystalline phases (β and γ-phases) nucleation and decrease the crystal size.

Sign in / Sign up

Export Citation Format

Share Document