Header menu link for other important links
X
Tailoring crack morphology in coffee-ring deposits: Via substrate heating
Published in Royal Society of Chemistry
2017
PMID: 28714511
Volume: 13
   
Issue: 32
Pages: 5445 - 5452
Abstract
The drying of a sessile drop consisting of colloidal particles and the formation of particulate deposits with spatially periodic cracks were ubiquitous. The drying induced stress, which is generated during the evaporation of a colloidal drop, is released by the formation of cracks. We find that the morphology of cracks formed in particulate films dried at substrate temperature, Tsub = 25 °C is markedly different from that of cracks formed at Tsub > 45 °C. The cracks are disordered in the former case, but ordered and periodic in the latter. The disorderedness of cracks observed at Tsub = 25 °C is mainly due to the formation of a coffee-ring like particle deposit that exhibits a larger height gradient. The ultimate deposit pattern after complete drying is observed to be different for colloidal dispersion drops evaporated at different substrate temperatures. This is attributed to temperature-dependent solvent flow mechanisms and capillary-driven flow, which occur inside the colloidal drop during the course of drying. In addition, for the coffee-ring-like particulate deposit obtained at Tsub ≤ 45 °C, the ratio between the width of the deposit w and the radius of the ring R scales with the volume fraction of the colloids φ, w/R ∼ φ0.5, in the range of volume fractions studied in this work. The deposited patterns obtained at temperature Tsub > 45 °C are largely dominated by the capture of particles by the receding liquid-vapor interface. This is due to the faster rate of decrease of the liquid-vapor interface position with an increase in substrate temperature. © 2017 The Royal Society of Chemistry.
About the journal
JournalData powered by TypesetSoft Matter
PublisherData powered by TypesetRoyal Society of Chemistry
ISSN1744683X
Open AccessNo
Concepts (15)
  •  related image
    Colloids
  •  related image
    Cracks
  •  related image
    Deposits
  •  related image
    Drops
  •  related image
    Drying
  •  related image
    Volume fraction
  •  related image
    CAPILLARY-DRIVEN FLOWS
  •  related image
    Colloidal dispersion
  •  related image
    Colloidal particle
  •  related image
    Different substrates
  •  related image
    LIQUID-VAPOR INTERFACE
  •  related image
    PARTICLE DEPOSITS
  •  related image
    Substrate temperature
  •  related image
    Temperature dependent
  •  related image
    Interfaces (materials)