Lines of dense nanoparticle colloidal suspensions evaporating on a flat surface: Formation of non-uniform dried deposits

A. L. Yarin, J. B. Szczech, C. M. Megaridis, J. Zhang, D. R. Gamota

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Line evaporation of dense nanoparticle suspensions is studied theoretically and experimentally. The 2-D lines are drawn by a pen-like nozzle continuously dispensing a commercially available concentrated organic suspension (50 wt%; 4.3 vol%) of 5 nm gold nanoparticles in toluene solvent. Such particle-containing lines show promise for industrial applications where circuits are inkjet-printed and heat-treated to dry off the organic solvent and sinter the nanoparticles, thus producing a continuous electrically conducting path. The employed nanosuspension displays spontaneous thickening upon contact with a solid surface in the ambient atmosphere, and thus does not dry according to the well-established coffee-stain forming mechanism applicable to dilute particle suspensions. In the present work, model lines (∼1 mm width) are studied to elucidate the drying peculiarities of such nanoparticle slurries. These scaled-up lines allow detailed spatial measurements of their topography throughout their prolonged evaporation period, and make possible direct comparisons between experiment and theory. The results show the particle deposits formed by evaporative drying of these lines to be of non-uniform thickness with a dent in the middle of the lateral cross-section. Formation of this practically undesirable landscape is attributed to the highly non-uniform evaporative character of sessile or pendent liquid lines, which results in a non-uniform consolidation of the porous phase formed upon contact with the solid surface. The formulated description of the shape changing process, as done in the framework of the consolidation theory, yields predicted deposit speck shapes that compare favorably with the temporally resolved experimental data.

Original languageEnglish
Pages (from-to)343-354
Number of pages12
JournalJournal of Colloid and Interface Science
Volume294
Issue number2
DOIs
Publication statusPublished - 2006 Feb 15

Keywords

  • Drying
  • Evaporating slurry line
  • Film deposit
  • Nanoparticle colloidal suspension

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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