2012/10/23 by Robert J. Vrancken, Vrancken, Robert J., Matthew L. Blow +13
Biochemistry, Genetics and Molecular Biology · Engineering · Materials Science · Physics and Astronomy · #Anisotropy #Composite material #Condensed matter physics #Contact angle #Diamond #Diffusion and Search Dynamics #Drop (telecommunication) #Drop impact #FOS: Physical sciences #Fluid Dynamics and Heat Transfer #Lattice (music) #Lattice Boltzmann Simulation Studies #Lattice Boltzmann methods #Materials science #Mechanical engineering #Mechanics #Microfluidics #Nanomaterials and Printing Technologies #Nanotechnology #Optics #Physics #Pickering emulsions and particle stabilization #Soft Condensed Matter (cond-mat.soft) #Wetting #cond-mat.soft
paper · pdf · doi:10.48550/arxiv.1210.6244
published in arXiv (Cornell University) (Cornell University) · 12 pages + 2 pages supporting information Accepted for publication in Soft Matter
arxiv created 2012/10/23 · openalex publication_date 2012/10/23 · arxiv updated 2012/10/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present results showing how water drops, produced by ink-jet printing,\nspread on surfaces patterned with lattices of diamond or triangular posts.\nConsidering post widths typically ~7 m and lattice spacings between 15-40 m, we\nobserve drop shapes with 3,4 and 6-fold symmetry, depending on both the\nsymmetry of the lattice and the shape of the posts. This is a result of the\ndifferent mechanisms of interface pinning and depinning which depend on the\ndirection of the contact line motion with respect to the post shape. Lattice\nBoltzmann simulations are used to describe these mechanisms in detail for\ntriangular posts. We also follow the motion of the contact line as the drops\nevaporate showing that they tend to return to their original shape. To explain\nthis we show that the easy direction for movement is the same for spreading and\ndrying drops. We compare the behaviour of small drops with that of larger drops\ncreated by jetting several drops at the same position. We find that the contact\nline motion is unexpectedly insensitive to drop volume, even when a spherical\ncap of fluid forms above the posts. The findings are relevant to microfluidic\napplications and to the control of drop shapes in ink-jet printing.\n