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Two‐Dimensional Marangoni‐Instability‐Induced Periodic Patterns of Polymer Blend Films Cast on Tilted Substrates
Author(s) -
Wu KuenHua,
Lu ShihYuan,
Chen HsinLung,
Chen YenYi
Publication year - 2008
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200700471
Subject(s) - marangoni effect , materials science , surface tension , instability , polymer , polymer blend , viscosity , polymer chemistry , marangoni number , composite material , thermodynamics , copolymer , physics , mechanics
Two‐dimensional periodic patterns were observed for PS/PVP blend films and the corresponding homopolymer films on tilted glass substrates. They were attributed to the Marangoni instability resulting from surface tension non‐uniformity. For the 1:1 PS‐1/PVP‐1 blend films, two‐dimensional regular arrays of the separated phases were observed, similar to those observed on homopolymer films from thickness variations. In addition, for the PS‐2/PVP‐2 blend films of 30/70 composition, one‐dimensional strip patterns of separated phases were observed. The pattern formation mechanism is discussed and a characteristic parameter, defined as the ratio of the final film thickness to initial solution viscosity, is found to correlate well with the pattern regularity through variation in polymer concentration.