Surface properties of poly(oxyethylene)s with alkyl thioether side chains (CH3-nTE; n = carbon atoms in the side chain) were investigated. CH3-nTEs having shorter side chains (n = 6, 8, 10) did not have ordered structures, while those with longer chains (n = 12, 14) showed well-ordered, lamellar structures with side chain crystalline domains. Accordingly, CH3-12TE and CH3-14TE film surfaces were much more enriched with hydrophobic alkyl side chains than CH3-8TE and CH3-10TE surfaces. However, CH3-12TE and CH3-14TE films had smaller water contact angles (approximate to 114 degrees) than CH3-8TE and CH3-10TE films (>130 degrees). This unexpected behavior is ascribed to the formation of very rough CH3-8TE and CH3-10TE film surfaces (R-rms > 100 nm) on contact with water. The CH3-10TE/poly(methyl methacrylate) (PMMA) surfaces also showed high water contact angles (>125 degrees), even with low CH3-10TE content (30 wt%), because the CH3-10TE moiety roughened the surfaces. Furthermore, ultra-hydrophobic sticky behavior was observed for CH3-nTEs (n = 8, 10) and CH3-10TE/PMMA surfaces. (C) 2016 Elsevier Inc. All rights reserved.