Ultra-hydrophobic sticky polymer surfaces formed by water-induced surface deformation

Eun-Ho Sohn; Byoung Gak Kim; Hyunkee Hong; Da-Jung Sohn; Jong-Chan Lee

doi:10.1016/j.jcis.2016.11.019

Ultra-hydrophobic sticky polymer surfaces formed by water-induced surface deformation

J Colloid Interface Sci. 2017 Mar 15:490:84-90. doi: 10.1016/j.jcis.2016.11.019. Epub 2016 Nov 9.

Authors

Eun-Ho Sohn¹, Byoung Gak Kim¹, Hyunkee Hong², Da-Jung Sohn², Jong-Chan Lee³

Affiliations

¹ Interface Material and Chemical Engineering Research Center & Advanced Functional Polymer Research Center, Korea Research Institute of Chemical Technology, Daejon 305-343, Republic of Korea.
² Department of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shilim-9-Dong, Gwanak-Gu, Seoul 151-744, Republic of Korea.
³ Department of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shilim-9-Dong, Gwanak-Gu, Seoul 151-744, Republic of Korea. Electronic address: jongchan@snu.ac.kr.

PMID: 27870963
DOI: 10.1016/j.jcis.2016.11.019

Abstract

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 (≈114°) than CH₃-8TE and CH₃-10TE films (>130°). This unexpected behavior is ascribed to the formation of very rough CH₃-8TE and CH₃-10TE film surfaces (R_rms>100nm) on contact with water. The CH₃-10TE/poly(methyl methacrylate) (PMMA) surfaces also showed high water contact angles (>125°), even with low CH₃-10TE content (30wt%), 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.

Keywords: Poly(methyl methacrylte); Poly(oxyethylene)s with alkyl thioether side chains; Polymer blend; Ultra-hydrophobic sticky polymer surface; Water-induced surface deformation.