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Controllable Hierarchical Surface Patterns of Supramolecular Hydrogels: Harnessing Buckling Instability by Confinement
Author(s) -
Li Xiaohui,
Guo Mingyu,
Wang Fang,
Shen Xuezhen,
Weng Yuyan,
Hu Zhijun
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201703155
Subject(s) - materials science , self healing hydrogels , supramolecular chemistry , nanotechnology , perpendicular , instability , polymer , buckling , polyethylene glycol , surface (topology) , composite material , chemical engineering , polymer chemistry , crystallography , geometry , chemistry , crystal structure , mathematics , physics , mechanics , engineering
Abstract Patterned surfaces of responsive polymers find applications in diverse fields. However, it is still a great challenge to fabricate hierarchical patterns with long‐range orders. Herein controllable hierarchical surface patterns that can be fabricated by combining nanoembossing techniques with the surface instability of supramolecular hydrogels are presented. Nanoembossed nanostripe arrays of polyethylene glycol (PEG)‐based polyurethane–urea supramolecular hydrogels are fabricated and exposed to water, whereby the lateral expansion of nanostripes is confined and leads to the formation of folded in‐plane or out‐of‐plane patterns depending on the aspect ratios. The direction of folds is perpendicular to the nanostripes. Both the amplitude and the wavelength of out‐of‐plane folds are proportional to the thickness of nanostripes. Therefore, hierarchical structures, in which one periodicity is defined by the nanoembossing processes and the other is determined by surface buckling, can be quickly fabricated in supramolecular hydrogel thin films.