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Creation of “Rose Petal” and “Lotus Leaf” Effects on Alumina by Surface Functionalization and Metal‐Ion Coordination
Author(s) -
Mukhopadhyay Rahul Dev,
Vedhanarayanan Balaraman,
Ajayaghosh Ayyappanpillai
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201709463
Subject(s) - contact angle , lotus effect , surface modification , petal , materials science , hysteresis , ligand (biochemistry) , lotus , alkoxy group , chemical engineering , nanotechnology , polymer chemistry , chemistry , alkyl , organic chemistry , composite material , botany , physics , receptor , biology , raw material , biochemistry , quantum mechanics , engineering
Functional differences between superhydrophobic surfaces, such as lotus leaf and rose petals, are due to the subtle architectural features created by nature. Mimicry of these surfaces with synthetic molecules continues to be fascinating as well as challenging. Herein, we demonstrate how inherently hydrophilic alumina surface can be modified to give two distinct superhydrophobic behaviors. Functionalization of alumina with an organic ligand resulted in a rose‐petal‐like surface (water pinning) with a contact angle of 145° and a high contact angle hysteresis (±69°). Subsequent interaction of the ligand with Zn 2+ resulted in a lotus‐leaf‐like surface with water rolling behavior owing to high contact angle (165°) and low‐contact‐angle‐hysteresis (±2°). In both cases, coating of an aromatic bis‐aldehyde with alkoxy chain substituents was necessary to emulate the nanowaxy cuticular feature of natural superhydrophobic materials.