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Highly transparent thermoresponsive surfaces based on tea‐stain‐inspired chemistry
Author(s) -
Dong Fuxin,
Li Yue,
Yuan Xiaohua,
Wang Ping,
Yang Junjie,
Miao Lei
Publication year - 2018
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.46694
Subject(s) - tannic acid , alkyl , chemistry , polymer chemistry , aqueous solution , poly(n isopropylacrylamide) , polymerization , atom transfer radical polymerization , coating , chemical engineering , polymer , contact angle , wetting , materials science , organic chemistry , engineering , copolymer
A highly transparent thermoresponsive surface that could switch its wettability at different temperatures was constructed via tea‐stain‐inspired chemistry. The pristine tannic acid was modified by alkyl bromide with a substitution degree of 1.7 alkyl bromide units per tannic acid molecule. A coating of the alkyl bromine modified tannic acid with a thickness of 22 ± 3 nm was deposited onto the surface of glass via auto‐oxidation. A poly( N ‐isopropylacrylamide) (PNIPAAm) brush was grafted from the alkyl bromide initiator via surface initiation atom transfer radical polymerization with a polymer grafting density of 8.6 × 10 −3 mg/cm 2 . Due to the low thickness of the tannic acid and PNIPAAm coating, the transparency of this thermoresponsive surface remained constant at 94.3% even when the temperature was changed from 20 to 40 °C, but the water contact angle of this surface increased rapidly when the temperature was elevated from 25 to 35 °C. Due to the inevitable hydrolysis and deprotonation, this tea‐stain‐inspired chemistry‐based coating was stable in aqueous solution with a pH of 7 or isopropanol for soaking times of up to 24 h. The coating reported here may have various potential applications such as surfaces for cell culture media, food storage, or self‐cleaning materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46694.